GNS Science Report 2013/45

BIBLIOGRAPHIC REFERENCE

Scott, B.J. 2013. A revised catalogue of Ruapehu volcano eruptive activity: 1830-2012, GNS Science Report 2013/45. 113 p.

B.J. Scott, GNS Science, Private Bag 2000, Taupo 3352

ISSN 1177-2425 ISBN 978-1-972192-92-4

CONTENTS ABSTRACT ...... IV KEYWORDS ...... IV 1.0 INTRODUCTION ...... 1 2.0 DATASETS ...... 2 3.0 CLASSIFICATION OF ACTIVITY ...... 3 4.0 DATA SET COMPLETNESS ...... 5 5.0 ERUPTION NARRATIVE ...... 6 6.0 LAHARS ...... 20 7.0 DISCUSSION...... 22 8.0 REFERENCES ...... 28

TABLES

Table 3.1 Magnitude scale for hazard zones established for historical eruptions at Ruapehu and return periods, after Houghton et al. (1987)...... 3 Table 3.2 Semi-quantitative estimate of the size of Ruapehu eruptions based on observed effects, after Sherburn et al. (1999)...... 3 Table 3.3 Semi-quantitative estimate of the size of Ruapehu eruptions based on observed effects, after Wilson (2009)...... 3 Table 3.4 Semi-quantitative estimate of the scale of Ruapehu eruptions based on observed effects (modified from Houghton et al., 1987; Sherburn et al., 1999 and Wilson, 2009)...... 4 Table 6.1 Summary of eruptive activity that has or may have produced lahars at Ruapehu...... 20 Table 7.1 List highlighting periods of enhanced eruptive activity that have been identified visually from the data set...... 23 Table 7.2 Frequency distribution for all eruptive activity observations post 1830 (181 years)...... 24 Table 7.3 Frequency distribution for all eruptive activity observations post 1940 (72 years)...... 24 Table 7.4 Eruption recurrence rates for the 1831 to 2012 data set (181 years)...... 26 Table 7.5 Eruption recurrence rates for the 1940 to 2012 data set (72 years)...... 26 Table 7.6 Frequency distribution for all eruptive activity observations post 1830, excluding the 1945 and 1995/1996 eruptive episodes and greater than scale 2...... 26 Table 7.7 Eruption recurrence rates for the 1830 to 2012 data set (177 years), excluding the 1945 and 1995/1996 eruptive episodes...... 27

FIGURES

Figure 4.1 Cumulative frequencey (red dots) and frequency (blue squares) plot of Ruapehu eruption scale data post 1830...... 5 Figure 5.1 The volcano of Ruapehu, Province of Auckland, NZ...... 7 Figure 5.2 View of Ruapehu Crater Lake on 5 April 1895 (Lands and Survey, 1895)...... 9 Figure 5.3 Image of Ruapehu in eruption 10 March 1895, reproduced in the supplement to the Auckland Weekly News 29 March 1906 (p.4)...... 9 Figure 5.4 View possibly from Waiouru showing eruption cloud over Mt Ruapehu, 28 April 1905...... 10 Figure 5.5 Otago Witness 8 May 1907: “The Crater Lake on Ruapehu recently in violent eruption”...... 10

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Figure 5.6 Aerial view of the crater, Mt Ruapehu, photographed by Whites Aviation in August 1947...... 12 Figure 5.7 Strongly steaming Crater Lake, 25 July 1966. Photo: J Healy, GNS VML 103437...... 13 Figure 5.8 Fresh low density lava fragment that was found in the outlet area, 3 August 1966...... 13 Figure 5.9 Summit area of Mt Ruapehu, 22 June 1969 showing eruption affects...... 15 Figure 5.10 Summit of Ruapehu showing Crater Lake and eruption affects, 2 November 1977...... 15 Figure 5.11 Ruapehu Crater Lake, A – 13 October 1981 showing a large sulphur slick on the lake surface. B – small phreatic eruption 28 December 1981...... 16 Figure 5.12 Views of small phreatic events in the Ruapehu’s Crater Lake, A – 21 January 1982; B – 11 February 1982...... 17 Figure 5.13 Eruptive activity through Ruapehu Crater Lake 24 September 1995...... 18 Figure 5.14 Strong ash emission from Ruapehu, 19 June 1996...... 19 Figure 7.1 Time series plot showing eruption scale verses time from 1830 to 2012...... 22 Figure 7.2 Cumulative number of eruptions from Ruapehu, 1830 to 2012...... 22 Figure 7.3 Cumulative frequencey (red dots) and frequency (blue squares) plot of Ruapehu eruption scale data post 1940...... 25 Figure 7.4 Cumulative frequencey (red dots) and frequency (blue squares) plot of Ruapehu eruption scale data, excluding the 1945 and 1995/1996 eruptive episodes...... 27

APPENDICES APPENDIX 1: DETAILED ERUPTIVE OBSERVATIONS AND NARRATIVES ...... 33 A1.1 1830s ...... 33 A1.2 1850s ...... 33 A1.3 1860s ...... 33 A1.4 1870s ...... 37 A1.5 1880s ...... 38 A1.6 1890s ...... 52 A1.7 1900s ...... 66 A1.8 1910s ...... 73 A1.9 1920s ...... 74 A1.10 1930s ...... 75 A1.11 1940s ...... 77 A1.12 1950s ...... 81 APPENDIX 2: SUMMARY OF ERUPTIVE AND LAHAR ACTIVITY AT RUAPEHU FROM 1830 TO 2012 ...... 83

APPENDIX FIGURES

Figure A 1.1 Map illustrating the summit of Ruapehu (Hill, 1891)...... 53 Figure A 1.2 Sketch of the Crater Lake area provide in Hill (1891)...... 54 Figure A 1.3 G Allen’s 9 March 1894 sketch of the Crater Lake area...... 56 Figure A 1.4 George Frederic Allen sketched this view of Mt. Ruapehu on 10 March 1895, the day it erupted...... 57 Figure A 1.5 An illustration of Ruapehu in eruption, printed in the Illustrated Australian News (1 April 1895)...... 63 Figure A 1.6 Ruapehu Crater Lake as published in the Auckland Weekly News 8 May 1902 (p.2)...... 67

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Figure A 1.7 Otago Witness 8 May 1907: The Crater Lake on Ruapehu recently in violent eruption...... 72 Figure A 1.8 Ruapehu Crater Lake, Photographs taken circa 1920s by W H Thorley...... 74 Figure A 1.9 Image of Ruapehu Crater Lake reproduced in the Auckland Weekly News 20 May 1936 (p.48)...... 76 Figure A 1.10 Image of Ruapehu summit area reproduced in the Auckland Weekly News 20 May 1936 (p.48)...... 76 Figure A 1.11 Copy of the painting made by Ashley Cunningham of the 31 March 1945 eruption he and friends witnessed (Cunningham, 2000)...... 78 Figure A 1.12 View of the ash cloud from the eruption of Mt Ruapehu, from near Waihohonui Hut, during a deer hunting expedition...... 79 Figure A 1.13 Aerial view of the crater, Mt Ruapehu, photographed by Whites Aviation in August 1947...... 80 Figure A 1.14 This panorama shows the swollen lake in Labour weekend 1953, about two months before the Tangiwai disaster in December 1953...... 81

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ABSTRACT

In recent years considerably more interest has been taken in aspects of the hazards presented by volcanic eruptions and the risk to people who may be affected by the eruptions. Several works have used statistical approaches to look at these problems. A significant shortfall of these studies is the completeness of eruption catalogues. This report presents a new look at eruptive activity at Ruapehu and attempts to create a more complete catalogue of activity.

The major focus has been on extracting eruption observations from historic newspaper collections (1861 to 1960), detailed unpublished scientific reports, published papers, parliamentary reports and popular writings. The focus has been on filling the gaps between the larger and more significant events that previous compilations have recorded. Many aspects of small scale activity remain unreported. The eruption activity catalogue is now made up of observations of activity on 603 days since 1830.

Five scales of eruptive active are defined and several periods of enhanced activity, lasting from one year eight months to over seven years are now recognised at Ruapehu. The long term eruption recurrence rate using all the data (post 1830) for scale 3 and above events is 1.79 events per year, while using post 1940 data this is 4.00 events per year. The 1945, 1966-1982 and 1995-1996 eruptive activity strongly influence this result. When the 1945 and 1995-1996 activity is excluded the annual eruption recurrence rate for scale 3 and above events is 0.49 events per year.

KEYWORDS

Mt Ruapehu, Ruapehu volcano, eruption history, eruptions, lahar

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1.0 INTRODUCTION

In a review article by Mr Malcom Ross in the Otago Witness (5 June 1907) he outlines the attractions of the Tongariro National Park (TNP) and makes this summary: “The first ascent was made by Messrs John and Thomas Allison in December, 1877, but they, went only to the North Peak [Te Heuheu]. Two years later Messrs Beetham and Maxwell made the ascent, and continuing along the summit, discovered the Crater Lake. Since then various ascents have been made, and it is interesting to note the varied experiences of the different climbers in regard to the Crater Lake. In 1881 Mr and Mrs Birch and Mr Arthur Russell saw steam, arising from it. In 1886 Mr Park, FGS, found the lake frozen over. Three months after Mr Park’s visit Mr Lawrence Cussen found the lake boiling. Again, in 1890, Mr H. Hill (of Napier) saw the lake in a state of intense activity. Mr Lowe, Government Surveyor, saw the lake boiling during his ascent in 1895. Great explosions were taking place, and steam was also issuing from holes in the old ice-filled crater near the lake. In 1898, when I ascended the mountain, there was no activity in the Crater Lake, and what from down below we took to be steam coming from the top of the mountain, proved to be simply volcanic ash blown over the ridge by a strong wind. Similarly, I believe casual observers often say that the mountain is steaming when in reality only ashes or wisp of clouds are being blown over its crest. For many years Ruapehu was generally believed to be an extinct volcano, but it will be seen from the fore going that there is ample evidence to prove that it is still active”. He was correct!

Recently techniques have been developed to better assess the likelihood of eruptive activity (Sparks and Aspinall, 2004; Marzocchi et al., 2008) and the risks that the activity poses to visitors or staff and scientists working on a volcano (Jolly et al., 2010; Sandri et al., 2010a). This has also been applied at other volcanoes like White Island (Scott et al., 2004; Jolly et al., 2007) and Auckland (Lindsay et al., 2010; Sandri et al., 2010b). A major constraint on these analyses is the completeness and accuracy of the datasets used to compile the frequency and scale of eruptive activity.

Aspects of significant eruptive activity at Ruapehu volcano have been compiled and are presented for example in Gregg et al. (1960), Cole and Nairn (1975) and Latter (1985). These only focussed on the ‘major’ phases of activity or larger discrete events. Latter (1985) compiled a more complete dataset for his analysis of the frequency of eruptions in New Zealand. Wilson (2009) used data from the NZ Volcano database post 1950 based on Crater Lake visits. Gregg (1964) and Houghton et al. (1987) have discussed hazards.

Recognising the shortfalls in these datasets and the need for more complete data to enable the new hazard assessments to be better used, this project was undertaken to improve the completeness of the Ruapehu eruptive activity catalogue. The major focus has been on historic newspaper collections, detailed unpublished scientific reports, published papers, parliamentary reports and popular writings. Some of the focus has been in filling the gaps between the larger and more significant events previous compilations have recorded. Many aspects of small scale activity remain unreported. The eruption activity catalogue is now made up of observations of activity on 603 days since 1830.

For completeness, near full quotes from many references to activity from the 1830s to 1959 are included as an appendix so readers are able to see the quality of the observations and the assessment that is used to quantify the level of eruptive activity. All observations are also presented in table form as Appendix 2. Also extracted from these data is a list of days with lahar activity (Table 6.1).

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2.0 DATASETS

The motivation for this study was the increased interest in risk and hazard assessments, and the knowledge that the traditional summaries of eruptive activity like Gregg et al. (1960) and Cole and Nairn (1975) were generalised and did not list all activity. Access to many old datasets like newspapers, Parliamentary and Department reports has changed significantly in recent years and this greatly assisted in compiling this report. Significant ashfall activity associated with the 1945 eruptive episode is presented in Johnston (1997a), while Johnston et al. (1998) and Johnston et al. (2003) summarise ashfall during the 1995/1996 eruptive episode. Manville and Hodgson (1998) and Manville (2003) summarise lahars.

In this study newspaper accounts (1861 to 1960) have been one of the major sources of new data. Newspaper articles provided a wealth of information, but care is needed about the accuracy and validity of some of the reports. There are many examples where different dates are assigned to the same ‘apparent’ event. This appears to be due to the larger newspapers (i.e., New Zealand Herald, The Dominion) frequently reprinting (at a later date) stories first printed in local papers, without altering the text, for example using the phrase ‘yesterday’. The date of an event is often inferred to have occurred later than it actually did. Where possible these duplications have been corrected for. Other data sets include published references of activity and sources like annual Department and Parliamentary reports have been searched to obtain details of activity from 1830 to 1960. Post 1960 reports are based on documents in the former NZ Geological Survey (NZGS) files (T20/500 series). Items are referenced by the publication date and name of the newspaper, the DSIR report number on the file document (e.g., RUA 64/02) or the publications in Appendix 2.

The eruption history narratives are grouped by decade with near full transcriptions of most accounts in Appendix 1. The accounts are reproduced so future workers can easily see the sources, without having to locate the original articles in collections. The activity observations gathered from these sources are summarised in table form in Appendix 2 with references to the sources.

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3.0 CLASSIFICATION OF ACTIVITY

To be able to classify the wide variety of historic activity that has occurred at Ruapehu a classification of eruptions has been developed to scale the levels of activity. The first attempt to look at activity was by Hurst (1981), but no table of eruptive activity was presented. Houghton et al. (1987) proposed five classes (Table 3.1) when they conducted their evaluation of volcanic hazards from Ruapehu. These were based on the approximate area of the zone at extreme risk and the range of fall ejecta.

Table 3.1 Magnitude scale for hazard zones established for historical eruptions at Ruapehu and return periods, after Houghton et al. (1987).

Magnitude Area of Risk Zone Range of Ejecta Return Period (m2) (m) (yr) 1 <103 <102 1 2 103-104 102-103 2 3 104-105 103-104 5 4 105-106 104-105 9 5 >106 >105 18

Following the 1995 and 1996 eruptions of Ruapehu, Sherburn et al. (1999) modified the table to accommodate the observed effects or on-going activity (Table 3.2). This analysis was based on activity from 1971-1996 but restricted only to the days of Crater Lake visits.

Table 3.2 Semi-quantitative estimate of the size of Ruapehu eruptions based on observed effects, after Sherburn et al. (1999).

Size Observed Effects 1 Small phreatic eruptions confined to lake. Phreatic eruptions accompanied by surges, material deposited outside Crater Lake, but still 2 confined to crater basin. 3 Deposition of material outside the crater basin; possible lahars in Whangaehu catchment. 4 Larger lahars; more material deposited outside of crater basin. Lahars in catchments other than Whangaehu: material deposited more than a few kilometres 5 from Crater Lake.

Wilson (2009) adopted the Sherburn et al. (1999) table with negligible modification (Table 3.3). There is little acknowledgement in this and the Sherburn et al. (1999) table for other eruptive phenomena (i.e., explosive ash eruptions). Again observations were restricted only to days when the Crater Lake was visited.

Table 3.3 Semi-quantitative estimate of the size of Ruapehu eruptions based on observed effects, after Wilson (2009).

Magnitude Observed Effects 1 Small phreatic eruptions confined to Crater Lake. Phreatic eruption accompanied by surges; material deposited outside Crater Lake, but still 2 confined to the crater basin. 3 Deposition of material outside the crater basin; possible lahars in Whangaehu valley. 4 Larger lahars: more material deposited outside the crater basin. Lahars in valleys other than the Whangaehu: material deposited more than a few kilometres 5 from the vent.

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For this analysis it was found necessary to make minor modifications to take better account of eruptive activity not previously accounted for. This is primarily ash emissions when there is no Crater Lake present, like in 1945 and the latter stages of the 1995 and 1996 eruptions. Also there is more inclusion of the areas affected (Table 3.4) and they have been labelled as an ‘eruption scale’. For completeness Dam Break events are also distinguished in the table.

Table 3.4 Semi-quantitative estimate of the scale of Ruapehu eruptions based on observed effects (modified from Houghton et al., 1987; Sherburn et al., 1999 and Wilson, 2009). Eruption column heights are above the active vent.

Eruption Observed Effects Scale

Crater Lake steaming, hotter than normal (i.e., above 30-35°C) creating additional interest, but 0 no observations (or confirmation) of activity in lake.

1 Small phreatic eruptions confined to Crater Lake.

Phreatic or pheatomagmatic eruption accompanied by surges; material deposited outside 2 Crater Lake, but still confined to the crater basin. May produce larger flows/floods in Whangaehu Valley.

Deposition of material outside the crater basin; possible remobilisation/lahars in upper 3 catchments and Whangaehu valley; OR small scale explosive eruptions/intermittent ash emission when no lake is present.

Material deposited well outside the crater basin onto the summit plateau and outer flanks. 4 Lahars possible in several catchments; OR explosive ash eruptions when no lake is present producing columns up to 10000 ft.

Large scale explosive eruption displacing moderate volumes of the lake, lahars in all/most major valleys. The summit and slopes covered, with ashfall off the cone; OR explosive 5 eruptions when no lake is present producing tall (> 10000 ft) eruption columns and ashfall off the cone.

DB Dam Breaks, post eruption floods, landslides and glacier failures.

Note this only considers historic activity. The geological record indicates that stronger activity has occurred from Ruapehu. The connection between historic activity and events in the geological record have not been explored in this report.

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4.0 DATA SET COMPLETNESS

In Appendix 2 activity has been recorded at the daily level, that is if more than one event has occurred on a given day it is summarised for the day. This is because many of the older accounts are less complete than more recent ones and some form of standard unit of time is need to be able to plot the activity. This particularly affects the way some minor levels of activity are recorded. When using catalogue type data for frequency and magnitude analysis it is important to understand the completeness of the data set and how that may impact on any other analysis.

For this compilation the data has been rounded to the day level and this impacts on the number of events recorded for the smaller scale activity. For example in the late 1970s through to early 1990s small scale geysering (phreatic) activity was commonly observed and is reported here as a single event or more correctly scale of eruption for the day. However observers often reported observing several events during their time in view of the Crater Lake (1-5 hours of observation). The activity is therefore classed as a single event when compiling numbers, this clearly underestimates the occurrence of these events. However it does characterise the style and size of activity for the day.

As the main driver for this compilation is to record the relative frequency of different size eruptions (and hence the risk it poses on the volcano), it is felt this approach is justified. A single larger eruption if observed would see the scale score for the day raised. The volcano has not been observed every day, nor for 24 hours of any day.

As a guide to the completeness of the data a cumulative frequency verses eruptive scale plot is presented in Figure 4.1, based on 603 observation days. There is drop off in the number of expected days displaying activity below eruptive scale 3 and is very marked for scale 2 or less activity, which appear to be underrepresented.

Figure 4.1 Cumulative frequencey (red dots) and frequency (blue squares) plot of Ruapehu eruption scale data post 1830.

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5.0 ERUPTION NARRATIVE

In this section a summary of eruption descriptions is presented based on the more full transcripts and data in Appendices 1 and 2 and referenced publications. It appears that the first accounts of eruptive activity relate to an unknown date in the 1830s. The source appears to be the same in the two published accounts in 1895, which note the last activity was 60 years previously and lasted several years. There are no accounts or references of activity in the 1840s. Mead (1970) points out a reference to a ‘crater with hot springs’ in February 1853 (i.e., no lake), been based on Grey’s ascent of the mountain. This was eight years before the 1861 dam break flood. If no lake was present in 1853 this could imply the time required to fill the crater basin with water is of the order of a decade, consistent with post 1945 and 1995. Mead (1970) also reports an account indicating the Crater Lake was of considerable size about this time (1860s), which is shortly before the 1861 event.

A very significant break out lahar event occurred on 13 February 1861. A decline in the river flow was noted hours beforehand and the peak flow was sustained for 3-4 hours (Wellington Independent, 5 March 1861). Many observations that followed tended to suggest a glacial failure, for example one account mentions an exceptional hot summer. Of interest are three other observations. The first related to the water quality: this was noted to change from pure to mineral water after the 1861 lahar, suggesting Crater Lake water didn’t enter the Whangaehu catchment before the break out. The second refers to an account from a Maori chief which indicates the lake was larger (pre break out). The third is significant eruptions in May 1861 (3 months later) with reports of ash columns and incandescence, suggesting the February event may be related to unrest before the May eruptive activity. Graettinger et al. (2010) note the lack of Crater Lake sediment in the 1861 deposit as one of its characteristics, but do list brick-red and black scoria and andesitic lithics as its predominant lithology. The same lithology forms the right abutment of the current lake outlet today. This lithology is also present in the 1975 lahar deposits. Mr H Murray in his account of an ascent in 1882 also discusses the likelihood of a hot lake contributing to the 1861 event.

After the May 1861 eruptive activity, nothing is noted until 1869 with accounts of hot ashes melting snow (January) and flooding in the Whangaehu River, then red glows in October. The October activity led to a general exodus of the Maori living near the mouth of the Whangaehu River (lahar threat?). There are also accounts of the mountain throwing out immense clouds of steam in 1869 and some later accounts refer back to 1869 as the first known activity (Cowan, 1927).

There are no accounts of eruptive activity in the 1870s, except for the mention of ash on the snow in January 1870; this is likely to mark the end of the activity in 1869. There are references to steam being observed at the end of 1880 and again in 1881. A hot lake was observed during an ascent in 1882 and estimated to be about 800 m across. The lake is reported as frozen over in January 1886 and the crater basin was estimated to be only 200 m across.

In April 1886 the lake is estimated to be only 150 m across and was reported to be in ‘a boiling state’. There are numerous accounts of activity through May, June and July 1886 and some debate about the correctness of the reporting. Many predate the Tarawera eruption, so we can discount ‘post Tarawera eruption association’. A letter to the Wanganui Chronicle (29 July 1886) reports the Whangaehu River has become ‘clear and pure’ while the Waikato has turned ‘turbid’. This would suggest there may have been lahar activity affecting the drainage on the Rangipo fan. This is also discussed again in August 1886 in the Wanganui Herald. There are further accounts of activity in September 1886, which are again disputed by some.

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Steam columns and eruptions are reported in April, May and June 1887. An illustration of Ruapehu in eruption was published in October 1887 (Figure 5.1) but no accounts of activity have been noted.

An account of an eruption and lahar on 22 April 1889 are published in May and June 1889 and also an account of a large lahar on 29 April. Further activity on 1 May is reported as an enormous geyser. An ascent shortly after this, reports thick blue mud covering the snow. Further activity is reported in June when geysers at regular intervals are reported, in August sudden floods are noted and again in December 1889. There are many references to changes in the Whangaehu River during this time, suggesting frequent lahar activity.

Figure 5.1 The volcano of Ruapehu, Province of Auckland, NZ. Picture as featured in the Illustrated Australian News (October 15, 1887).

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An account of an ascent in March 1890 reports the Crater Lake in a very agitated state. Cowan (1927) recounts the observations of Mr Ross (proprietor Terraces Hotel) and states in 1890 that he witnessed an eruption. An account of an ascent in January 1891 reports ‘dense black smoke issuing from the crater’. This account is difficult to reconcile as there was a lake present, so maybe a misreporting from Ngauruhoe or just steam plumes. Immense volumes of steam (plumes) are reported in February 1892. In March 1894 the lake is reported as a beautiful green, with sulphurous deposits on the surface and apparently cold.

However by April 1895 it was milky and steaming and the first recorded temperature was obtained by surveyor Dunnage (Thomson, 1926), being 53°C (128°F). A photograph taken on 5 April 1895 (Figure 5.2) shows a calm lake with a prominent snow covered bench on the north side. Quiet vigorous eruptions were observed earlier in March 1895 (Figure 5.3), lasting several days and may account for the lowered lake level. The Wanganui River was reported as discoloured on 11 March, indicating lahars were being generated in the northern and/or western catchments as well. Accounts of an ascent on 18 March indicate there was no lake, while a couple of days later climbers reported it was belching forth gigantic rocks in the direction of Tokaanu. Some accounts also suggest ashfall was common. Hill is quoted in November 1895 in accounts of visits to the Crater Lake, confirming geysering in the lake and eruption deposits. The date of the climb is not clear. An article published on 12 May 1936 (Evening Post) reports the Mangatoetoenui and Manga-nui-a-te-Ao had mud and sludge in them as a result of the March 1895 eruptions.

It would appear that the Crater Lake did not start overflowing again until 1896 when a large fish kill is reported in the Whangaehu River. A tepid and slightly steaming Crater Lake is reported in April 1897, along with an H2S odour. Activity is next noted in August 1897 when Ruapehu is reported emitting a dark ‘smoke’. In September the lake was all boiling up and of a yellow-blue colour; it was estimated to be 7.6 m (25 ft) below overflow. They also reported numerous impact craters. Three ‘separate upheavals’ are reported in December 1897.

A cold lake with ice floating in it is reported in March 1898. Further eruptions occurred on 31 August 1899 ‘sending up an immense volume of eruptive matter’ through the day. Activity is not reported again until January 1903 when ‘puffs of smoke and rumbling’ are noted. Gregg et al. (1960) reports an eruption in 1903 that produced a lahar in the Whangaehu. An article which appears on 30 May 1903 discussing the railway indicates lahars are known in the Mangatoetoenui and Manga-nui-a-te-ao rivers.

Two newspapers carry stories in March 1904 of sulphur stench and heavy smoke, attributing this to Ruapehu. There are no other accounts to support this. An eruption is reported in April 1905 (Figure 5.4). A larger eruption on 15 March 1906 ejected considerable amounts of lake bed and had ballistic blocks. However in January 1907 the lake is described as ‘not steaming perceptibly’ and the snow is reported to be discoloured (? March 1906 debris).

Two to three days of activity are reported at the end of February 1907 when immense volumes of steam were reported. A coach driver describes the activity on 10 April 1907 as a ‘great mass of dark matter’. Discoloured snow is then seen on 16 and 18 April 1907, with steam columns in following days. After April 20 there are reports of large landslides and avalanches that have changed the summit outline on the Ohakune side. The Skate Glacier is ‘much broken’ in one account. The lake is described as steaming later in April and eruption deposits are confirmed. There are further indications of activity in early May 1907 and again in July (Figure 5.5). All discussion indicates the 1907 activity is smaller than the 1895 eruptions.

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Figure 5.2 View of Ruapehu Crater Lake on 5 April 1895 (Lands and Survey, 1895). Note the exposed bench near the lake shore, constent with the reported activity in March 1895.

Figure 5.3 Image of Ruapehu in eruption 10 March 1895, reproduced in the supplement to the Auckland Weekly News 29 March 1906 (p.4). Sir George Grey Special Collections, Auckland Libraries, AWNS-19060329-4-4.

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Figure 5.4 View possibly from Waiouru showing eruption cloud over Mt Ruapehu, 28 April 1905. Photographer unknown, GNS Science (GNS) VML 103416.

Figure 5.5 Otago Witness 8 May 1907: “The Crater Lake on Ruapehu recently in violent eruption”. The lake is surrounded by walls of ice, about 200 ft in thickness. The crevassed glacier in the foreground leads down towards the source of the Wangaehu River. (Photographer Mr Malcom Ross).

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A further small eruption is noted in early March 1908 and strong sulphur fumes are noted later in the month. A steaming but lukewarm lake is reported in December 1908. Thomson (1926) reports geyser activity in March 1909. Eruptions are again reported in early February 1910, however there are also several accounts disputing these. An account of a climb (assumed to be in late 1910) reports evidence of recent eruptive activity. No further activity is reported until late June 1918 and October 1921, when tall steam columns lasting one day are reported for each date.

In February 1925 there are two reports of activity and ‘high tide marks’ in the Whangaehu River. This is attributed during the Tangiwai enquiry to a collapse of the ice cave (Stillwell et al., 1954). Thompson (1925) reports a new source for the Whangaehu River, higher on the mountain, and also lowered water level in the Crater Lake due to the ice cave being enlarged. Strong steaming is reported for March. In a newspaper interview with Blyth in 1926 he is quoted:

“indicating a very cold, but not frozen lake. It also summarises several earlier climbs indicating the lake was warming from 1920 to 1922, being warmest in 1922 and cooling since then”.

There is no mention of any eruptive activity during that period. Cowan (1927) reports an account from August 1926 stating the lake was frozen over. While Thompson (1927) reports:

“the water in the Crater Lake is still cold on the surface and will probably freeze again this winter. The lake was frozen over last year for the first time on record for the past thirty years or more”.

Thompson (1928) reports a slight rise in the lake temperature compared to the previous year and in 1930 the cold lake present since the eruption of Ngauruhoe in 1926, had become hot again (Thompson, 1930).

A small eruption and steam columns are noted in June 1934, while an eruption not getting out of the lake basin is reported on 11 August 1934. The Crater Lake changed colour following this event. Another event is reported in December 1934 and February 1935. A further moderate sized eruption is reported on 9 May 1936 and images are published in the Auckland Weekly News of the Crater Lake (Figure A 1.9 and Figure A 1.10). Robertson (1937) presents a fuller account of water level changes and the eruption date. Further activity is reported in April 1940 that produced dark streaks on the glacier and Pare-te-tai-tonga. Guides then reported snow for about a mile was covered in blue mud, in places over 6 inches deep. An eruption covering Girdlestone and the Mangaehuhu Glacier is reported on 10 August 1942. Then mud and stones are reported from Dome to Cathedral Rocks in late September 1944. Another eruption is reported in October 1944. No other activity is reported before March 1945, when a major eruption episode started.

Moderate to large phreatomagmatic eruptions which start on 8 March mark the onset of the eruptive episode, which continued on 9 and 10 March. By 19 March a ‘lava cone’ was emerging from the lake. This is destroyed by eruptions from 22 to 26 March and further eruptions are noted on 31 March, 1, 2, 15 and 16 April. No lahars are reported1. Then in May as another island appeared more explosive activity is recorded (5 to 14 May) with ashfalls reported. More ash producing eruptions started on 17 June and continued to month’s end when the lava extrusion displaced the lake. Ash eruptions are noted most days through July to late August and into September and October. What are possibly the strongest events are

1 The Strachan family recounted to Harry Keys during the lead up to the March 2007 break out flood, damage to a bridge in 1945 by lahars.

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noted on 6 November and activity continued to near year’s end marking the end of the eruptive episode. A lakelet is first noted on 18 December 1945 by Healy (1956), being a bright yellow-green in February 1946.

Ash eruptions are reported in April 1946, while minor eruptions through the lake are reported at the end of May 1946 and again in June. Geysering is observed in the lake in July. Poor weather restricted observations in September and October, only steam emissions are reported. In January 1947 a larger lake is observed (Figure 5.6). Isolated eruptive activity is reported in February, March and April when ash columns and impact craters are reported, while an event in May discoloured the snow. Further isolated eruptions are reported on 23 January, 6-10 February and 1 May 1948. Later accounts only refer to a steaming lake.

The next confirmed eruptive activity is in June 1950 when discoloured snow is observed. One eruption is reported for March 1951, while ‘typical’ phreatic eruptions like one in July 1952 are described at the Tangiwai enquiry. This implies they were frequent during this time. Steam columns and surging are observed in October 1954. On the evening of 24 December 1953 a dam break flood occurred from the Crater Lake and damaged the Tangiwai rail bridge allowing Wellington to Auckland express K626 to derail into the river. 151 lives were lost. In October 1956 steam columns are reported. A small event on 18 November is reported to have discoloured snow, but this is later discounted by Lloyd. A phreatic eruption is next reported on 28 January 1958. Starting May 1959 steam and ash are reported and again in June and this may have continued until late August.

High water levels are reported in the Whangaehu River in April 1964, with observations of a hot (50°C) lake and steam columns on May 19. Steam columns are reported again in June 1964. Steam columns reappear in March 1966 and an eruption is inferred in April when the Whangaehu River pH drops. In July and August expanded lava fragments and fresh pumice bombs are reported, small scale phreatic activity is observed and reported through to October 1966 (Figure 5.7 and Figure 5.8).

Figure 5.6 Aerial view of the crater, Mt Ruapehu, photographed by Whites Aviation in August 1947. Ref: WA- 08904-F. Alexander Turnbull Library, Wellington, New Zealand.

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Figure 5.7 Strongly steaming Crater Lake, 25 July 1966. Photo: J Healy, GNS VML 103437.

Figure 5.8 Fresh low density lava fragment that was found in the outlet area, 3 August 1966. Photo: EF Lloyd, GNS VML 103538.

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Similar activity occurs again in July and September 1967. Strengthening eruptions in April 1968 produce small lahars and local ash on the snow, getting larger later in the month. Similar small scale events are common during May and June with ash. There were possibly more in October. A major phreatomagmatic eruption follows on 22 June 1969, marking the climax of this eruptive cycle (Figure 5.9).

A small scale eruption through the lake occurred on 16 September 1970. From April to November 1971 numerous small-moderate scale phreatic eruptions and minor lahars are very common. Minor phreatic events are reported in October-November 1972 and January 1973. Several small phreatic events are observed in October-November 1973 and again in January 1974. This style of event is very common most days in March, with rare events in April and May 1974. A larger event on 2 August is followed by more small events over the next few days. An isolated event is seen in October.

Major phreatomagmatic eruptions producing moderate lahars in many catchments and ashfall occurred on 24 and 27 April 1975. Evidence of a smaller event is noted in October 1975 and again in March, May, September and November 1976. Evidence of small phreatic events or observations are reported in July, August and October 1977. A moderate lahar- producing eruption follows on 2 November with smaller events later in the month and one in January 1978 (Figure 5.10). A moderate eruption producing ashfall for 2 km downwind follows on 7 March 1978. Several small phreatic events are seen in June, and again in September and October, some leaving ash on the snow. Similar minor activity is observed in January, June July and August 1979. A larger event in December leaves ash on Pyramid Peak. Late January through February sees several small events and isolated ones in March and April 1980.

Eruptions producing minor ashfall on the snow are reported in October and November 1980 and then again in late October and November 1981 with smaller events in December 1981 (Figure 5.11). January, February and March 1982 are characterised by numerous small eruptions contained within the lake (Figure 5.12). No further activity is reported until May 1985 when similar small events are observed. Further small discrete events are noted in June, October and November 1985 and February 1986.

Small phreatic events restart in late August 1987 and continue for a few days. Similar events occur in March and April 1988. A moderate eruption on 8 December 1988 produces a small lahar and deposits ash up to 1.1 km from the lake. Small scale activity follows in January and February 1989, with more small events in July. January, February and June 1990 see similar activity including blocks floating on the lake surface. Activity restarts in February 1992 and ends in early March. Similar activity is noted in March 1994 and again in January-February 1995, accompanied by very high lake temperatures. Stronger activity occurs in April and May 1995 with a moderate eruption producing ash on the snow in June and a lahar. Two small events are seen in July 1995.

The largest eruptive episode since 1945 starts on 18 September 1995 with lahar producing events that grew in size during the month and continuing into October (Figure 5.13). The Crater Lake is removed by powerful eruptions on October 11 and frequent ash producing explosions follow through to months end. A crater lake starts to reform after November 1995. In April 1996 a portion of the crater rim collapses onto the Whangaehu Glacier and into the lake. The landslide on the Glacier propagates into a small lahar. The reforming Crater Lake is ejected by powerful eruptions on June 17 1996 and explosive ash producing eruptions follow through June, into July and August (Figure 5.14). Several of these are very strong. Further small eruptions occur in September 1996. After September a lake starts to reform again on the crater floor.

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Figure 5.9 Summit area of Mt Ruapehu, 22 June 1969 showing eruption affects. Photo: J Healy, GNS VML 104712.

Figure 5.10 Summit of Ruapehu showing Crater Lake and eruption affects, 2 November 1977. Photo: EF Lloyd, GNS VML 105574.

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Figure 5.11 Ruapehu Crater Lake, A – 13 October 1981 showing a large sulphur slick on the lake surface. B – small phreatic eruption 28 December 1981. Photos: P van der Werff, GNS VML 107010; IA Nairn GNS VML 107219.

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Figure 5.12 Views of small phreatic events in the Ruapehu’s Crater Lake, A – 21 January 1982; B – 11 February 1982. Photos: BJ Scott GNS VML 107146; IA Nairn GNS VML 107227.

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Figure 5.13 Eruptive activity through Ruapehu Crater Lake 24 September 1995. Photos: DL Homer, GNS VML 7859, 3224.

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Figure 5.14 Strong ash emission from Ruapehu, 19 June 1996. Photo: DL Homer GNS VML 3550.

Minor eruptions occurred through the new lake in October and November 1997. Some small events also occurred in January 1998 and one in November. Minor activity is reported in the lake during September and October 1999. Steam representing what may have been a small event was seen on 13 September 2005. A small phreatic eruption occurred on 4 October 2006, which was contained to the lake basin. A larger eruption on 25 September 2007 produced lahars in the Whangaehu and Whakapapa valleys, ballistics and minor local ashfall. A small event on 13 July 2009 produced snow slurry lahars in the upper Whangaehu Valley.

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6.0 LAHARS

Many of the eruptive events identified above and summarised in Appendix 2 have produced lahars or significant floods off the volcano. As these present a significant hazard at Ruapehu, they have been highlighted from the data set and compiled in Table 6.1. At least fifty seven days with lahar activity are identified and there are three Dam Break events (1861, 1953, 2007).

Table 6.1 Summary of eruptive activity that has or may have produced lahars at Ruapehu. Three Dam Break events are also listed for completeness.

Date Comment

1861 February 13 Dam Break: Appears as a lake break out event, bridge destroyed

1869 January Floods in Whangaehu River

1886 July Changes in the Whangaehu and Waikato Rivers

1889 April Events 22 and 30 April

1889 June 1 River flow decreases (Wangaehu)

1889 August Flood in Whangaehu River

1889 December Flood in upper Whangaehu Valley

1895 March 10 Flood in Whangaehu River and others (Wanganui discoloured)

1903 March 1 Flood in Whangaehu River

1907 April 15 Reports of avalanches/collapses, but no lahars

1925 February 3 Flood in Whangaehu River

1940 April Floods reported

1945 March Many eruptions; Bridge damaged at Strachans, no other lahar details

1953 December 24 Dam Break: Tangiwai break out flood (151 lives lost)

1964 April Reports of water level changes in Whangaehu

1966 April 4 pH drop in Whangaehu River

1968 April 26 Flood in Whangaehu River

1968 April 27 Smaller flood in Whangaehu River

1969 June 22 Major lahar producing eruption

1971 April 3 Flood in Whangaehu River

1971 May 8 Flood in Whangaehu River

1971 May 16 Flood in Whangaehu River

1971 May 19 Surging through the outlet

1971 May 21 Surging through the outlet

1971 June 18 Surging through the outlet

1971 July 3 Surging through the outlet

1971 July 4 Surging through the outlet

1971 July 14 Surging through the outlet, Whangaehu Valley

1974 March 29 Surge marks at the outlet; small eruptions common all month

1975 April 24 Major phreatomagmatic eruption. Lahars

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Date Comment

1975 April 27 Phreatomagmatic eruption. Lahars

1975 October 4 or 17 Surge marks at the outlet

1976 May 5 Evidence of higher lake levels

1977 early July Evidence of surge through outlet

1977 November 2 Moderate phreatomagmatic eruption, lahar down Whangaehu valley

1988 December 8 Moderate phreatic eruption, small lahar down Whangaehu valley

1995 June 29 Phreatic/phreatomagmatic eruption

1995 July 4 Evidence of surge thru outlet

1995 September 18 Moderate phreatomagmatic eruption, lahar down Whangaehu valley

1995 September 20 Moderate phreatomagmatic eruption, lahar down Whangaehu valley

1995 September 23 Moderate phreatomagmatic eruption, lahar down Whangaehu valley

1995 September 24 Phreatomagmatic eruption, possible lahars

1995 September 25 Phreatomagmatic eruption, possible lahars

1995 September 26 Phreatomagmatic eruption, possible lahars

1995 September 27 Phreatomagmatic eruption, possible lahars

1995 September 28 Phreatomagmatic eruption, possible lahars

1995 September 29 Phreatomagmatic eruption, possible lahars

1995 October 6 Phreatomagmatic eruption, possible lahars

1995 October 7 Phreatomagmatic eruption, possible lahars

1995 October 11 Phreatomagmatic eruption, lahars as lake is removed

1996 April Rim collapse producing small lahar on Whangaehu Glacier

1996 June 17 Major phreatomagmatic eruptions with lahar down Whangaehu valley

1997 November 3 Minor phreatic eruptions, small lahar

1997 November 4 Minor phreatic eruptions, small lahar

2007 March 18 Dam Break: Flooding in Whangaehu Valley

2007 September 25 Moderate hydrothermal eruptions, lahars down Whangaehu and Whakapapa

2009 July 13 Phreatic activity, snow slurry lahar

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7.0 DISCUSSION

This compilation documents over 600 days with eruptive activity from Ruapehu in the last 180 years. When the eruption scales are plotted with time (Figure 7.1 and 7.2) several periods of enhanced eruptive activity are apparent after 1830. It is very subjective how these are defined as the start and end of the periods are difficult to pick.

A detailed statistical analysis is beyond the scope of this compilation as is the addition of monitored parameter data, however when calculating recurrence rates etc. it may be necessary to know if you are within a period of enhanced activity or not. Periods like 1895, 1903-1910, 1945, 1966-1982 and 1995-1996 are easy to define visually in Figure 7.1 and Figure 7.2. Listed below in Table 7.1 are several other periods that also appear to be discrete periods of enhanced activity. These have only been identified visually.

Figure 7.1 Time series plot showing eruption scale verses time from 1830 to 2012.

Figure 7.2 Cumulative number of eruptions from Ruapehu, 1830 to 2012.

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Table 7.1 List highlighting periods of enhanced eruptive activity that have been identified visually from the data set. No. Obs. is the number of observations and Max. is the largest eruption scale factor in the period. Highlighted periods are the eruptive episodes.

Date Duration No Max. Comment Obs.

1 April 1886-June 1887 1 y 2 m 13 2 Small events

2 April-December 1889 9 m 5 3 Geysering and lahars

3 March-April 1895 2 m 4 5 Major eruptive event

4 August-December 1897 5 m 3 3 Eruptions, deposits on summit

5 January 1903-December 1910 7 y 11 m 15 3 Cluster of eight periods with activity

6 February-July 1907 6 m 4 3 Subset of #5: eruption deposits

7 June 1934-February 1935 9 m 4 2 Steam eruptions

8 October 1944-July 1946 1 y 10 m 140 5 Major eruptive episode

9 February-May 1947 4 m 6 5 Ash eruptions

10 January-May 1948 5 m 6 4 Ash eruptions

11 October-November 1956 2 m 2 3 Small eruptions through lake

12 May-August 1959 4 m 5 3 Small explosive eruptions

13 April-June 1964 3 m 6 3 Possible lahar producing event

14 March 1966-March 1982 6 yr 136 5 Cluster of over 10 periods of enhanced activity

15 March-October 1966 8 m 11 2 Subset of #14: small phreatic events

16 April-June 1968 3 m 8 4 Subset of # 14: small eruptions, lahars

17 June 1969 1 d 1 5 Subset of # 14: major eruption

18 April-November 1971 8 m 31 4 Subset of # 14: numerous eruptions

19 October 1972-January 1973 4 m 3 2 Subset of # 14: small events

20 October 1973-October 1974 1 yr 18 3 Subset of # 14: small-moderate events

21 April 1975 3 d 2 5 Subset of # 14: major eruption

22 October 1975-November 1976 1 yr 1 m 6 3 Subset of # 14: small events

23 July 1977-January 1979 1 yr 6 m 20 4 Subset of # 14: small-moderate events

24 June 1979-April 1980 10 m 14 3 Subset of # 14: small events

25 October-November 1980 2 m 2 2 Subset of # 14: small events

26 October 1981-March 1982 6 m 17 3 Subset of # 14: small events

27 May 1985-February 1986 1 yr 9 2 Minor events and activity

28 August 1987-June 1990 2 yr 11 m 34 4 Numerous minor events, one moderate, lahar

29 February-March 1994 2 m 5 1 Minor events

30 January 1995-September 1996 1 yr 8 m 117 5 (x2) Two major eruptions

31 October 1997-January 1998 4 m 13 3 Minor-moderate eruptions

32 September-October 1999 2 m 1 1 Minor events

33 October 2006 1 d 1 2 Small eruption

34 September 2007 1 d 1 4 Moderate eruption

35 July 2009 1 d 1 2 Small event

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Five periods of greater than one year duration are identified:

• January 1903-December 1910

• October 1944-July 1946

• March 1966-March 1982

• August 1987-June 1990

• January 1995-September 1996

Two sub-periods within the March 1966 to March 1982 period are longer than a year. All the scale 5 eruptions except the 10 March 1895 event fall within a longer duration period of enhanced activity.

As these data will be used to inform risk analysis, it is important to be confident in the completeness of the data set. As discussed above and shown in Figure 4.1 the completeness appears to drop off very quickly below eruption scale 3 events, that is scale 2 and smaller events appear to be significantly underrepresented (Table 7.2). As the data set from 1940 may be considered more complete (515 observations), these data have also been analysed for completeness (Table 7.3 and Figure 7.3).

Table 7.2 Frequency distribution for all eruptive activity observations post 1830 (181 years).

Scale Number Cumulative

5 28 28

4 121 149

3 171 320

2 86 406

1 171 577

0 26 603

Table 7.3 Frequency distribution for all eruptive activity observations post 1940 (72 years).

Scale Number Cumulative

5 27 27

4 118 145

3 143 288

2 67 355

1 149 504

0 11 515

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Figure 7.3 Cumulative frequencey (red dots) and frequency (blue squares) plot of Ruapehu eruption scale data post 1940.

From these data an eruption recurrence rate can be calculated for each scale of eruption recognised for this work. However the Scale 0 and 1 cannot be considered as they are not full counts of the number of events, they just represent the maximum event size known for the day. Hence only data for eruption scale 2 and larger are considered for the following eruption recurrence rates (Table 7.4) and post 1940 (Table 7.5).

The eruption scale 2 events are of a size that would affect people working in the outlet area; they are represented most recently by the October 2006 activity. Scale 3 events are larger, but do not create lahars outside of the Whangaehu Valley (i.e., surging through the outlet); they were common in 1971 (occasionally affecting people) and during the stronger phases in 1945 and 1995 as the lake was removed. The scale 4 events are ones that produce lahars in several catchments and significantly affect the entire summit area. The most recent example is the eruption on 25 September 2007.

Another way to look at these data is: what is the typical background level of activity that is outside of known major eruptive episodes. The definition of eruptive episodes is uncertain but the 1945 and 1955/1996 eruptions are recognised as the two largest sustained periods of eruption at Ruapehu in the recorded history. The 1966-1982 period (Figure 7.2) also stands out as very active, but is included as the Crater Lake was not removed at that time. For this analysis the eruption episodes have been defined as between September 1944 and July 1946 and June 1995 to November 1997, giving 165 observations of days with activity at eruption scale 2 or greater over (Table 7.6 and Table 7.7). Frequency distributions are shown in Figure 7.4.

I have also removed eruptions from the 1945 and 1995/96 episodes to examine the effects of these periods on the eruption frequency – magnitude distributions (Table 7.7). The 1945 and 1995/1996 eruptive episodes have a significant impact on the eruptive frequency, being about 65% of the observations. Any analysis of frequency will have to consider the current state of the volcano and the objectives of the analysis.

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Table 7.4 Eruption recurrence rates for the 1831 to 2012 data set (181 years).

Scale Background Background Background Recurrence Interval Recurrence Interval Recurrence Interval Per Month Per Three Months Per Year

2 0.04 0.12 0.48

3 0.08 0.24 0.94

4 0.06 0.17 0.67

5 0.01 0.04 0.15

All: 2 and above 0.19 0.56 2.24

All: 3 and above 0.15 0.44 1.77

All: 4 and above 0.07 0.21 0.82

Table 7.5 Eruption recurrence rates for the 1940 to 2012 data set (72 years).

Scale Background Background Background Recurrence Interval Recurrence Interval Recurrence Interval Per Month Per Three Months Per Year

2 0.08 0.23 0.93

3 0.17 0.50 1.99

4 0.14 0.41 1.64

5 0.03 0.09 0.38

All: 2 and above 0.41 1.23 4.93

All: 3 and above 0.33 1.00 4.00

All: 4 and above 0.17 0.50 2.01

Table 7.6 Frequency distribution for all eruptive activity observations post 1830, excluding the 1945 and 1995/1996 eruptive episodes and greater than scale 2.

Scale Number Cumulative

5 4 4

4 25 29

3 57 86

2 79 165

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Table 7.7 Eruption recurrence rates for the 1830 to 2012 data set (177 years), excluding the 1945 and 1995/1996 eruptive episodes.

Scale Background Background Background Recurrence Interval Recurrence Interval Recurrence Interval Per Month Per Three Months Per Year

2 0.04 0.11 0.45

3 0.03 0.08 0.32

4 0.11 0.04 0.14

5 0.002 0.006 0.02

All: 2 and above 0.08 0.23 0.93

All: 3 and above 0.04 0.12 0.49

All: 4 and above 0.01 0.04 0.16

Figure 7.4 Cumulative frequencey (red dots) and frequency (blue squares) plot of Ruapehu eruption scale data, excluding the 1945 and 1995/1996 eruptive episodes.

In summary the long term eruption recurrence rate using all the data (post 1830) for scale 3 and above events is 1.79 events per year, while using post 1940 data this is 4.00 events per year. The 1945, 1966-1982 and 1995-1996 eruptive activity strongly influence this result. When the 1945 and 1995-1996 activity is excluded the annual eruption recurrence rate for scale 3 and above events is 0.49.

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8.0 REFERENCES Allen, L.R. 1948 Activity at Ngauruhoe, April-May 1948. NZ Jou Sci and Tech 30/3:187-193. Beck, A.C. 1950 Volcanic activity at Mt Ruapehu from August to December, 1945. NZ Jou Sci and Tech 31/5; 1-13. Bryan, C.J.; Sherburn, S. 1999 Seismicity associated with the 1995-1996 eruptions of Ruapehu volcano, New Zealand: narrative and insights into physical processes. Journal of Volcanology and Geothermal Research, 90(1/2): 1-18. Bryan, C.; Sherburn, S. 2003 Ruapehu 1996, Volcano-Seismic activity. In Volcano and geothermal observations 1996. NZ Volcanological Record 25. Institute of Geological & Nuclear Sciences science report 2003/27. Cole, J.W.; Nairn, I.A. 1975 Catalogue of the active volcanoes and solfatara fields of New Zealand. Rome, Italy: International Association of Volcanology and Chemistry of the Earth’s Interior. Catalogue of the active volcanoes of the world including solfatara fields 22. 156 p. Cowan, 1927 The Tongariro National park, New Zealand. Tongariro National Park Board, Wellington. 156 p. Crawford, J.C. 1870 Recollections of travels in NZ and Australia: 131. Cussen, L. 1886 The triangulation of the King Country. Appendix 2 J House Representatives. NZ C-1A: 13-14. Cussen, L. 1887 Thermal activity in the Ruapehu Crater. Trans NZ Institute 19:374-80. Cunninghan, A. 2000 Fiery Adventures, In Tongariro the Annual. V9. Department of Conservation. Dunnage, W.H. 1895 In Lands and Survey Annual report to Parliament 1895. p 171-173. Field, H.C. 1896 On Volcanic and Seismic Phenomena. Transactions and Proceedings of the Royal Society of New Zealand. V29:615. Friedlaender, B. 1898 Some notes on the volcanoes of the Taupo District. Trans NZ Inst 31:498-510. Girdlestone, H.E. 1909 The mountains of the Tongariro National Park. In Department of Lands and Survey annual report, Appendix IV. Appendix to the Journals of the House of Representatives of New Zealand, C.1, pp.41-45. Graettinger, A.H.; Manville, V.R.; Briggs, R.M. 2010 Depositional record of historic lahars in the upper Whangaehu Valley, Mt Ruapehu, New Zealand : implications for trigger mechanisms, flow dynamics and lahar hazards. Bulletin of volcanology, 72(3): 279-296. Gregg, D.R. 1964 Volcanic risk from the Tongariro volcanoes. New Zealand journal of geology and geophysics, 7(1): 106-107. Gregg, D.R. 1971 James Hector’s visit to Tongariro in 1867 : note. New Zealand journal of geology and geophysics, 14(2): 414-415. Gregg, D.R.; Grange, L.I.; Williamson, J.H.; Hurst, J.A.; Clark, R.H.; Wilson, S.H. 1960 The geology of Tongariro subdivision. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey bulletin 40. 152 p. Healy, J. 1956 New Zealand. In report of the standing committee on volcanology. Proc 8th Pacific Science Congress II: 27-30. Healy, J.; Lloyd, E.F.; Rishworth, D.E.H.; Wood, C.P.; Glover, R.B.; Dibble, R.R. 1978 The eruption of Ruapehu, New Zealand, on 22 June 1969. DSIR Bulletin 224 pp79. Hector, J. 1887 Presidential address. Trans NZ Institute 19:462-470. Hill, H. 1891 Trans NZ Institute 24:603-624.

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Hill, H. 1895 Ruapehu and the Volcanic Zone in 1895. Transactions and Proceedings of the Royal Society of New Zealand. V 28. Houghton, B.F.; Latter, J.H.; Hackett, W.R. 1987 Volcanic hazard assessment for Ruapehu composite volcano, Taupo Volcanic Zone, New Zealand. Bulletin of volcanology, 49: 737- 751. Hurst, A.W. 1981 Pattern recognition applies to temperature and chemical measurements of Crater Lake, Ruapehu. DSIR Geophysics Division Report 181. Johnston, D.M. 1997a Physical and social impacts of past and future volcanic eruptions in New Zealand. PhD thesis, Massey University. Johnston, D.M. 1997b A chronology of the 1945 eruption of Ruapehu volcano, New Zealand. Institute of Geological & Nuclear Sciences science report 97/2. Johnston, D.M.; Rosenberg, M.; Houghton, B.F.; Thordarson, T.; Scott, B.J. 1998 Distal Ash Falls: Physical and Social Impacts. NZ Volcanological Record 24: 21-29. Institute of Geological & Nuclear Sciences science report 98/3. Johnston, D.M.; Scott, B.J.; Rosenberg, M.; Houghton, B.F. 2003 Ruapehu 1996; Distal Ash Falls. NZ Volcanological Record 25: 16-24. Institute of Geological & Nuclear Sciences science report 2003/27. Jolly, G.E.; Sandri, L.; Lindsay, J.; Scott, B.J.; Sherburn, S.; Jolly, A.D.; Fournier, N.; Keys, H.; Marzocchi, W. 2010 Volcanic risk metrics at Mt Ruapehu, New Zealand : some background to a probabilistic eruption forecasting scheme and a cost/benefit analysis at an open conduit volcano. abstract EGU2010-2994 In: European Geosciences Union General Assembly 2010, Vienna, Austria, 2-7 May 2010. Goettingen, Germany: Copernicus Gesellschaft. Geophysical research abstracts 12. Jolly, G.E.; Scott, B.J.; Smith, W.D. 2007 Quantitative assessment of volcanic risk for activities on White Island. GNS Science consultancy report 2007/48. iii, 7 p. Keys, H.R. 1998a Volcano watch: Ruapehu still restless. In Tongariro the Annual V6:12-15. Keys, H.R. 1998b Volcano watch. In Tongariro the Annual V7:26. Keys, H.R. 1999 Volcano watch 1999. In Tongariro the Annual V8:12-16. Keys, H.R. 2006 Volcano watch 2005. In Tongariro the Annual V14:52-56. Keys, H.R. 2007 The 18 March lahar- a preliminary report. In Tongariro the Annual V15:27- 29. Lands and Survey. 1895 Annual report to Parliament .p 171-173. Latter, J.H. 1985 Frequency of eruptions at New Zealand volcanoes. Bull of the NZ National Soc for Earthquake Engineering V18:55-110. Lennard, l.M. 1945 The Crater Lake: A historical survey. The Ruapehu Ski Club 9(1). P 15. Lindsay, J.M.; Jolly, G.E.; Sandri, L.; Marzocchi, W.; Holland, G. 2010 New probabilistic hazard assessment tools for mitigating volcanic risk in Auckland, New Zealand. p. 401- 409 (paper 048) In: Williams, A.L.; Pinches, G.M.; Chin, C.Y.; McMorran, T.J.; Massey, C.I. (eds) Geologically active : delegate papers 11th Congress of the International Association for Engineering Geology and the Environment, Auckland, Aotearoa, 5-10 September 2010. Boca Raton, Fla: CRC Press. Lowe, H.J. 1897 New Zealand. Department of Lands and Survey. Appendix to the Journals of the House of Representatives of New Zealand, C.1, pp.114-115. Manville, V.R. 2003 Ruapehu 1996: Lahars. In Volcano and geothermal observations 1996. Lower Hutt: Institute of Geological & Nuclear Sciences Limited. Institute of Geological & Nuclear Sciences science report 2003/27; New Zealand volcanological record 25. 74 p.

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Manville, V.R.; Hodgson, K. 1998 Ruapehu 1995: Lahars. In Volcano and geothermal observations 1995. Institute of Geological & Nuclear Sciences science report 98/03; New Zealand volcanological record 24. 115 p. Marzocchi, W.; Selva, J.; Sandri, L. 2008 Probabilistic Volcanic Hazard Assessment and Eruption Forecasting: The Bayesian Event Tree approach , in Conception, verification and application of innovative techniques to study active volcanoes, Ed. W. Marzocchi and A. Zollo, ISBN 978-88-89972-09-0. Mead, W.P. 1970 Memories of a mountain and river. Nairn, I.A. and the Ruapehu Study Group 1998. Ruapehu 1995: An overview. NZ Volcanological Record 24. Scott BJ and Sherburn S compilers. Institute of Geological & Nuclear Sciences science report 98/3. Nairn, I.A.; Wood, C.P.; Hewson, C.A.Y. 1979 Phreatic eruptions of Ruapehu: April 1975. New Zealand Journal of Geology and Geophysics, 22(2): 155-73. Oliver, R.L. 1945 Further activity of Mount Ruapehu, May-July 1945. NZ Jou of Sci and Tech 27/1:24-32. Park, J. 1887 Narrative of an ascent of Ruapehu. Trans NZ Institute 19:327-331. Paterson, B.R. 1976 The effects of lahars from the 1975 April Mt Ruapehu eruption and the threat of future eruptions in Tongariro Power Development. NZ Geological Survey Engineering Geology Report EG 230. Reed, J.J. 1945 Activity at Ruapehu, March-April, 1945. NZ Jou Science and Technology 27/1:17-23. Robertson, W. 1937 Public Domains and National Parks of New Zealand, annual report on. Department of Lands and Survey. House of General Assembly C10. Sandri, L.; Jolly, G.E.; Lindsay, J.; Scott, B.J.; Sherburn, S.; Jolly, A.D. 2010a Volcanic risk metrics at Mt Ruapehu : an attempt to set up a probabilistic eruption forecasting scheme and a cost/benefit analysis at an open conduit volcano. p. 16 In: Jolly, A.D.; Keys, H. (Eds) Tongariro Day: a workshop to discuss scientific advances at the Tongariro National Park volcanoes, Department of Conservation Turangi, 29 October 2009: abstracts. Lower Hutt: GNS Science. GNS Science miscellaneous series 32. Sandri, L.; Jolly, G.E.; Lindsay, J.; Howe, T.; Marzocchi, W. 2010b Combining probabilistic hazard assessment with cost-benefit analysis to support decision making in a volcanic crisis from the Auckland Volcanic Field, New Zealand. abstract EGU2010-2337 In: European Geosciences Union General Assembly 2010, Vienna, Austria, 2-7 May 2010. Goettingen, Germany: Copernicus Gesellschaft. Geophysical research abstracts 12. Scott, B.J. 2003 Ruapehu 1996, an eruption narrative. In Volcano and geothermal observations 1996. NZ Volcanological Record 25. Institute of Geological & Nuclear Sciences science report 2003/27. Scott, B.J.; Manville, V.; Hancox, G.T.; Smith, W. D.; Hoverd, J.L. 2004 Assessment of the risk posed by the Crater Lake, White Island. Institute of Geological & Nuclear Sciences science report 2004/28. Sherburn, S.; Bryan, C.J.; Hurst, A.W.; Latter, J.H.; Scott, B.J. 1999 Seismicity of Ruapehu volcano, New Zealand, 1971-1996 : a review. Journal of volcanology and geothermal research, 88(4): 255-278. Skey, W. 1869 On the water from the Whangaehu River, Onetapu, Auckland. Trans. NZ Inst. 1:28. Sparks, R.S.J.; Aspinall 2004 Volcanic activity and challenges in forcasting prediction and risk assessments. In The State of the Planet: Frontiers and Challenges in Geophysics Geophysical Monograph 150, IUGG Volume 19.

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Speight, R. 1908 In: Cockayne, Botanical Survey of the Tongariro National Park. N.Z. NZ Parliamentary Paper C.11 7-13. Stilwell, W.F.; Hopkins, H.J.; Appleton, W. 1954 Tangiwai Railway Disaster. Report of Board of Inquiry. 31 p. Thompson, J.B. 1925 Tongariro National Park, annual report of the board. Department of Lands and Survey. House of General Assembly C13. Thompson, J.B. 1926 Tongariro National Park, annual report of the board. Department of Lands and Survey. House of General Assembly C13 Thompson, J.B. 1927 Tongariro National Park, annual report of the board. Department of Lands and Survey. House of General Assembly C13. Thompson, J.B. 1928 Tongariro National Park, annual report of the board. Department of Lands and Survey. House of General Assembly C13. Thompson, J.B. 1930 Tongariro National Park, annual report of the board. Department of Lands and Survey. House of General Assembly C13. Thompson, G.H. 1954 Evidence to Tangiwai Railway Disaster V2; 297-301. Thomson, J.A. 1926 Volcanoes of New Zealand, A record of eruptions. NZ J Sci Tech 8:354- 371. Wilson, G.M. 2009 Monitoring at Ruapehu volcano; can eruptions be predicted? BSc Hon thesis, University of Canterbury. P79.

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APPENDICES

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APPENDIX 1: DETAILED ERUPTIVE OBSERVATIONS AND NARRATIVES

In this section of the report relatively full copies of many of the accounts of eruptive activity are presented. This is to allow readers to review the quality of reports without having to retrace all the original accounts.

A1.1 1830S

The Feilding Star (12 March 1895) carries this short comment:

“A native resident of Aorangi informs us that it is sixty years [1830s?], judging by the recollections of the older men, since Ruapehu gave signs of activity. At that time and for many years fire, smoke and ashes came from it, but not with any force”.

The Star (21 March 1895) reports:

“The reported activity of Mount Ruapehu, in the centre of the North Island, is significant, not on account of the violence of the outburst, but because of the fact that for sixty years, this snow-clad mountain had given no sign of volcanic energy, beyond the existence of a warm lake half-way between the surrounding plain and its summit. About sixty years ago, according to the recollection of aged Maoris, Ruapehu was an active volcano, entitling ashes, fire and smoke; but the action was feeble, and from that time until a week ago the mountain was quiescent, though the neighbouring hill, Tongariro, was always more or less active”.

No other activity is known for the 1830s or 1840s.

A1.2 1850S

Mead (1970) comments about a footnote missed in the English edition of Hochstetter’s book on New Zealand geology, related to an ascent of Ruapehu by Sir George Grey on 2 February 1853. Grey informed Hochstetter he had seen ‘a crater with hot springs’. There is no direct reference to a Crater Lake, but implies at least an active crater was present.

A1.3 1860S

In Mead’s (1970) compilation he recounts a story from a nursing sister who climbed the mountain in 1908. During her visit she met an old chief of Karioi who recounted to her how he had climbed the mountain as a boy. When shown photographs, from the surveyor Snow, of the lake he commented the lake he saw was bigger than in Snow’s photograph. Mead suggests this may have been before the great lahar of 1861, when the flood, carried great blocks of ice right down to the sea.

The first popular account that can be attributed to Ruapehu appears to be the destruction of a bridge by a lahar on 13 February 1861. The Taranaki Herald (2 March 1861) quoting the Wanganui Chronicle (14 February 1861), recounts the following account of the destruction of the Whangaehu bridge:

“The Wellington mail did not arrive yesterday till 8 pm, in consequence of a heavy flood in the Wangaehu, which carried away 150 feet of the south end of the bridge. The river rose very rapidly yesterday morning between 6 and 7 o’clock, bringing down large masses of ice and snow, and a great quantity of heavy

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timber. At 7 o’clock the bridge gave way, and in about two hours’ afterwards the river had returned to its usual channel, leaving hundreds of tons of mingled snow, ice, and clay stranded on the banks”.

The Wellington Independent (5 March 1861) reports:

“Wangaehu Bridge — We regret to state that the bridge over the Wangaehu river, on the line of road between Wanganui and Rangitikei was destroyed on Wednesday morning, the 13th Feb., by a most unexpected and unprecedented rush of snow from the mountains. It appears that the Maoris living by the river side had noticed at daybreak an unusual decrease of water in the river, as though the stream had been somewhere checked, and at about six o’clock am, was seen an immense body of what in the distance appeared like solid ground filling up the river from bank to bank and extending for more than a hundred yards along its bed; this enormous mass which proved to be composed of ice, snow, and great tree trunks closely packed into a solid body, moved slowly on towards the bridge, where its progress was for the moment arrested; forced on however, by the weight of water which followed and the accumulated material, it was soon raised to the level of the platform of the bridge, which was wrenched up from the piles, and then with a tremendous crash platform and piles gave way leaving a free course for the floating mass. For three or four hours afterwards the water remained almost as high as the level of the bridge, carrying down huge blocks of ice, black masses of snow, and rotten timber; towards evening, however, the river had fallen again to within a foot of its usual height, though even then lumps of ice were swimming down in the muddy water, …No previous instance is on record among the Maoris of any similar occurrence; the inhabitants of the little pa by the river side were terribly frightened, and rushed out from their wharies exclaiming that Tongariro was coming down upon them, and indeed it would appear as though a tremendous avalanche had precipitated en masse the contents of one of the snow filled ravines of that mountain, into the river bed”.

A further account in the Taranaki Herald (30 March 1861):

“The flood which carried away the Wangaehu Bridge on the 13th, being one of a very unusual kind, demands a further notice in our columns … It is most probable that the long continuance of hot weather caused a large portion of this cliff to be detached, of sufficient bulk to arrest the course of the river, and form a temporary lake, which gradually rose in height, until its barriers, no longer able to resist the pressure, gave way, when the whole volume of water rushed along with immense impetuosity, carrying large blocks of ice and snow with it, and all the timber it met with in its course. The river rose fully 12 feet, overflowed the banks, and deposited large quantities of these debris along its entire course, until it reached the bridge … The flood came down about 6 in the morning, and by 1 o’clock began to subside, leaving large masses of ice, snow, timber, and mud filled with crystals of ice on the banks. The day being intensely hot, these heaps produced a vapour which appeared like smoke. The lumps of ice were remarkably compact and heavy, and in such quantities as not to be entirely melted away four or five days afterwards”.

The Wellington Independent (25 February 1862) reports this account of a visit in 1862:

“We have been favoured by John Jordan Esq., of Koreromai-waho, Rangitiki, with the following notes of a journey … Amongst other things pointed out to us

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was the change in the course of the Wangaehu, which took place at the time that the bridge was washed away last year. The idea that a large avalanche was forced down the river bed by the water behind it is absurd, for the simple reason that the banks are so low that the water would have found an outlet round the sides.

The probability is, and this is supported by the account of the Maoris that a large avalanche did descend from the mountain side, and block up the course of the stream, that the force of the water, and the heat of the sun combined broke off large masses of ice, which were floated down and collected near the bridge …”

Crawford (1870) states:

“an avalanche from the top of Ruapehu piled up at a major bend in the Wangaehu and blocked it and that accumulated water broke through sweeping the debris downstream and destroying the bridge”.

A summary of activity in 1907 in the Bush Advocate (29 April 1907) reports:

“The River Wangaehu has its source in this lake, and its sudden flooding is always connected with geyser action on Ruapehu. This stream rose suddenly in 1863 [possibly should be 1861], an avalanche of snow and ice tearing along its course and carrying away a bridge”.

Following eruptions in 1895 the following account of 1861 was published by the Wanganui Herald (8 April 1895):

“Sir, The recent volcanic activity of Ruapehu has naturally caused much interest in this phenomenon, and consequently I have been asked by several of my friends to give an account of what I witnessed in the Wangaehu River either in the year 1860 or 1862 [=1861], I cannot locate the time nearer. The effects produced by, I presume, an almost similar outburst of the mountain which seems to have caused a sudden ejection of a vast quantity of sulphurous water from the crater.

In the midsummer of one of the year above mentioned I was one day visiting my brother, who lived on the right bank of the Wangaehu, and at the time of which I am about to speak I was standing on the bank of the river, and looking up along reach of the same about 30 chains, when I suddenly saw coming around the corner in the distance a huge wave of water and tumbling logs which filled the whole trough of the stream. I called out to my brother who was close by and together we witnessed its rapid approach. As it passed us it appeared to be covered with what we at first thought to be pumice, but the intense cold which soon made us shiver and turn blue, caused us to discover that what we had supposed to be pumice was no less than frozen snow; mixed with this was a continuous mass of logs and general forest debris. Very soon the Wangaehu Bridge passed us stuck in the roots of a giant tree, and a few minutes afterwards about a dozen canoes came down, some of them sailed along more or less straightly down the centre while others kept running into the banks and rebounding continuously. I caught the rope of one of these from the bank and instantly I was nearly pulled under, so rapid was the rush of the icy and sulphurous torrent.

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Previous to this outburst, that must be remembered by many old settlers, the water of the Wangaehu was perfectly pure. A couple of years before this occurrence Mr Gerse lived a mile or two higher up the river, and he has more than once told me that he had been in the habit of lowering a cask into a pool of the stream with a piece of fresh meat tied in it, and with the bung hole left open. When he required eels he lifted the cask by a rope attached to it, and always caught more than he could eat; this shows the then purity of the water. Ever since the flood in question the river has been more or less impregnated with diluted sulphurous acid and hot alum, as is said by some, and it does not contain a living fish. Some time after this I read in Humboldt’s Cosmos that rivers, having their source in volcanic regions, are subject to alternate periods of pure water and then volcanic waters, the periods lasting from 20 to 50 years or a longer time.

I was in hopes the cycle had come round and we might expect pure water again in the Wangaehu. We shall see. I have omitted to mention that during this flood, for many miles up the valley, all the sheltered and back water places were piled up as high as the banks with enormous heaps of logs — millions of them. I am. etc., H. Sargeant”.

The Wellington Independent (16 September 1869), Taranaki Herald (2 October 1869) reports on a paper read at a recent meeting of the New Zealand Institute, an interesting paper by J C Crawford, Esq. about the end of the year 1861:

“This district is high, the vegetation alpine, and the winter climate evidently severe Mr. Crawford attributes the accident by which the Wangaehu bridge was swept away, to an avalanche from Ruapehu, which dammed up the Wangaehu, until the accumulated water swept all before it”.

New Zealand Spectator and Cook’s Strait Guardian (8 June 1861) reported:

“Ruapehu volcano —This volcano, which has been quiescent for a period beyond the recollection of the oldest inhabitant, suddenly burst forth into full activity on the 16th ult. [May], when dense volumes of smoke were seen issuing from the crater, and at night a lurid glare was reflected by the heavens, considerably astonishing the natives”.

This is the first record of an eruption at Ruapehu.

Skey (1869), detailing some of the most interesting results of the work performed in the Colonial Laboratory during the last few weeks, comments on analysis from the upper Wangaehu River:

“It was down this river that the wonderful avalanche of ice and mud forced its way from Ruapehu to the sea, in 1863 [1861], scouring out the bed of the river, destroying a bridge, and doing great damage to the native cultivations.

The cause of the avalanche may no doubt be attributed to a sudden escape of vapours, from the same volcanic source that gives origin to the mineral waters”.

In the Wellington Independent (27 July 1869) reports:

“The first meeting of the second session of the New Zealand Institute held at the Colonial Museum on Saturday evening last, July 24 …

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It appears, indeed, that so lately as in 1863 [1861], an avalanche of ice forced its way for a distance of seventy miles from Ruapehu in the centre of this island to the sea by the Wangaehu River”.

These are the only accounts of this date (1863). It is suspected this date is wrong as both trace back to the Skey lecture, and should more correctly refer to the 1861 activity which was more widely reported.

Gregg (1971) refers to a visit by Hector in 1867 to the Park, but only describes eruptive activity at Ngauruhoe. There is mention of sketches of Ruapehu, but nothing relating to eruptions.

The Evening Post (13 October 1869) reports:

“The Wanganui Herald says that on Monday evening there was a general exodus of the Maoris living near the mouth of the Wangaehu; their object being to gain the hills, on account of the big wave the Pakeha said would come. Drays were even loaded with everything the Maoris could move, and a long stream of people was seen winding their way along the road on the other side of the Wangaehu River. We have not been informed how long they intend remaining in safe quarters”.

It’s not clear, but this could be related to a perceived lahar threat from ongoing eruptive activity.

The Hawke’s Bay Herald and Taranaki Herald (7 May 1889) report:

“It is worthy of note that, though this is the third recorded eruption of Ruapehu, until now very few people have believed in it as an active volcano, and have ascribed previous reports to the deceptive appearance of clouds resting on the summit. The first time was in 1869, when Mr RT Batley distinctly saw the mountain throwing out immense clouds of steam, and the second was in 1886, a few weeks before the Tarawera eruption; let us hope that this time it is not an omen of a similar disaster to follow”.

A1.4 1870S

The Wellington Independent (1 February 1870) reports a letter from Mr A Birch (Patea) dated 20 January that Dr Hector read to the Wellington Philosophical Society. The letter describes eruption deposits on the volcano:

“I wish to let you know of a singular change in the appearance of Ruapehu, a portion of which seems overlaid with ashes or some substance other than snow …The first time the change of appearance was noticed in the mountain was about the 12th”.

In June the Star (14 June 1870) carries a report from Dr Hector re eruptions of Tongariro and also comments on Ruapehu:

“Dr Hector informs us that in January last [1869] there appears to have been a discharge of hot ashes which melted the snow where they fell on the slopes of Ruapehu, and that in October a red glow was observed to be reflected from the clouds overhanging the cone”.

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Meanwhile the Daily Southern Cross (17 June 1870) quotes the same article to that in the Evening Post of 9 June.

An account of a climb of Mt Egmont reported in the North Otago Times (19 April 1872) comments:

“Ruapehu and the volcano Tongariro vomiting up its ‘black smoke are to be seen distinctly”.

This is taken that Ruapehu could be seen, and Tongariro (i.e., Ngauruhoe) was erupting ash.

A1.5 1880S

The Hawke’s Bay Herald (24 May 1892) carries a letter from Mr HC Fields re first ascents of the mountain and the observation of a lake, including these comments:

“This latter phenomenon had also occurred at the end of 1880, at which time the north-east peak of the mountain was emitting a great quantity of steam, as if hot all through; so that no doubt the lake was boiling then, though no one actually observed it”.

Surveyor Cussen (1887), while reporting the surveys in 1886 comments:

“Five years ago [1881], when triangulating on the Kaimanawa ranges I noticed a column of vapour arising from Ruapehu, in the position of the crater; but not knowing of the existence of the lake, I thought it must be cloud or fog rising out of one of the gorges of the mountain, although it seemed very like a column of steam”.

Following accounts of activity in June-July 1886 a Mr AH Murray writes about his ascent in 1882 Wanganui Herald (2 September 1886):

“Never shall I forget the first view obtained from the summit of Ruapehu, just in front is the huge crater with its lake of sulphur water. The crater is surrounded on three sides by cliffs or walls having an elevation of about one hundred feet …. snow and ice has a dip towards the crater of about thirty degrees, thus rendering it unsafe …. The lake is about half-a-mile across each way, the lip of which is about eight hundred feet below the peaks. The colour of the water near the edge is a dirty green, gradually changing to a beautiful bright green near the centre. The water contained in this lake is at boiling point. Small clouds of steam could be seen rising at various points near the centre, the steam moving slowly across to the cliffs on the east. A white scum or froth drifted from different parts, gradually forming into a circle and disappearing. There can be no doubt about the water of this lake being very hot. …. enormous quantities of snow and ice which are continually slipping into this huge caldron …. The east margin of the lake is the most wonderful, having about half-a-mile of cliffs and steep faces running north and south, the elevation of which is about eighty feet. These cliffs and rocks are covered with masses of sulphur or other sulphurous mineral deposits, the crystals of which glistened in the sun and sparkled like a thousand gems. The crystals on the cliffs are deposited by the hot vapors rising from the lake laden with silica, sulphur, and other mineral substances contained in solution ….. The Wangaehu River is fed from this sulphurous lake, the water from the lake percolating and flowing through cracks and fissures on the east side. This gives a safety valve to the lake. The Wangaehu River, after getting under the ridge, flows

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through great masses of ice and snow, which cool its water before it reaches the ravines down which it flows, if it were not for the hot water of the lake, the Wangaehu River would cease to flow, and its course down the mountain would become an immense glacier ….. Some twenty-five years back [1861] the lake must have been hotter than usual the Wangaehu, sending a large volume of hot water among the ice, sent down thousands of tons of loose rock and masses of ice, blocks of which were carried down the river a distance of eighty miles, carrying away the new bridge which had just then been erected across the Wangaehu ”.

The Timaru Herald (21 May 1883) carries a report of Mr JHB Nicholls (geologist and gold prospector) recent tour of the interior of the North Island, where he describes the origin of the Whangaehu River:

“to examine the sources of the Waikato and Wangaehu rivers. Both flow from the eastern side of Ruapehu near the same point. I found the latter rising from an extensive ice cave at an altitude of 7100 feet. There is a great flow of water of the colour of milk, strongly impregnated with alum and iron”.

Although he ascended the volcanoes, observations are not reported.

Park (1887) describes his ascent of the volcano on 8 January 1886:

“The crater proper, or what was probably the former vent, is situated not in the centre of the basin, but appears to be nearer to Parataetaitonga than the northern peaks. The vent, as far as could be judged from our high position, is probably ten chains (200 m) across. At this time it was occupied by a great sheet of ice, of a bluish colour and there was no appearance of steam or water”.

Hector (1887) in an address to the Wellington Philosophical Society 30 June 1886 comments:

“It is mentioned as if new that there is a lake on Ruapehu, but if they looked at the model of that mountain in the Museum that was made years ago they would observe the very lake. This lake was first described by Messrs’ Maxwell and Beetham, and steam is often seen rising from it, as if from a warm pool in cold weather. The fact of its being a lake surrounded by permanent snow and ice-cliffs proves that it must be affected by some local hot spring; but Mr Park, who observed it in January last from the top of Ruapehu, reports that it was then frozen over”.

The Evening Post (12 May 1936) reports observations from a surveyor who reported the Crater Lake ‘to be in a boiling state in 11 April 1886’ (see below).

In an article read before the Auckland Institute, 26th July, 1886 Cussen (1887) reports his 11 April climb, describing the Crater Lake as:

“Deep down in a crateral hollow of basin-like shape, its steep sides covered with perpetual snow and ice, is a pool of water of a greyish-cream or drab colour. From the trig-station we overlooked this lake, the peak on which we stood being the south-west portion of the old crater-lips which surround the lake. From its peculiar surroundings of snow and ice, it was difficult to estimate with any degree of accuracy the diameter of the lake, and time would not allow of a proper measurement. It appeared to me to be nearly of a circular form, and 500 feet or

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more in diameter. It was quite impossible to descend to the lake, except by the aid of a long rope, and even then the descent would be attended with danger and difficulty. When I got on the top of the peak I noticed little clouds of steam rising from the surface of the water. On watching more closely, the water appeared now and again to assume a rotatory movement, eddies and whirlpools passing through it from the centre to the sides, and steam flashing up from those eddies, leaving little doubt in my mind that the water was in a boiling state. Close to the water the sides of the crater are bare of snow, and appear to be formed of loose particles of rock and volcanic ash; above are steep inclines of snow, sloping in all directions towards the water and terminating in icy masses overhanging the lake”.

The Evening Post (19 May 1886), Taranaki Herald (19 May 1886) and the Wanganui Chronicle (19 May 1886) reported from Taupo, May 18:

“During the past week several residents of Tapuharaeru, 60 miles distant from Ruapehu, have witnessed at intervals immense volumes of steam issuing from the summit of the mountain, which at present is one mass of snow. The steam seemed to rise out of the side of the crater, which the natives say has been regarded as extinct from time immemorial”.

This story was also reproduced in Bruce Herald (21 May 1886).

A report of the Tarawera eruption in the Southland Times (11 June 1886) comments on Ruapehu:

“steam has been issuing from the crater of Ruapehu — a thing not known for years”.

While a report of a climb in the Marlborough Express (14 June 1886) confirms the activity:

“Mr Cussen, surveyor, says he was on the top of Ruapehu three weeks ago, when he saw steam issuing from the crater. A few days later he saw a column of steam fully 200 feet high. The natives said they had never known anything of the kind before, Ruapehu always being deemed extinct”.

Also on 14 June the Star reports an observation from near Tarawera:

“Away to the south, in the direction of Ruapehu and Tongariro, were numerous jets of steam. From Ruapehu was issuing a large column of steam”.

The Evening Post (14 June 1886) interviews Professor Hutton, asking about Ruapehu activity:

“You remember that a few weeks ago there was a report that Ruapehu was believed to be smoking. Well, that, of course, looks rather significant now in the light of what has occurred since”.

The interviewer asked whether, supposing Ruapehu to have been in eruption when the smoke was supposed to have been seen, this ought not to have afforded a kind of safety- valve, and rendered the chance of an eruption at Tarawera loss probable. To this Professor Hutton replied:

“Well no, I think it is very possible this outbreak at Tarawera has proved a safety- valve for Ruapehu. You must remember though is a great difference of level

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between the two mountains. It may be that the matter, seeking an outlet, found itself unable to ascend a point so high as Ruapehu, and so burst through the earth at Tarawera”.

The Wanganui Herald (14 June 1886) carries a discussion for the Wanganui residents about the possibility of Ruapehu eruptions based on observations of surveyor Cussen:

“In the present state of public anxiety respecting volcanic eruption … he was engaged on Ruapehu about 3 weeks ago, when he discovered that it was showing signs of activity. He spent some days near the trig station there, in pursuance of his work. In a crateral hollow he found a lake between five hundred and six hundred feet in diameter, which appeared to have a cloud of steam resting on its surface. While he was engaged in his work he asked the cadet, who, formed one of his party of five, to watch this cloud and shortly afterwards his attention was called to it, when the steam being moved by whirlpool could be distinctively seen to be rising. After he had left the mountain and while engaged lower down, he saw a column of steam rising fully 200 feet into the air. This he saw several times and on pointing it to some old natives they acknowledged that they have never heard of such a thing before; nor had any of them previously noticed the phenomena … if Ruapehu should burst out in flames the Wanganui River will be flooded fully 40 feet higher than usual. He says there are enormous ice fields on Ruapehu”.

While the Evening Post (14 June 1886) reported:

“Mr. Lawrence Cussen, of the Survey Department, who returned to Wanganui yesterday, with Messrs Buttler and Stevens, Land Purchase Commissioners, reports that three weeks ago he was at the top of Ruapehu, when he saw steam issuing from the crater. A few days later he saw a column of steam fully 200 foot high. The natives stated they had never known any thing of the kind to happen before”.

The Te Aroha News (19 June 1886) reports:

“Taupo (June 12) Steam has been issuing from the crater of Ruapehu, a thing not known for many years. Ruapehu a mountain 9,800 feet high is about 70 miles south of Wairoa and about fourteen miles from Tongariro”.

A similar account reporting Mr Cussen is also presented in the Nelson Evening Mail, 21 June 1886.

The North Otago Times (1 July 1886) carries a story from Rotorua dated 30 June:

“Ruapehu, which was always believed to be extinct, shows signs of life, emitting steam, smoke, and jets of fire on the north-western slopes (Wanganui side). Laurence Cussen, District Surveyor, was in the neighborhood of Ruapehu at the time of the Tarawera eruption, and confirms the statement that steam has since ascended from Ruapehu. He made the accent to the summit and states that there is a hot lake in the old crater, the level of the water being about 400 feet below the top. From this steam rises some hundreds of feet above the mountain, melting and displacing snow and ice, all of which thus contributes to the volume of water in the crater”.

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Mr WI Birch writes to the Hawke’s Bay Herald (6 July 1886) discounting the activity:

“Sir,— ln the Herald of the Ist inst. there is an extraordinary telegram from Auckland informing your readers, on the apparent authority of Colonel Macdonald, that there had been a volcanic outbreak of Ruapehu. On his way back from Kariri Colonel Macdonald stayed at my house, and as he did not mention it to me I hardly think he could have made such a statement. I have been on the summit and from one end to the other of Ruapehu, and am aware that the extinct crater on the southern end of the mountain is now a lake of warm sulphurous water, having precipitous ice cliff’s descending into it on its western side, and with a hot spring issuing from a bank of black cinders on its eastern side. Steam has frequently been seen rising from this spring, but in no great volume that I am aware of. This is the source of the river Wangaehu. Two of my shepherds live in full view of the mountain, about 20 miles from it, and I feel sure that no considerable eruption, even of steam, could have taken place without their seeing it. W I Birch. Erewhon, July 3rd, 1886”.

Discussion of a letter in the Wanganui Herald (9 July 1886):

“In a letter to the Post, Colonel McDonnell says ‘I see from the newspapers a fear prevails in Wanganui of a heavy flood, should the snow be suddenly melted from Ruapehu, … On the east, again, of Ruapehu is the source of the Wangaehu River, which is subject to heavy floods from the melting snow, so much so that some years ago a huge mass of ice descended the mountain with a roar and precipitated itself into the source of the Wangaehu, and was borne away, carrying all obstructions before it — a mighty mass. Nearing the bridge over the Wangaehu near Owens station it swept the bridge entirely away, so large was the mass of ice, trees, and stones; but the Wangaehu is very heavily flooded in most seasons’”.

However at the same time several newspapers carry a story of activity, Star (14 July 1886), Evening Post, (14 July 1886), The Grey River Argus (15 July 1886), Bay Of Plenty Times (15 July 1886) stating:

“Rochfort, Government Engineer, writing from Karioi, states that on the 7th he saw a column of steam rising from Ruapehu, and observed smoke coming from the same mountain. The natives in the vicinity are alarmed after the recent Tarawera eruptions”.

These reports lead to letters in the Wanganui Herald (16 July 1886):

“To the editor Sir, — Last night you published an extract from a letter I received from Mr Rochfort referring to steam rising from Ruapehu, and to-night, via your leader, you say — In the face of the extremely contradictory reports respecting the activity of Ruapehu, it is difficult to form an opinion as to whether or not there is any truth in the statement that steam was seen rising, and now, sir, I wish to make a protest against this. It is very unfair to Mr Rochfort, who is a keen and careful observer, He has been continually passing and re passing Ruapehu for some time back, knows well the difference between Ngauruhoe, Tongariro, and Ruapehu, and has I feel sure, been so close to these mountains that it would be impossible for him to mistake one for the other. It would be quite impossible for him to say he saw steam and smoke if he did not. Your argument against the possibility is poor. You gave the testimony of three gentlemen well-known to us,

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who state positively they have seen steam rising. One is a surveyor, who was on Ruapehu itself at the time another, a civil engineer, who is professionally engaged close to its base. Against the statements of these gentlemen you bring the fact that the Maoris have no tradition of these things having occurred before; and also that Dr Hector goes against the theory that the Tarawera affair is connected with the Ruapehu activity. They did not say it was. What has it to do with the fact? Again, are we not to believe these statements because some one in Taupo cannot see the steam? Why, he is on one side of the mountain, they on the other. My reason for giving you the first ‘local’ was because I thought that the information coming from such a reliable source would very much interest your readers ; and my reason for troubling you now is to object to your (I believe unintentionally) throwing discredit on those statements.— l am SH Drew”.

To which the editor replies:

“July 15th, 1886. Mr Drew has troubled himself about rushing into print over a matter that it is certainly not our intention to dispute — the credibility of Messer’s Cussen and Rochfort, both gentlemen are worthy of the utmost confidence and we never for a moment meant to impugn their veracity — but what we did wish to do was this, to point out that opinions varied as to the origin of this steam, and therefore it was desirable that a party should examine the mountain and report on what they see or find there. We are not concerned at present in expressing our own opinions as to whether Ruapehu is showing signs of activity or not — but we do think it necessary that there should be some confirmation of the fact — if fact it is — by those, who, by visiting the mountain itself, cannot possibly be mistaken.— (Ed; WH)”

On July 15 the Wanganui Herald publishes:

“Sir, Some remarks in your paper respecting the reported activity of Ruapehu and Ngauruhoe were copied into last night’s Wanganui Herald and as the subject is of interest at present, possibly a few comments on it may not be out of place. Till now, I never heard a whisper that the crater-lake on Ruapehu was of other than cold water, though I have heard it repeatedly described by several who have seen it. I do not, of course, assert that the water may not be warm because the points from which it is visible can only be reached in late summer or autumn, when slight steam would hardly be noticeable, and the lake itself is quite inaccessible. I can say, however, that I have never, during thirty-five years’ residence here, seen steam rising from that part of Ruapehu, while the vapour from Ngauruhoe is often visible in clear weather. When riding into Marton however, on the afternoon of the 17th ult., Mr W. Marshall and I saw a quantity of steam or smoke apparently rising from the north-eastern or eastern side of Ruapehu, and I pointed this out to two lady friends. I could not be perfectly sure that it might not proceed from Ngauruhoe, because the eastern side of Ruapehu was in shadow at the time but I judged it to proceed from the latter mountain, because it hid the north-eastern slope; while it seemed to me that had it risen from Ngauruhoe the slope would have been sharply defined in front of it. I afterwards learned that the vapour had been observed by the postmaster at Marton and by many persons in Wanganui. The only clouds visible at the time were the vapour in question and the steam from Rotomahana, which last I saw again from here twice this afternoon. The place, Owhaoko, from which Colonel McDonald says he saw steam or smoke and jets of fire proceeding from

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Ruapehu, is about twenty-five miles E,S.E. of the range, so that the three peaks, Ruapehu, Ngauruhoe, and Tongariro, show separately at some distance apart, and it would be impossible to mistake the peak from which the signs of action emanated. The lake crater, too, is behind the mountain from there. I happen to know that the portion of Ruapehu from which the indications proceeded is not extinct, because I myself saw it smoking about four years ago [1882] when ascending the mountain. Maoris say that during the night of the 9th and 10th ultimo, Tongariro was roaring tremendously, and the great wave which rushed across Taupo Lake to Tapuaeharuru a day or two after the Tarawera eruption must apparently have proceeded from some upheaval in the vicinity of Tongariro or Ruapehu. My own conviction is that when the country between Ruapehu and Egmont becomes known it will be found that the volcanic zone extends continuously to the latter. Even now it is known, that there are at least two great volcano masses in the interval, which the Native traditions assert to have been dropped by Egmont in his flights to the sea coast. I am, H. C. Field”.

The Wanganui Herald (17 July 1886) reports new steam columns above the volcano:

“we publish the following extract from a letter received today by Mr Drew from the Rev. A Towgood, of Marton, who says, ‘lt will interest you to learn that I saw, just after sunrise this morning and also after breakfast, steam projected up from between the central peak and the south-eastern one of Ruapehu. The steam kept filling up the space between the two peaks and the back or northern peaks, something in the shape of an inverted bowl, and then disappeared into detaching wreath across the western peaks of the mountain. The steam seemed to come swelling up from within the peaks of the mountain like water from an over- brimming well …There were no clouds in the sky. Mr HC Field also informs us that yesterday morning, while driving down to town, he observed a cloud of steam drifting above Ruapehu at the south-eastern end, and is of opinion that there is something unusual going on in that locality’”.

Mr George Allen writes to the Wanganui Chronicle Herald on July 20 (published 21 July 1886):

“Sir, l find on my return here, after a fortnight’s absence; that the question as to whether steam has recently been issuing from the main crater of Ruapehu is still being discussed. I have been much indisposed to believe the correctness of the statements in the affirmative, knowing how easily ordinary clouds may be mistaken for steam issuing from a volcano. But on Friday, the 9th instant, I distinctly saw at 12.02, and at 12.12, noon, large puffs of steam arise from the great central crater of Ruapehu. The first of these had cleared off before the second arose. After the second, volumes of steam hid the summit for about two hours, when gradually dissipated. After that time, the western shoulder of Ruapehu was obscured by thin clouds of steam, or smoke, apparently coming from Auruhoe, or Ngauruhoe, the usually active crater of Tongariro. I saw what I have been describing from a hill about 1200 feet high, about 80 miles southeast of Paratetaitonga, the nearest peak of Ruapehu to Wanganui. I had opportunities of observing for over three hours with the theodolite telescope. My assistants were equally convinced with myself that what we saw at 12.02, 12.12, and for two hours after, was steam proceeding from the main crater of Ruapehu, and not from Auruhoe. George Allen. Wanganui, July 20, 1886”.

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Then on 21 July 1886 further observations are reported by the Wanganui Herald:

“Mr HC Field drew our attention this morning to an undoubted column of steam issuing from the north western end of Ruapehu. The steam seemed to be puffing up from a depression or saddle near the place indicated, and a strong field glass distinctly defined the character of the vapour, which could be seen puffing upwards from the saddle in question, until it joined a cloud of vapour which hung above it, and was kept replenished for several hours by the column of ascending steam. Whether the steam was being expelled from Ruapehu itself or one of the hills behind it we are not able to say, but Mr Field assured us that it could not be from either Ngauruhoe or Tongariro. Since writing the foregoing, Mr Drew, to whom we spoke on the subject, has taken further observations through a powerful glass, and states that there are several jets of steam issuing from a ravine at the western end of Ruapehu, part of which mountain forms a back ground to the lower jets, thus proving conclusively that the eruption is from Ruapehu, and not the usually active cone behind it”.

This is further reported in the Hawera & Normanby Star (23 July 1886):

“The Advocate reports that on Tuesday puffs of steam were seen by a number of persons in Marton rising from the central crater of Ruapehu. …Wednesday night’s Herald says: Mr HC Field drew our attention this morning to an undoubted column of steam issuing from the north western end of Ruapehu … Ruapehu, part of which mountain forms a back ground on the lower jets, thus proving conclusively that the eruption is from Ruapehu, and not the usually active cone behind it and debated in a report in the Nelson Evening Mail (18 August 1886) by the surveyor general. The annual report on the New Zealand Surveys gives the usual details of the work done during the year. The most interesting feature in the report is the reference by the Surveyor-General to the hot lake on Mt Ruapehu, to which much attention has been paid since the volcanic eruption. Mr McKerrow says ‘it has long been known that there was on the summit of Ruapehu a small lake of hot water girdled by everlasting snows, but hitherto little credence has been given to any assertion as to steam issuing from it. If it did occur it certainly has been for many years past a very rare event; however, during the months of April and May steam has frequently been seen to issue.’ Mr Cussen, one of the surveyors who lately ascended Ruapehu, states that in April last, he noticed for several days a column of steam rising high above the mountain top, and another Surveyor, Mr Wilson, says: When observing angles at Pipipi on the morning of the Ist May I noticed a column of steam about 300 feet high ascending from Ruapehu, and since then I have occasionally seen small quantities of steam issuing from it. A third Surveyor, Mr Dunnage, also mentioned having seen the hot lake on the summit and steam rising from it”.

Similar reports are presented in the Wanganui Chronicle (20 August 1886), Timaru Herald (21 August 1886), Poverty Bay Herald (23 August 1886).

The Wanganui Chronicle (26 April 1894) prints a letter from Mr GF Allen who discusses various aspects of survey measurements and activity, Mr Walter Dunnage, assistant surveyor, in his report for 1886 (the year of the Tarawera eruption), says, respecting his ascent on May 8 (evidently to the highest peak):

“The snow was in a favorable condition for climbing, but it was necessary to cut each footstep for the last 1000 ft, …Large quantities of steam were issuing from

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the little lake in the centre of the crater, nearly 1000 ft below us, but was all condensed before reaching the top of the crater…I was on the top one hour and ten minutes. There was no commotion of the water, or great variation in quantity of steam …On July 15th, Mr AD Wilson, District Surveyor, was at Pipipi, and saw a column of steam [about 300 ft high] rise straight into the air from Ruapehu. This lasted for some time. As the crater is deep, I think the water on this occasion must have been boiling fiercely … The steam on this occasion was seen by a good many people. I feel sure that Mr Dunnage has over estimated the depth down to the crater- lake, which Mr Cussen considers about 300 feet, but l am inclined to agree with Mr Dunnage that the water must (on July 15th 1886) ‘have been boiling fiercely’ I have copies of sketches of Ruapehu made at Cambeltown flagstaff, by Mr Samuel Henry Drew on July 21st. 1886, and at Newton-Lees by Mr John Morgan on August 19th, 1886, each of which shows a column of steam rising from the position of the crater. Mr Field about the same time saw steam columns rising thence on several occasions; and I and my survey party at Orangitetaia, near the junction of the Wangaehu and Manga-whero, saw two large puffs rise from the site of the crater on July 9th 1886 at 12. 02, and 12.12 noon. The mountain was free of clouds at the time, and we saw the steam both with the maiden eye and through the theodolite telescope …”.

The Wanganui Chronicle (29 July 1886) also reports:

“Mr Edward McDonnell, the manager of Karioi station, at the foot of Ruapehu, was in town yesterday, and not only confirms the fact of the mountain steaming, but states that, since the Tarawera outbreak, the Wangaehu River, which till then was quite milky and nauseous from the quantity of sulphur and alum in solution, has become quite clear and pure. This, coupled with the fact of the Waikato becoming turbid, indicates some internal change in Ruapehu, which has turned the sulphur and alum in another direction, the sources of the Wangaehu and Waikato, being only a short distance apart, high up on the mountain side”.

A letter to the Wanganui Herald (19 August 1886) reports a significant change in the water of the Wangaehu River:

“Sir, l see by the Wanganui paper of the 30th July, 1886, that Mr Edward McDonnell, who resides near the base of Ruapehu, says that the water of the Wangaehu River is, for the first time within the memory of the natives, quite sweet and clear. It is well known that the Wangaehu River takes its source from the east side of Ruapehu, the stream rushing out of that mountain, the waters of which have hitherto been of a grey whitish colour, somewhat like milk and water, and so strongly impregnated with sulphur and mineral deposits as to be most disagreeable to the taste and smell, the very stones over which it flowed on its way to the sea being coated with a yellowish slime, so that the water, even at the mouth, was unfit to drink …[and attributes this to the recent eruptive activity] …The late eruptions, there is little doubt, must have removed, or changed, the channel of the impurities which formerly flowed into this river, despite the opinions of Dr Hector and others to the contrary. No time should be lost in introducing the salmon and trout before the eels multiply, as they are the principal, if not the only enemies the young fish have”.

A further letter appears in the Wanganui Chronicle (23 August 1886) from Mr John Morgan:

“Sir, Much has been said and written lately concerning the activity of Ruapehu, but hitherto I have been rather skeptical on the point, and am at present

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somewhat in doubt about it. After this morning, however, I can not longer doubt that people may have seen what to them appeared to be smoke or steam, or both, issuing from Ruapehu. I live in a position where Ruapehu can be seen in all its grandeur in bright weather, and have on many occasions seen what appeared to be signs of activity there, However, this morning, from 6 till 9 o’clock, there was smoke or steam, or both, ascending to a great height from near the second peak from the north, also from the northern slope, at a point about one third of the way down the latter I have often seen lately. I still think that this does not arise from Ruapehu, but from Ngauruhoe or Tongariro; it this is so it must rise to a great height to be seen, as it was this morning, over the top of the mountain, those who may have been watching the action of the mountain must have seen that it appeared as though it were the action of some mighty geyser, as the column ascended at intervals of a few minutes in large puffy clouds. After 1 o’clock large masses of white fleecy clouds began to envelope Ruapehu from base to crown, bearing away in a north westerly direction, almost to Mt Egmont. At one time the clouds formed a very beautiful picture, and such as is very seldom seen, even in this land of the wonderful and grand. The morning was bright, and what I have attempted to describe was very marked and distinct. I must conclude that there is great volcanic activity going on somewhere in or near the vicinity of Ruapehu”.

The Star (29 September 1886) and several other papers report:

“The Herald’s Mata Mata correspondent telegraphs this afternoon that a vast column of steam can be seen rising today to a great height over Ruapehu. It appears as though the mountain were in active eruption”.

The Bay Of Plenty Times, (30 September 1886) reported:

“activity of Ruapehu Auckland, last night reports reached here yesterday that Ruapehu is in a state of eruption”.

While the Waikato Times (30 September 1886) quotes:

“A telegram from Taupo, referring to the report circulated in Auckland that Ruapehu was in eruption, says there is not the slightest sign of any action at Ruapehu. To-day was calm and clear and we had a good view of the mountain covered thickly with snow. Tongariro was steaming, but no more than usual. There were no earthquakes or alarming signs of any kind”.

Several others also carry these disclaimers, e.g., Bruce Herald (1 October 1886):

“A telegram from Auckland of Tuesday’s date stated that Ruapehu appeared to be in active eruption, but it subsequently turned out that the appearance was caused by a bank of clouds which was mistaken for steam. Ruapehu and Tongariro are thickly covered with snow”.

A summary story in the Otago Witness (1 May 1907), which attributes Dr P Marshall as it source reports:

“From time to time the volume of steam is so great that the water of the lake is thrown up into the air along with volcanic dust and mud, and for a time Ruapehu becomes an immense geyser. So far as records go, lively action was first noticed in 1887, but the most violent outburst that has been known to occur was in 1895, when the column of steam and mud was ejected to a height of at least 6000 ft

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above the top of the mountain. The photograph of the lake issued with this number was taken on December 30 last. The lake was not then perceptibly steaming, but it was not frozen over”.

The Ashburton Guardian, 22 June 1887 reports from Wanganui on June 22:

“A large cloud of steam is ascending from the top of Ruapehu and is visible from here. Today it is thought that the steam is rising from the hot lake known to exist in a crater in a hollow on Ruapehu”.

Cussen (1887) reported:

“deep down in a crateral hollow of basin-like shape, its steep sides covered with perpetual snow and ice, is a pool of water of a greyish-cream or drab colour. From the trig-station we overlooked this lake, the peak on which we stood being the south-west portion of the old crater-lips which surround the lake. From its peculiar surroundings of snow and ice, it was difficult to estimate with any degree of accuracy the diameter of the lake, and time would not allow of a proper measurement. It appeared to me to be nearly of a circular form, and 500 feet or more in diameter. It was quite impossible to descend to the lake, except by the aid of a long rope, and even then the descent would be attended with danger and difficulty. When I got on the top of the peak I noticed little clouds of steam rising from the surface of the water. On watching more closely, the water appeared now and again to assume a rotatory movement, eddies and whirlpools passing through it from the centre to the sides, and steam flashing up from those eddies, leaving little doubt in my mind that the water was in a boiling state. Close to the water the sides of the crater are bare of snow, and appear to be formed of loose particles of rock and volcanic ash; above are steep inclines of snow, sloping in all directions towards the water and terminating in icy masses overhanging the lake. The masses of ice show, in the cracks and crevasses which intersect them, and in their fringes of icicles, the effect which the heat from the lake has on them.

The waters of Wangaehu have a sulphurous taste and smell. Its course can be traced down the eastern side of the mountain from nearly the top of the cone in which is the hot lake; it may therefore be inferred that the water receives its character from this lake, through a subterranean passage in the mountain. Since discovering that the crater contained hot water, I have mentioned the fact to the oldest Natives in the district, and they all concur in the belief that it is something new. I am, however, inclined to doubt this, and to believe that a low volcanic heat must have prevailed there throughout. Five years ago, when engaged in triangulation on the Kaimanawa Ranges, I noticed hanging over Ruapehu, in the position of the crater, what seemed to be a cloud mass. This I remarked more than once, but I did not know of the existence of the lake at that time, and I considered that it must be a cloud or fog rising through some of the gorges of the mountain, although it closely resembled a column of steam. I may also mention that some eighteen years ago, (I am informed), an abnormal flood occurred in the Wangaehu River, carrying down with it large blocks of snow and ice. There had been no heavy rains at the time to account for this flood: it is therefore reasonable to infer that it was caused by an escape of the warm water from the lake, passing down through some underground passage below the edge of the water, and thawing the snow and ice on the mountain side. This, however, appears certain, that before or about the beginning of April, a considerable increase of volcanic heat in the Ruapehu crater took place, which continued to

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increase until towards the end of May, after which time I had no opportunity to observe it.

On the 16th of April I noticed a well-defined column of steam rising from the crater, several hundred feet above the mountain top; it was also visible several days subsequently. I showed it to several of the Natives, who said they never, had known of such a thing before. If it were of common recurrence, and in such volume, I think it impossible that it could have escaped the notice of the Natives.

On the 23rd May, the weather being very clear and bright, a larger column than usual ascended from the crater, about 300 feet above the mountain, spreading out horizontally into a cloud-like mass, the outside portions of which descended again and rolled down the mountain side. Towards noon this column began gradually to decrease, until it disappeared altogether by sunset. Since the end of May the dull weather prevented any further observations of the mountain”.

Wanganui Herald (2 July 1887) comments:

“About the same time that steam was seen rising from Ruapehu, there was a strong smell of sulphur in Tauranga, White Island being the source”.

It was during September 1887 that Tukino Te Heuheu IV, paramount chief of Ngati Tuwharetoa, gifted the summits of Tongariro, Ngauruhoe and Ruapehu to the crown, for protection and safe keeping.

Hill (1895) while discussing the changes which took place at Te Mari, situated at the north end of Tongariro, in November 1892, comments they correspond exactly with those which took place on Ruapehu in May 1887, and again in March of 1895.

The Nelson Evening Mail, (22 October 1887) comments:

“We have to acknowledge the receipt of the Illustrated Australian News of the 15th inst. It is an exceptionally interesting number, both as regards the illustrations and letter press. The former include some capital sketches in Samoa in connection with the late disturbances there, a spirited view of Ruapehu volcano in an active state so far as emitting dense volumes of smoke is concerned” (Figure 5.1).

The date of the activity is not clear.

This is reported in the Inangahua Times (3 June 1889):

“Two gentlemen who left here for Ruanui (Mr Studholme’s run) and returned on the Ist inst., state that it was reported to them that a startling phenomenon had occurred in the Wangaehu River, which is of a milky colour, very strongly impregnated with sulphur, and quite shallow. This river, which takes its source from the eastern side of Ruapehu, and empties itself between Wanganui and Turakina, usually so quiet, suddenly burst forth on the 22nd April from the mountain, and in 10 minutes time became a swollen, raging torrent, bank high, and of inky blackness. There has been no such outbreak previously in the memory of Natives or Europeans who live near its locality, and it is a source of wonder and amazement to them. Possibly the cessation of steam from the hot lake on the top of Ruapehu, reported a short time since, may have had something to do with it — Mr JE Grace, who happened to be mustering sheep on

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the Kaimanawa range (which is opposite to Ruapehu) on the above date, states that he saw an immense column of steam ascending high in the air, which lasted for about half an hour, and then disappeared. He thought it at the time most extraordinary, as he had lived in the district a great many years, and never saw such a sight before”.

This is also reported in the Wanganui Herald (25 May 1889).

The Hawke’s Bay Herald (1 May 1889) reports:

“Yesterday, at twenty minutes past 12 o’clock, a large body of steam rose suddenly in a huge column from Ruapehu, the mountain showing every sign of being in a state of activity. The outburst was seen by the Governor and his party, Lord Onslow being the first to direct attention to the phenomenon. Mr S Crowther, who was driving the coach containing Lord and Lady Onslow, had been looking at the mountain shortly before and there were then no signs of steam, so that the subsequent explosion was quite sudden”.

The following account is reproduced in several papers; the Marlborough Express (2 May 1889), Evening Post (2 May 1889), Poverty Bay Herald (2 May 1889) report:

“a Strange Phenomenon. Wanganui, May 2 The Karioi correspondent of the Herald writes, under date April 29 this afternoon, about 2.30, the Wangaehu River rose from three to four feet in less than half an hour, and is still rising, the water changing its color from milky hue to a dirty black. As we have had no rains, and the river, up to-day, being lower than I can remember ‘for years past, the only solution to my mind is that some volcanic eruption has taken place on the Ruapehu; though, strange to say, no one here heard any particular noise”.

This is followed up in the Wanganui Herald (3 May 1889):

“The following allusion in Wednesday’s Hawkes’ Bay Herald to Ruapehu’s activity on Tuesday last may afford a key to the rise in the Wangaehu River referred to by our Karioi correspondent: Yesterday, at twenty minutes past 12 o’clock, a large body of steam rose suddenly in a huge column from Ruapehu … continuing the story from the Hawkes Bay Herald. The Poverty Bay Herald (3 May 1889) also reports At Taupo on Monday a grand and magnificent sight was witnessed at eleven o’clock, and again about noon, when Mount Ruapehu suddenly sent up a column of steam to an enormous height. Some thermal action was apparently going on in the hot lake on its summit, the outburst being in the nature of an enormous geyser ascending rapidly and then subsiding in a few minutes. A Napier paper writes on Wednesday: Yesterday, at twenty minutes past 12 o’clock, a large body of steam rose suddenly in a huge column from Ruapehu the mountain showing every sign of being in a state of activity. The outburst was seen by the Governor and his party, Lord Onslow being the first to direct attention to the phenomenon. The explosion was quite sudden. Possibly Ruapehu wished to show the visitors what one phase of colonial blowing was like”.

Hill (1891) reports on the 1st May 1889:

“The residents in the vicinity of Taupo Lake witnessed, about 11 o’clock, and again at noon, the spectacle of a grand and magnificent explosion of steam on Mount Ruapehu. So runs a telegram from Tapuaeharuru of that date; and it appears that the Whangaehu was in high flood, and rose 3ft. or 4ft. in the short space of a few minutes. At the date of my visit there

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was ample evidence to show that a great geyser-like explosion had taken place, for quantities of blue mud and many large boulders were to be met with along the east and north-east portions of the snowfield in the vicinity of the lake, and a kind of wave-margin of coloured snow and blue mud could be traced on the ice between the south and west peaks, and which had evidently been deposited by an explosion of some kind. The wave-rim could be traced over the entire ice field sloping towards the lake, and the bluish-grey material upon it resembled what was thrown out at Rotomahana during the time of the Tarawera eruption, and bore no likeness to any of the surface-rocks on the mountain”.

The Hawke’s Bay Herald (7 May 1889) reports this summary:

“A correspondent at Karioi, and another at Moawhanga, kindly send us accounts of the eruption of Ruapehu last Monday, which, however, do little more than confirm the reports already published. In the morning Mr Alexander Munro, shepherd on Mr Studholme’s Karioi station, observed a vast column of jet black smoke issuing from the crater of Ruapehu. It disappeared towards night, when Tongariro ‘began to steam up at an awful rate.’ One correspondent suggests that the sudden rise of several feet in the Wangaehu river was due to the melting of the snow on the mountain caused by the heat evolved by the volcanic action, The other observer, however, mentions that two streams have their source within half a mile of each other on the slopes of Ruapehu, and flow parallel to each other, divided only by a spur, for some ten or twelve miles, when they form the Wangaehu river. One of these streams is strongly impregnated with sulphur, while the other is quite fresh, only the sulphur stream rose suddenly, the other not being affected at all. If melting snow had caused a, rise in the river, both contributing streams must have been equally affected. It is therefore suggested that the mountain must have ejected an immense quantity of sulphurous water at the point where the sulphur stream has its rise. The flooded stream was of a muddy color, and evidently carried a good deal of some kind of deposit. Two bottles of it were secured by Mr Batley, to be sent to Sir James Hector. It is worthy of note that, though this is the third recorded eruption of Ruapehu, until now very few people have believed in it as an active volcano, and have ascribed previous reports to the deceptive appearance of clouds resting on the summit. The first time was in 1869, when Mr RT Batley distinctly saw the mountain throwing out immense clouds of steam, and the second was in 1886”.

A similar story is carried in the Taranaki Herald (11 May 1889).

The Feilding Star (4 May 1889) reports:

“Out of compliment to our new Governor, Mount Ruapehu got up steam when his Excellency was passing, and gave him a welcome salute … the rising of the Wangaehu River which appeared in our last issue, the Hawkes Bay Herald says that at 20 minutes past 12 on Tuesday a large body of steam rose in a column from Ruapehu”.

The Wanganui Herald (1 June 1889) reports:

“This morning the geysers on Ruapehu were very active. From daylight until about 8 o clock the columns of steam could be seen ascending at regular intervals, and so rapid were they that before the steam cloud of one had cleared off another arose to perform the same evolution. It is now some two or three years since I last saw such activity on Ruapehu, and since then much has been

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said on the subject, and I believe some are still doubtful as to the activity of our grand old mountain, however, I feel sure that this morning’s appearance was sufficient to convince the most skeptical”.

In June 1889 the Bush Advocate (6 June 1889) reports:

“Between 6 o’clock and 7 o’clock on Saturday [1 June] morning there was another outburst of steam from Ruapehu, afterwards followed by dense smoke. This is said to be the first time smoke has been observed to rise from Ruapehu. Shortly after the outburst the river Wangaehu, which flows from the mountain, and which rose several feet when the outburst a few weeks ago took place, almost suddenly became dry, and its beds is now dry”.

The Evening Post (12 May 1936) reports:

“In August 1889, it [Ruapehu] was active and ejected its waters, the result being a sudden flood in the Wangaehu River: and mud and boulders of blue clay scattered over the ice and snow”.

The Wanganui Chronicle (6 December 1889) reports a flood in the upper Wangaehu River:

“On Monday, about 9.30 am a loud report was heard both at Mangamahu and at a place some seven miles further up the Wangaehu, which is supposed to have originated at Ruapehu. A similar report was heard yesterday at 3.20 a.m. at both places the Maori … attributing this sound also to Ruapehu. The Wangaehu yesterday morning was of the colour of raw sienna, having risen about six inches during the night. The discoloration yesterday at noon was strongly marked down to near the junction with the Mangawhero, below which the Wangaehu was of its normal colours”.

It’s not clear if this observation is due volcanic activity or weather.

A1.6 1890S

The Wanganui Herald (21 March 1890) reports:

“Napier, March 20. A party, including Mr Hill, Inspector of Schools, a representative of the Hawke’s Bay Herald, and several local residents, recently ascended Ruapehu and Ngauruhoe. They had a magnificent view of the crater of the former, and were able to make a closer inspection of it than any previous explorers. They found the lake in the crater to be boiling furiously — a point which has hitherto been in dispute. It is believed that it has boiled only since the Tarawera eruption”.

This story was also covered in the Southland Times (21 March 1890), Poverty Bay Herald (21 March 1890), and the North Otago Times (22 March 1890).

The Hawke’s Bay Herald (27 March 1890) carries a long account of the ascent repeated here for completeness of the descriptions:

“The party struck down the crater as far as it was safe to go (Figure A 1.1 and Figure A 1.2). Mr Hill had taken a tin bottle with him and a large roll of twine, to get some of the water of the lake and set for ever at rest the question of whether it was boiling. He lost his bottle and string in the attempt, but he was convinced

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that in disputing the existence of an active crater he had disputed a very concrete fact. The sun was then shining brilliantly, and beyond doubt the party got a better sight of the crater than any previous observers. For the lake was bubbling and boiling furiously - now sinking down, and again rising until it touched the glaciers which hung, huge walls of solid ice, on the west and south sides of the crater. On the other two sides were cinders and boulders. There were banks of smoldering ashes, and an alpine stock thrust into them came up hot. At the junction of the glacier and the cinder banks there was a waterfall which thundered down into the crater. Time and again, too, a huge mass of ice would detach itself and fall with deafening noise into the boiling lake. There were also unmistakable evidences of very recent greater activity. It will be remembered that when the Earl of Onslow was making an overland journey it was said that his party saw volumes of steam arising from Ruapehu —an announcement discredited by the scientists. But there, on the top of the glaciers, were blue clay and huge boulders, which must have been very recently left there, and marks on the ice indicated that the lake must have risen to nearly the lip of the crater, leaving these mementoes of its attempt to ‘break bounds’”.

Figure A 1.1 Map illustrating the summit of Ruapehu (Hill, 1891).

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Figure A 1.2 Sketch of the Crater Lake area provide in Hill (1891). Note the landslide scar on the inner flank of the peak on the left (Pyramid).

The second installment is reported in the Hawke’s Bay Herald (4 April 1890) describing an ascent to the Wangaehu Valley and includes these comments:

“We had brought candles with us, and lighting them, we pressed forward to explore the deep cavern beyond, but to do so had to climb over sharp, slippery rocks, which were covered with a coating of ice, as if they had been glazed with glass, while the white waters streaming beneath us fell into a deep eddying pool. We managed, after some difficulty, to cross the stream in the second cave, and to penetrate a considerable distance along the treacherous rocks into the very centre, as it were, of the great mountain : but just as we were winding a kind of subterranean passage, which looked like a short cut into eternity, our lights went out, owing to the water falling from above, and as we could hear nothing but rushing water ahead, we, with some difficulty, beat a retreat into the first cave, which looked like a fairy palace in comparison with the dark cavern we had just left. These caves were at an altitude of 7000 feet above the level of the sea, and we were now at the true source of this remarkable river …There is some evidence of a connection between the lake and the river in the fact that when, about a year ago, the summit crater was observed to be throwing up clouds of steam, the Wangaehu River rose several feet in a few minutes, and the water was more charged with minerals and mud than usually. As against this theory, however, may be set the ascertained facts, that while the lake on the summit is boiling, the water of the Wangaehu at its source is quite cold”.

Thompson (1926) records Hill’s observations of March 1890, following his climb, and goes on to report a geyser like eruption on 1 May. This most likely refers to the 1889 activity.

A further ascent is reported in the Wanganui Chronicle (23 January 1891) and reports:

“A party from Hawke’s Bay ascended to the summit of Ruapehu on Tuesday, and found dense black smoke issuing from the crater. On their return they were

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overtaken by a very heavy fog, and they had a rough experience. Mr Wood (head master of the Boys’ High School, Napier) and his son, Mr Olson, and Mr Westall, were all stricken with snow-blindness, and had great difficulty in descending”.

The Evening Post (5 February 1892) reports:

“Auckland 4th February. Increased thermal activity in the Lake Taupo district is reported by a correspondent of the Herald. He states that an immense volume of steam is issuing from Ruapehu”.

The Hawke’s Bay Herald (24 May 1892) carries a letter from Mr HC Fields on the first ascents of the mountain and the observation of a lake. Observations include:

“The existence of the lake has long been known here, and perhaps the following may interest to your readers. I first heard of the lake in 1874 or 1875, from Mr A Murray, of Marton, who had ascended the mountain in company with Dr. Carl a short time previously. From its appearance Mr Murray judged that at a certain level its water percolated through the mountain, and formed the source of the sulphur and alum stream of the Wangaehu. A similar stream, on the western side of the mountain, is also probably supplied from it. ….. About 1878 Mrs Birch visited it in company with her husband and two or three other gentlemen. By one of these last, or from information given by him, the model of the mountain in the Wellington museum (which shows the lake) was constructed. The reason why the lake is not mentioned by Mr Kerry Nicholls, who ascended the mountain in 1880, was simply that that gentleman only reached the northern peak, from which it is apparently not visible … During the last four or five years several parties from here have climbed the mountain, and one of the last persons who did so, in January of this year, took some photographs from the summit of the mountain, one of which shows the lake. Large copies of these photos have been exhibited in the window of our local photographer, Mr Martin, since February …I do not think the lake was known to be hot till Mr Cussen, a Government surveyor, observed it boiling soon after the Tarawera eruption, and for some time afterwards the column of steam from it was often seen from Wanganui, and still is occasionally. At that time the sulphur stream of the Wangaehu ceased to flow for some time. This latter phenomenon had also occurred at the end of 1880, at which time the north-east peak of the mountain was emitting a great quantity of steam, as if hot all through; so that no doubt the lake was boiling then, though no one actually observed it”.

Hill (1895) reports:

“Mr Walter H. Dunnage, of the Survey Department, with two of his men. Mr Dunnage has made the ascent of the mountain on several former occasions, and when visited by him at Easter last year (1894) the lake was of a beautiful green colour, apparently cold, with a sulphurous deposit on the surface here and there. This had all changed on the 5th of April of the present year, when the lake was of a milky colour, with steam rising from its surface, and surrounded on all sides but the east by a beach from half a chain to a chain in width. The lake was 10ft. or 12ft. lower than he had seen it before (Figure 5.2), and, what was the most fortunate thing of all, the party of three were able, with due precaution, to reach the margin of the lake—the first human beings who had ever done so. The temperature of the lake was found to be 128°F. The margin of the water was covered with blocks of very friable scoria, among which were innumerable small

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boiling springs causing a dull, weird sound. This visit was made about a month after the explosion which took place on the 10th of March, when a column of steam was thrown up at least 1,000ft. Above the crater; and the same thing was observed on several succeeding days”.

A fuller account by Dunnage is found in Lands and Survey (1895: pg. 171-173).

A photograph of a sketch attributed to Allen in 1894 is found in the DSIR photograph collection and reproduced as Figure A 1.3. The source publication is not identified.

Figure A 1.3 G Allen’s 9 March 1894 sketch of the Crater Lake area.

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In a review article by Mr Malcom Ross in the Otago Witness, 5 June 1907 it was reported that: “Jack Chase, a half-caste Maori, who was piloting two titled Englishmen through the district in 1869, always maintained that they saw a big eruption from Ruapehu. All doubts on the point as to whether the mountain was capable of violent eruption were, however, set at rest when, on the 10th of March, 1895, the great monarch of the North Island ‘threw up a column of steam at least a thousand feet above the crater. There was a splendid display of thermal activity for, several days, the volume of steam gradually diminishing until it no longer rose above the crater’”.

The Evening Post (11 March 1895) reports eruptions from Ruapehu and changes in the Wanganui River:

“This morning there was a tremendous ejection of steam from Ruapehu, the lake on the summit of the mountain having evidently been converted from cold water into a great solfatara. Since midday the mountain has been ejecting smoke and ashes … Water in the Wanganui River is very much discoloured this morning….. Other telegrams state that the Wangaehu, which takes its rise in Ruapehu, and is always charged with sulphur, is very muddy and discoloured”.

Similar reports appear in the Colonist (11 March 1895), Hawke’s Bay Herald (11 March 1895), Feilding Star (11 March 1895), Taranaki Herald (11 March 1895), Nelson Evening Mail (11 March 1895) and other papers. The activity is illustrated in a sketch by George Allen (Figure A 1.4)

Figure A 1.4 George Frederic Allen sketched this view of Mt. Ruapehu on 10 March 1895, the day it erupted. The scene was that looking north from his home on ‘Mr Allen’s Run’, Te Pohue, seven miles from Mangamahu. Notes made in the margins marking locations are as follows: Para-te-tai- tonga, Mauhangatahi, Valley of the Wangaehu, Ruapehu = 9175 ft., 34 miles dist., Steam jet from Te Mari, about 44 miles dist. Source: http://webspace.webring.com/people/ sh/hanson_allen/).

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Activity continued as reported in the Wanganui Herald (13 March 1895):

“Wellington, March 13. A telegram to the Times says Mr Peters at Waioru, reports that after a good stiff gale on Sunday last immense volumes of smoke and steam burst out from the crater of Ruapehu with terrible force, followed by a heavy earthquake and the Bay Of Plenty Times (13 March 1895) reports Tuesday; Ruapehu commenced action about 6 o’clock on Sunday morning and increased in activity toward afternoon when the steam cloud was over 5,000 feet high, there is probably a grand geyser eruption from the old crater. Peters, the well known coach proprietor reports a great discharge of water, the Wangaehu River is flooded and the Wanganui River very greatly discoloured”.

The Feilding Star (12 March 1895) carries this short comment:

No activity is known for the 1830s. While on 13 March 1895 the Wanganui Herald reports the activity and the Waitotara correspondent comments:

“The only previous occasion upon which I have seen steam from Ruapehu, was on the 8th of May 1887, when I enjoyed a much closer view. At that time the quantity of steam was considerably loss and arose less rapidly than was the case on Sunday”.

The Wanganui Chronicle (14 March 1895) reprints a letter from JM:

“I have now to record an eruption that took place yesterday afternoon. Sunday, 10th March, was a remarkably fine bright sunny day, with scarcely a puff of wind blowing or a cloud in the sky. Ruapehu stood in all its snow clad grandeur as usual on such occasions. I had been viewing its beauty many times during the day. In the afternoon, about half-past four, I was gratified by a sight such as I had scarcely seen before, though a resident of 40 years in the district. Apparently from the central cone there arose a large volume of smoke or steam, or smoke and steam combined. Its ascent was beautifully grand, at times gorgeous. When at a great height (I imagine some thousands of feet) it gradually disappeared, but the dense supply was kept up for hours. It was truly magnificent especially towards sundown, when the mass was gilded by the rays of the setting sun. It then was a sight worth seeing. I have no doubt but that which I have attempted to describe was witnessed by hundreds, and there maybe some that will be able to do more justice to the subject than I can; at any rate I hope so. No doubt the occurrence of Sunday afternoon will convince the doubting ones as to the activity of Ruapehu. May we not congratulate ourselves that we have such a safety valve for these districts?”.

Also published in the Feilding Star (16 March 1895).

A further story by the Wanganui Herald (16 March 1895) adds this detail:

“Today, [March 10th] about 12.30 pm, was witnessed a most wonderful as well as appalling scene on the summit of Ruapehu. Dense volumes of steam, smoke and showers of dust were visible to the naked eye of those who were fortunate in

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being in the vicinity of Karioi. Every now and then the volumes rose to a tremendous height, again subsiding and emitting masses of black sulphurous smoke, which can be seen floating away for miles northward. We anticipate that the country will be covered in that direction with a coating of whitish dust … Mr E McDonnell, of Karioi station, whilst passing the Wangaehu River, noticed that it was discolored and swollen and has continued so, evidently showing that the outbreak commenced some days ago, and the water in the crater has been gradually forced out, so causing the river to flood and filling it with debris, etc. The smell of sulphur in the river is intense”.

The Star (19 March 1895) and Feilding Star (19 March 1895) report:

“A party who ascended Ruapehu from Karioi reports that the lake in the crater has been blown out, and that boiling lava has taken its place. The mountain is shaking”.

While the Taranaki Herald (22 March 1895) reports this account:

“On March 14th, Mount Ruapehu was visited by a party including himself D Sutherland, head shepherd, Chase contractor for carting the wool, a lad named Craig and others. Young Craig went up the mountain, as near the top as he could. At that time it was belching forth gigantic rocks in the direction of Tokaanu. Steam was coming from the crater, which at the mouth is estimated to be ten chains long by five wide, and the mud was noticed to be very thick and gradually approaching to the lip of the crater. The sulphur streams running through the mud give the latter a most peculiar appearance, tingling it with rainbow colours. The supposition is that the steam will gradually burst up the mud, and fears are therefore entertained that before very long there will be a big upheaval”.

Hill (1895) states that the changes which took place at Te Maari in November 1892, correspond exactly with those which have taken place on Ruapehu in May, 1887 and again in March 1895.

Mr Lowe, Government Surveyor, saw the lake boiling during his ascent in 1895. Great explosions were taking place, and steam was also issuing from holes in the old ice-filled crater near the lake (Otago Witness, 5.6.1907).

The Star (21 March 1895) reports that:

“The reported activity of Mount Ruapehu, in the centre of the North Island, is significant, not on account of the violence of the outburst, but because of the fact that for sixty years, this snow-clad mountain had given no sign of volcanic energy, beyond the existence of a warm lake half-way between the surrounding plain and its summit. About sixty years ago, according to the recollection of aged Maoris, ‘Ruapehu was an active volcano, entitling ashes, fire and smoke; but the action was feeble, and from that time until a week ago the mountain was quiescent, though the neighbouring hill, Tongariro, was always more or less active’”.

The 1830s are indicated as a time of past activity by this account.

An ascent is reported by the Wanganui Herald (22 March 1895):

“I and a friend wishing to see whether this was the case visited the top of Ruapehu, which I believe is the highest point in the North Island of New Zealand.

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Unluckily we did not get a perfect day, as far down below us the north-west wind was blowing clouds across most of the country within our vision …The crater of the mountain itself has a beautiful snow field all round it with the exception of one side, the source of the Wangaehu River, which drains the lake in the crater. All we could see that showed signs of volcanic action was the lava that ran out hundreds of years ago. The steam coming from the crater and a discoloration of the snow field on the side where the wind was blowing, the smoke or steam that came out on the first two days. We were not round on that side, but it looks like fine ashes or dust from smoke. The lake that was originally in the crater we could not see, it is either very much lower or gone altogether, and it is just pure steam that is rising from it now. This steam is not coming in puffs, but in a steady cloud, as if there was a large body of water boiling below. The steam does not seem to have much affected on the large snow field many acres in extent which surrounds the crater with a gentle slope towards it”.

A further witness account is reported by the Hawke’s Bay Herald (22 March 1895):

“Ruapehu in eruption. Sir, ln reference to the leading article in your issue of the 12th instant re the activity of Ruapehu, I would corroborate the statements of the Taupo postmaster. I myself with several friends were at Ruanui, which is situated about 15 miles as the crow flies to the south-east of the mountain. We all saw dense volumes of black smoke emitted from the peak (as it appeared to us) on the Pipiriki side of the mountain, the wind was blowing from the south-west at the time we were not in a position to see whether ashes were thrown out with the smoke, which the Taupo postmaster would be able to discern, …Having been in this district on an off for the last twelve years I have frequently seen the steam rising from the hot lake on the top of Ruapehu, but never before witnessed the scene that I and my friends saw last Sunday, the 10th instant. —LCH Macwhirter, Hautapu, Moawhanga, March 16, 1895”.

The Wanganui Chronicle (25 March 1895) reports changes in the Wangaehu River:

“The Wangaehu, which, as before mentioned, rose suddenly three or four feet on Sunday, the 10th, between 11 am and 8 pm, fell to its usual level about Wednesday, and has since then been entirely free from mineral taste or smell, being perfectly free and drinkable, though a little discoloured. It is now unusually low, and indeed some of the old residents say lower than they have ever seen it. Possibly the eruption has thrown out the contents of the crater lake, thus causing the sudden flood on Sunday, the 10th and has thus stopped the source of supply of the alum spring and the spring charged with sulphates of iron and alumina at the head waters of the Wangaehu. Should it fall much lower it may indicate that there is a dam formed somewhere near the head of the river, possibly by ice and snow slips thrown down by the eruption, which might lead to a flood similar to that which in (or about) 1862 [1861] carrying away the Wangaehu Bridge” and a further summary on 3 April states:

“Presently it was evident that the giant was fairly awake, and from his lofty summit there rose in slow and majestic grandeur a magnificent cloud. Soon it reached a thousand feet in height, then higher and higher it rose in calm dear air in one unbroken column for upwards of 6000 feet …the centre of the shaft became darker and denser, and it was evident that a geyser eruption upon a scale of unparalleled magnificence …about an hour later the drift of a shower

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was distinctly seen falling from the overarching cloud …the contents of the lake were discharged at this latest eruption in rapid streams pouring down the mountain side and flooding the Wangaehu River and discolouring the waters of the Wanganui, after all the water had been discharged the steam escaped with a thundering roar, and a large quantity of volcanic dust was expelled and distributed over the country in fine showers …”.

A further summary is published by the Wanganui Chronicle (3 April 1895):

“On Sunday morning, March 10, the snow-capped giant Ruapehu was seen from the splendid vantage ground afforded by Ross’s Terrace Hotel, Taupo, …Presently it was evident that the giant was fairly awake, and from his lofty summit there rose in slow and majestic grandeur a magnificent cloud. Soon it reached a thousand feet in height, then higher and higher it rose in calm clear air in one unbroken column for upwards of 6000 feet. Seen from this distance, the shaft seemed composed of ascending rolling clouds which kept moving steadily upwards, and apparently dissolving into the cooler upper air. Then the centre of the shaft became darker and denser, and it was evident that a geyser eruption upon a scale of unparalleled magnificence was proceeding. A few hours later, and the lofty column was headed by a spreading cloud which opened on either side in midair, fully six thousand feet above the mountain top…Nearer to the mountain deep rumblings were heard on Saturday night and Sunday morning, and during the day a terrible roar, with a continuous earth tremor, accompanied the discharge. On the summit of the mountain, between the north and south peaks, was a vast crater lake fully a quarter of mile in diameter, which has been noticed to vary very considerably in temperature. Mr Park, FGS reported it frozen in 1886; and Mr H Hill, BA., as boiling in 1890, with evidence then of recent geyser action. Mr Ross also states that about that time he witnessed an eruption from the crater of successive puffs of steam, which sometimes reached a higher altitude than the cloud of Sunday last. There is also evidence of former outflows from the Crater Lake, but nothing of such unprecedented violence or importance could have been anticipated. The contents of the lake were discharged at this latest eruption in rapid streams pouring down the mountainside and flooding the Wangaehu River and discolouring the waters of the Wanganui. After all the water had been discharged the steam escaped with a thundering roar, and a large quantity of volcanic dust was expelled and distributed over the country in fine showers. On Monday lofty columns of steam occasionally ascended, but not to the same height as on the previous day, and only occasional puffs of steam have since been seen to rise from the crater. While the eruption was in progress a thin thread of vapour ascended from the cone of Ngauruhoe, and curling cloud could be seen on Tongariro, which indicated activity at Te Mari and Ketetahi…”.

In 1895 H Hill is reported in the Hawke’s Bay Herald (2 November 1895) quoting from the Alpine Journal describing the Crater Lake activity:

“the water in the lake at the time of my visit was in an intense state of commotion, and was a dirty, greyish blue colour. Wavelets, like soapy films, could be observed to pass in quick succession from west to east, and at regular intervals, at the moment of greatest activity, a cloud of steam would be suddenly thrown from the surface of the lake. This was followed by a subsidence and a brief period of quiescence. Immense cavities appeared at this time on the western side, underneath the ice wall, and there could be seen at the moment a yellow

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deposit like sulphur, but I was unable to ascertain with any degree of certainty the nature of the deposit, as the subsidence was very brief, for soon the motion of the water began again, and the same changes were gone through as described above. The duration of each pulsation and explosion would be at intervals of a little more than two minutes. A short time previous to my third visit an eruption had been reported as having taken place in the mountain, and my purpose was to ascertain if there was any evidence of such. The evidence was undoubted. Along the ice field small scoria stones were pilled up for 300 yards or more before reaching the lake, but the rim of the crater on the western side provided positive proof. For some 15 or 20 yards over the ice, extending from the rim of the crater in the direction of the peaks, there is a wave-like deposit of blueish grey clay, and angular blocks which bore no resemblance whatever to any rocks exposed on the mountain. These had evidently been deposited by a geyser like movement of the lake, which had reached above the top of the crater and deposited the material … I remained on the edge of the crater alone for a long time (my companion having gone to various places on the mountain), watching every movement and noting everything in connection with the unique crater lake. As to its activity there can be no reasonable doubt, and the recent eruption on March 10th last, confirm the opinion expressed by me in Vol XXXIV., pages 621- 22, of the Transactions of the New Zealand Institute, to the effect that the activity of the present crater is of long duration”.

“The Crater Lake lies due east of Ruapehu Peak … at 650 yards long by 500 yards wide, and from the lip to the surface of the water its distance is not less than 300 foot, or perhaps a little more. Surrounding the whole of the western half of the crater, with a single exception, is a perpendicular wall of ice, which goes directly to the surface of the water, whilst the eastern half is made up of ash bands of various colours, and from which steam is seen to be issuing, just as one sees within the crater of Ngauruhoe. At the point of junction of the ice and ash bands, on the south, is a waterfall of fairly large size, and the only sound to be heard in the vicinity of the crater comes from the falling water, except that now and then a crashing of falling ice is heard in the direction of the western peak”.

The Evening Post (12 May 1936) reported:

“about noon on Sunday 10 March 1895 an eruption producing an eruption column to over 6000ft, ejecting the lake and flooding the Whangaehu valley. Also the Mangtoetoenui and Manga-nui-a-te-Ao had mud and sludge in them. The upper Whangaehu River stopped after this event and the waters became useable as a stock water supply”.

The story of the first women to climb all three volcanoes is reported in the Poverty Bay Herald (18 March 1898), and Crater Lake is reported:

A letter to the editor of the Herald is recounted in an unknown newspaper and reflects on an eruption seen in 1898 and several outbursts between 1895 and 1898.

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A summary story in the Otago Witness (1 May 1907), which attributes Dr P Marshall as it source reports:

“From time to time the volume of steam is so great that the water of the lake is thrown up into the air along with volcanic dust and mud, and for a time Ruapehu becomes an immense geyser …the most violent outburst that has been known to occur was in 1895, when the column of steam and mud was ejected to a height of at least 6000 ft above the top of the mountain”.

A summary of activity in 1907 in the Bush Advocate (29 April 1907) reports:

“a great geyser action in this crater in April, 1895. Vast quantities of mud and water were ejected, the action being similar to that of the Waimangu geyser, but on an even grander scale …. “.

The Illustrated Australian News (1 April 1895) carries an illustration of Ruapehu in eruption (Figure A 1.5).

Figure A 1.5 An illustration of Ruapehu in eruption, printed in the Illustrated Australian News (1 April 1895).

In a review article by Mr Malcom Ross in the Otago Witness (5 June 1907) it’s reported:

“Mr Walter H Dunnage, in the survey report of 1895, states: — The reports published in some papers that fire and smoke rose from Ruapehu, and that large

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rocks, together with mud, had been thrown from the crater, I knew to be false before my ascent; but I thought, possibly, the lake had gone and that some mud had been ejected. However, this was not so, and the discoloration of the snow on the mountain side was due to the fine summer and autumn having melted the snow to a lower depth than usual, in many places nearly to the ground, leaving only dirty snow, which had misled many who saw it from afar”.

He continues to report from Dunnage:

“The four hours which we spent on the top of the mountain during a previous visit passed all too quickly. The finest view was from a point above the Crater Lake. In the midst of a vast ancient snow filled crater — like a beryl in a setting of silver — lay this little oval lake. Round the rim of its greeny blue waters ran an edge of brilliant yellow, and ever and anon, as if in answer to some ghostly incantation from below, trails of yellow sulphur floated out upon the waters, forming and reforming into weird figures. The lava rocks of red and black and purple that frowned above the steep ice-cliffs of the lake gave a note of contrast and served to emphasise the delicate beauty of the ice rimmed lakelet”.

Field (1896) reports after the eruption of Ruapehu, in March 1895, the sulphur stream which formed the highest source of the Whangaehu River ceased to flow, and the water had apparently, till within the last few days, been always sweet and pure. He reports:

“on the 15th instant large numbers of kahanaenae (New Zealand loach) floated dead in this stream, and others were dying and gasping for breath. The water had also again become turbid and sulphurous. The floating of dead fish continued for several days, and the water was still milky-looking, and smelt of sulphur. No doubt the fish floating down the Wangaehu were thus on their way to the salt water when they were killed by the sulphurous water, and the recent volcanic activity inland had reopened the sulphur spring”.

A story about Te Maari activity in the Star (6 January 1897) comments:

“Other parts of Tongariro are in their normal state, as also is Ruapehu. Ngauruhoe was emitting a good deal of steam yesterday evening, after comparative quietude for some days”.

The Poverty Bay Herald (19 August 1897) reports a very busy time:

“A Taupo telegram last week stated: The mountains have been unusually active for several days, nearly every known volcanic vent showing itself. Ruapehu is emitting a dark smoke, which is a great contrast to its snow covering, as also to the lighter nature of Ngauruhoe’s steam. Te Maari has exhibited its double column, and Ketetahi its single white above the latter. It is very apparent that the red crater on the summit of Tongariro is joining in the display. On Thursday afternoon Ngauruhoe sent up a vast column of steam to an estimated height of fully a thousand feet, which eventually took a downward course obstructing the view of the upper portion of the mountains”.

Friedlander (1898) reports on his ascent on the 4th April 1897, from the saddle between Ngauruhoe and Ruapehu. He reports:

“the crater of Ruapehu, at first sight, does not look like a crater at all. Closer and reflecting inspection, however, shows that the inner slopes of all the rocky peaks

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surrounding the snow-covered plain are much steeper than it’s outer. This and a smell of sulphuratted hydrogen, that every now and then was brought over by the cold southerly wind, reminded us of the volcanic nature of the mountain. I believe, has not yet been pointed out by previous visitors to the top—viz., that the famous lake (which, by-the-by, was steaming slightly and was apparently tepid) is situated not in the main crater (or, if there be two, in the southern of the two craters which cover Ruapehu’s top), but in a secondary cinder-cone”.

The Poverty Bay Herald (30 September 1897) reports an ascent of Ruapehu:

“As we ascended, the smell of sulphur became noticeable, and when we reached the plateau was very strong indeed. This plateau on top of Ruapehu, about a mile wide, contained a lot of vertical holes, as if gigantic earthworms had been at work … Having ascended this mound, we looked right down into the crater lake, which was all boiling up, and of a yellowy-blue colour, somewhat similar to a sulphur flame. The dark coloured steam crept round and round the edge with a loud, hissing sound, and, suddenly rushing into the centre, rose in vast columns, and completely hid our view to the eastward…The fluid was only about 25ft below the eastern margin of the crater, and must have recently overflowed, as the Wangaehu Glacier was all covered yellow. As the old trig …and while erecting a station there, a loud explosion took place in the crater, and the mountain trembled. We could not, however, investigate this, as we were now surrounded by fog and had to consider our return”.

Several papers carry the same story, Evening Post (4 December 1897), Hawke’s Bay Herald (6 December 1897), The Nelson Evening Mail (10 December 1897), reporting:

“Ruapehu volcano was in active eruption on Monday week according to news from Taupo. Three separate upheavals were noticed, and smoke, etc, obscured the mountain until dusk”.

The Poverty Bay Herald, (18 March 1898) reports the first ascent by a women (Mrs Malcolm Ross) with the following comments about activity:

“four hours were spent on the summit of the mountain. The Crater Lake was found to be cold. Indeed there were lumps of ice floating in it and cliffs of ice 60ft high on the southern side. Mr Ross therefore thinks that the reported eruptions of Ruapehu as recently telegraphed to the newspapers are more mythical than real. On the evening before Mr Ross’ party made the ascent what was supposed to be steam was seen rising from the vicinity of the Crater Lake. On investigation the next day it was found that the supposed steam was composed of clouds of ashes blown about in the wind, and there was no sign of activity anywhere on the mountain”.

Poverty Bay Herald (31 August 1899) reports Ruapehu has been in eruption, the first time for three years. Then in September the Taranaki Herald (1 September 1899) reports:

“The New Zealand Herald’s Taupo correspondent, writing on Tuesday, says: Soon after daylight this morning Ruapehu was noticed in active eruption, sending up an immense volume of eruptive matter, which subsequently spread out umbrella shape, after rising some thousands of feet. The scene of operations is apparently at the Crater Lake, situated about the centre of the mountain. The volume continued during the day, but contained principally steam and

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smoke…Ruapehu is very erratic in its eruptiveness. It made a grand display on March 11th, 1895, which was photographed by Mr Josiah Martin, and smaller displays about six years previous, and another about three years ago”.

This story is repeated in several other papers that week.

The Wanganui Chronicle (4 September 1899) reports:

“Ruapehu was in active eruption on Tuesday, but apparently gave out smoke only. Ngauruhoe also displayed an unusual quantity of steam; it is nearly three years since Ruapehu showed activity”.

Meanwhile the Evening Post (8 September 1899) reports:

“After the phenomena which we described a day or two ago in an extract from the Auckland Herald, the mountains were hidden from view by clouds. On Wednesday, when the clouds lifted, it was perceived (says the Herald’s Taupo correspondent) that Ruapehu had ceased”.

The Marlborough Express (8 September 1899) and Poverty Bay Herald (8 September 1899) carry a story about earthquakes at Tokaanu following the recent eruptions of Ruapehu:

“Since the Ruapehu eruption there are earthquakes day and night at Tokaanu. On Tuesday there was a heavy shook and residents left their houses and camped out till daylight. Blake’s Hotel at Tokaanu had one chimney down and another shifted, crockery was smashed. There are no shakes at Taupo”.

In a review article by Mr Malcom Ross in the Otago Witness (5 June 1907) it’s reported:

“In 1898, when I ascended the mountain, there was no activity in the crater lake, and what from down below we took to be steam coming from the top of the mountain, proved to be simply volcanic ash, blown over the ridge by a strong wind. Similarly, I believe, casual observers often say that the mountain is steaming when in reality only ashes or wisp of clouds are being blown over its crest”.

The date of the ascent is not reported [possibly March].

A1.7 1900S

The Poverty Bay Herald (4 April 1900) reports a brief account of an ascent by Mr A Warbrick, who recently ascended to the top of Mount Ruapehu, visited the Wangaehu ice caves:

“I was delighted on coming on these caves, he says, as I did not believe that such a thing as an ice cave ever existed. It is hard to say how far the caves run. I walked in about two hundred yards, and as it got so dark, and the sulphur smell from the water so strong, I thought it wisest to return and get some fresh air. The interior of the cave I entered was a wonderful sight. The Wangaehu River runs out of these caves, and I have no doubt that the waters find their way from the lake on Ruapehu”.

The Auckland Weekly News published a photograph of the Crater Lake in its May 1902 publication (Figure A 1.6). The water level appears ‘high’ in the image.

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Figure A 1.6 Ruapehu Crater Lake as published in the Auckland Weekly News 8 May 1902 (p.2). Sir George Grey Special Collections, Auckland Libraries, AWNS-19020508-2-3.

The Wanganui Herald (27 January 1903) reports:

“Ruapehu has shown signs of activity recently, ejecting puffs of smoke and making rumbling sounds. Some of the residents near the locality view these symptoms with alarm others do not regard them with any sort of apprehension”.

Evening Post (30 May 1903) discussing the railway line comments:

“The first gorge is … the other two, are Manganui-o-te-ao and Mangaturuturu, the last named having the striking pure blue colour that proclaims a ‘sulphur river’— a river impregnated with sulphur from the active holes in Ruapehu, as the Wangaehu is”.

The Feilding Star (25 March 1904) and Poverty Bay Herald (26 March 1904) carry this letter:

“by Mr W Fordham (of the Public Trust Office), the writer, the manager of a station near Taihape, states that a heavy gale blew all day on Saturday, and the dust and fumes of sulphur from the neighboring mountain were ‘simply frightful.’ ‘There must have been,’ he writes, ‘some sort of an eruption going on — there were sounds as of distant thunder and the stench of sulphur was very strong — every bit as bad as at Rotorua. The whole country is obscured as if with a heavy smoke from bush fires quite thick, almost like the prelude to a heavy shower of rain. It’s not smoke nor even dust, so it’s quite evident Ruapehu is active. I have not seen anything like this since the occasion of the big scare some years ago’”.

There are no other supporting stories to confirm this activity.

The Star, Hawera & Normanby Star, and Poverty Bay Herald (19 April 1905) all report:

“Ruapehu in active eruption. A Taupo telegram states that Ruapehu is unusually active”.

The Northern Advocate and Bush Advocate (22 March 1906) report:

“March 22. On Thursday last, seeing a large column of steam rising from Ruapehu, a party ascended the mountain and found that a violent eruption had taken place. On looking across the lake, which is 500 yards wide, it was seen to

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be violently boiling near the centre. On the south side of the lake an ice cliff was shattered, and large pieces of ice came tumbling into the boiling water”.

An article in the Evening Post (22 March 1906) reports more fully:

“Auckland, 21st March. On Thursday last a large column of steam was observed ascending from Ruapehu, and it was concluded that thermal action was going on. A party was organised by Mr Meers, of London, who had made two previous ascents of the mountain. When the summit was reached it was seen that a violent eruption of a large crater at the lake had taken place, for the greater portion of the glacier and snowfields on the east side and summit were covered with a dark grey deposit and rocks. Approaching the lake the deposit became thicker and the holes larger, caused by big boulders, whilst mounds of mud at intervals rose up from four to five feet high. Looking across the lake, which is about 500 yards wide, it was seen to be violently boiling near the centre, with great wavelets of yellow-looking matter floating away, on the surface, and steam also rising from the surface. On the south side of the lake ice cliffs were shattered to pieces and huge masses of ice came tumbling into the boiling water with a terrific roar, only to soon disappear in the boiling, seething waters. The whole scene was awe inspiring in the extreme”.

A slightly fuller account but with no more detail is published in the Nelson Evening Mail (28 March 1906).

The Dominion (14 May 1936) reported an eruption on 22 March 1906 when it [Ruapehu] ejected quantities of mud over the surrounding snow.

The Otago Witness (28 March 1906) reports an ascent of Mt Egmont and comments:

“Ruapehu was quiescent. The mountain was covered with snow for more than a thousand feet, and looked very - fine towering above a low-lying sea of cloud. Apparently the recent activity of the crater lake was only a spasmodic outburst”.

An ascent reported by the Otago Witness (9 January 1907) reports the Crater Lake as:

“the lake in the centre of the ice field was not steaming perceptibly, but it was certainly not frozen over”.

The West Coast Times (28 February 1907) and then the Hawera & Normanby Star (1 March 1907) report:

“Ruapehu mountain has also been more than usually active. Immense volumes of steam have been rising from the lake, and for two or three days the whole mountain was enveloped in steam. A fine view of it was had from Ohakune”.

Further activity is inferred in the Evening Post (18 April 1907) and Wanganui Herald (18 April 1907) reporting:

“The Raetihi correspondent of the New Zealand Herald telegraphs that an interesting change has taken place in the appearance of the Ruapehu mountain. On Tuesday the mountain was capped with snow, but yesterday it was seen to have lost its whiteness and become of a bluish gray colour. There is nothing whatever to explain this extraordinary transformation, but the fact that an eruption has evidently occurred some where on the mountain. It is considered most

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probable that the hot lake on the eastern side of Ruapehu, which has recently been more than usually active, has, instead of sending up clouds of steam only, caused an upheaval of something more substantial …The lake on Ruapehu has also at intervals emitted clouds of steam; on several occasions tremendous volumes of steam issuing above the mountain top”.

The same story appears in several other papers as well, Poverty Bay Herald (18 April 1907), Colonist (18 April 1907), and Hawera & Normanby Star (18 April 1907). No further activity is apparent according to the Wanganui Herald (19 April 1907):

“A correspondent of the Auckland Herald, telegraphing from Ohakune, states that the appearance of Ruapehu remains unchanged, and apart from a slight earth tremor and underground rumble about 1130 on Wednesday night there are no further indications of eruption. The mountain was completely hidden from view today, the greater part of the time being enveloped in clouds. The steam and deposit of volcanic matter were not as large as was at first supposed”.

The Wanganui Herald (20 April 1907) reports the same activity as:

“The Mangaweka Settler’s correspondent at Ohakune wires this morning: Reports have been received here that Mt. Ruapehu has broken out in eruption. These prove to be correct. Large volumes of smoke were issuing from the crater this morning. As the crater was considered to be practically extinct, this sudden outbreak has created considerable uneasiness, more especially as it is accompanied by strange rumbling and vibrations.

In connection with the Ruapehu eruption columns of steam were observed from Durie Hill yesterday ascending from the mountain. Every few minutes there were puffs of what appeared to be flames and thick clouds of ashes shooting upwards. A gentleman who has just returned from a visit to the mountain states that the residents of Ohakune and other places on that side of the mountain had a good view of Wednesday’s outbreak, and distinctly heard the rumblings, which at times were very loud. On Thursday the mountain was quiet, but our informant himself saw the ashes which had covered the snow, and thus changed the colour of the mountain. On Friday, there were dense columns of steam and ashes to be seen, whilst the rumbling was again very pronounced”.

Mr H Hill comments in the Poverty Bay Herald (20 April 1907):

“The telegram from Auckland published this evening with reference to the activity of Mount Ruapehu need cause no surprise. The crater on the top of the mountain, with a slope to the eastward, contains a boiling lake that at intervals, when the ebullition is most active, explodes and sends off large quantities of steam”.

While the Hawera & Normanby Star (22 April 1907) reports:

“Auckland, April 20. The correspondent of the Herald, telegraphing from Raetihi, states that clouds of steam continue to rise from Ruapehu, but no further eruption has been noticed. The outline of the top of the mountain has slightly changed, a large mass of rock having fallen some distance down the slope in the direction of Ohakune. It is not known whether this is the result of on eruption, or a landslip. A party from Ohakune will probably attempt to ascend- the mountain on Monday”.

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This is added to by the Wanganui Herald (22 April 1907):

“telegraphing from Raetihi, states that clouds of steam continue to rise from Ruapehu but no further eruption has been seen. The outline of the top of the mountain has slightly changed, a large mass of rock having fallen some distance down the slope of the mountain on Monday in the direction of Ohakune” and the Evening Post (23 April 1907) adds:

“but it is evident that the lake in the crater has been in active eruption, covering all sides with a heavy coating of bluish grey mud and ash. A large avalanche of ice from the glaciers has been tumbling down the mountain sides with a great noise, and the ice on the ‘skate’ glacier is much broken about, evidently through the shaking of the mountain during this period of eruption”.

These are the only eruptions that are known to have changed the topography when viewed from a distance.

Then on April 24 the Bay Of Plenty Times follows with:

“(NZ. Herald) Ohakune correspondent, writing on April 16, says :On the evening of April 15 an eruption of more than ordinary consequence took place from Mt Ruapehu, causing some little anxiety in the township of Ohakune. The great mountain belched forth a considerable mass of either ash or mud, which action was attended with rumblings and reports resembling cannons, and lasted for some considerable time. On viewing the mountain in the morning, it was easily discerned by the naked eye that an eruption of some magnitude had taken place. Two-thirds of the snow was covered with a black mass, resembling either mud or ashes. At early morning of the 16th the mountain was still smoking, and as the day wore on it wore into a steam, and in turn into thin vapour”.

The Bush Advocate (26 April 1907), reports a visit to the summit confirming a recent eruption:

“April 25. There are no further signs of activity on Ruapehu …The most recent ascent of Ruapehu was made at Easter time by two officers of the Public Works Department at Ohakune. They found the Crater Lake steaming, with indications of the ice walls having been undermined by hot water, and dust and a quantity of stone were found on the snow surrounding the crater. Some of the largest pieces of material were a foot in diameter. A portion of one brought back burned with a blue sulphurous flame. These stones had been ejected hot as they had melted their way into the hard snow and ice”.

Several papers carry this story. Follow up stories talked to locals and gained some perspective, for example the Wanganui Herald (27 April 1907) reports:

“Old residents in the vicinity of Ruapehu are not in the least exercised over the supposed trouble at Ruapehu, and Mr Peters, a resident of Waiouru, says that when the district was isolated little or no attention was given to such indications of activity as were reported last week. Now that the population is increasing the natural indications of activity excite alarm. The scare, he alleges, is without justification”.

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The Bush Advocate, (29 April 1907) carries a summary of past activity:

“The first big outbreak on Ruapehu recently was reported on April 10th, when the coach driver from Tokaanu to Waiouru, while passing the foot of the mountain at noon, saw a great mass of dark matter fly out of the crater, this fell aside, and gave place to clouds of steam…a great geyser action in this crater in April 1895. Vast quantities of mud and water were ejected, the action being similar to that of the Waimangu geyser, but on an even grander scale …The River Wangaehu has its source in this lake, and its sudden flooding is always connected with geyser action on Ruapehu. This stream rose suddenly in 1863 [1861], an avalanche of snow and ice tearing along its course and carrying away a bridge”.

The Poverty Bay Herald (13 May 1907) carries this short report:

“The volcano Ruapehu was showing signs of extraordinary activity on Tuesday morning last”.

The Otago Witness (8 May 1907) carries an account of Ruapehu (authored by EMD):

“Attention is being directed at the present moment to the activity of Mount Ruapehu, which forms the most prominent part of the great volcanic group in the Taupo district … The melting of the snows has caused frequent overflows in the streams which have there source in the ice fields and in the Crater Lake. One of the most remarkable of streams is the Wangaehu, which is supposed by some authorities to take its rise in the crater of Ruapehu. Others maintain that it springs from a great mass of rock called the Black Rock, which crowns a long narrow spur dividing the source of the Waikato River from a mineral spring which flows on an independent course to join the Wangaehu. It is also subject to sudden rises and changes in volume, not only from the melting of the snows, but from the geyser-like action of the Crater Lake near the summit of the mountain. This lake has been observed with intense interest — observations which may be serviceable at the present time. Several points are in dispute about its action, but the bulk of authority goes to show that the crater contains an intermittent geyser, possessing something of the nature of that which at Waimangu was so long a centre of interest. When the geyser uses, there is naturally much disturbance, and when it rises with unusual force, floods occur, the Wangaehu overflows, and mischief possibly occurs. The Crater Lake varies in temperature, observations describing the waters as temperate, hot, or cold, according to the conditions under which it is examined”.

The Otago Witness (22 May 1907) reports from Mr M Ross (19 May):

“a conversation with Mr Peters, who has closely observed the volcanoes for several years, were sufficient to convince us that the recent out break on Ruapehu was nothing more than one of the ordinary geyser like eruptions of the Crater Lake”.

The same paper published a photo on May 8 (Figure A 1.7).

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Figure A 1.7 Otago Witness 8 May 1907: The Crater Lake on Ruapehu recently in violent eruption. The lake is surrounded by walls of ice, about 200 ft in thickness. The crevassed glacier in the foreground leads down towards the source of the Wangaehu River. (Photo: Mr Malcom Ross).

In a review article by Mr Malcom Ross in the Otago Witness, 5 June 1907 it’s reported that:

“The recent activity has, undoubtedly, been due to similar geyser action; but the explosion in comparison with that of 1895 has been of a minor character”.

The Hawera & Normanby Star, Evening Post and Nelson Evening Mail (19 July 1907) carry the same story:

“A telegram states that Mounts Ruapehu and Tongariro seem to be in active eruption. There was an explosion at 4 o’clock yesterday, and a slight earthquake was also felt in Auckland yesterday”.

It is not clear from which volcano the explosion occurred, most likely Tongariro.

The Feilding Star (18 March 1908) reports:

“On Saturday morning the snow around the centre hummock of Mount Ruapehu was of very dark hue, and some spectators at Raetihi thought they discerned clouds of smoke rising from that portion of the summit in which the crater is located. This phenomenon is similar to that which occurred some eight months ago, when it was the general opinion that the mount was in slight eruption”.

The Feilding Star (24 March 1908) reports on a climbing expedition:

“It was reported that Ruapehu had been recently in active eruption, but the only indications of this noticed by the party, were the sulphur fumes, so very distinct even on the ridges at an elevation of about 5000 to 6000 feet above sea level.

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The direction of the gale was complete evidence that these fumes could only originate on Ruapehu”.

The Otautau Standard and Wallace County Chronicle (5 January 1909) reports:

“Only last year Mount Ruapehu was active and on June 10th, 1886, there occurred the disastrous eruption of Tarawera”.

An appendix to the 1909 Department of Lands Annual by H. E. Girdlestone, (Assistant Surveyor) entitled the Mountains of the Tongariro National Park: an account of their many attractions, with notes regarding the various routes and maps illustrating same: Reports the following about the Crater Lake:

“In about twenty-five minutes’ walking across snow we reached the lake. In previous visits this was a beautiful blue-green colour, and some of the party who slid down the snow-fall on the east reported that the water was only just lukewarm; but this time the whole place had the appearance of having been churned up, and steam was rising from the surface slightly, though this would probably happen at a very low temperature up there”.

It appears the trip was made in December 1908.

A1.8 1910S

An account of eruptive activity from Ruapehu in February 1910 is refuted by a story in the Hawera and Normanby Star (8 February 1910) which quotes:

“Taihape, February 8. With reference to the alleged eruption of Ruapehu, Mr Smith, member for the district, met Mr Lowe, District Railway Engineer, today, who has just returned from a trip to the top of the mountain. He spent an hour and a half there, but saw no indications of a disturbance”.

Poverty Bay Herald (9 February 1910) reports this activity from Ruapehu:

“At 1130 am on Friday Ruapehu, for the first, time since 1886 started active eruption. Looking at it from Raurimu, a huge column of steam is ascending, from behind the two peaks, locally known as the ‘Maiden’s Breasts’. At 1230 the side of the mountain was bare of snow, though it is still lying on the side towards Ngauruhoe. It is a magnificent spectacle. The sky is cloudless, except, for the huge pall of steam, and this is increasing every hour. The general opinion here is that the bottom of the lake has blown but, but whether this is true or not it is impossible at present to say. Mr E. Gould, who has been in the district for many years says that there was some steam erupted 1894 [1895], but neither that nor the 1886 eruption was on anything the awe inspiring scale of the present one”.

Poverty Bay Herald (10 February 1910) reported:

“The recent eruption of Ruapehu was clearly seen from Wanganui. An immense, column of steam was discernable rising to an enormous height above the mountain. On Monday the mountain was only dimly outlined through the haze, but there was no visible sign of volcanic activity”.

The stationmaster at Waiouru states that he saw steam come from Ngauruhoe over Ruapehu. Then a change of wind took it away, giving the appearance of it emanating from the latter. The indications point to the disturbance being entirely connected with Ngauruhoe.

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This is further reported in the Evening Post (12 February 1910):

“A writer in the Auckland Star states that the reported eruption of Ruapehu is discredited by one who climbed the mountain on Sunday, and by the stationmaster at Waiouru. The climber found the lake on the top cool enough for him to bear his hand in it. The vagaries of the wind are considered to be responsible for the apparent issue of the Ngauruhoe steam from Ruapehu”.

An article in the Ruapehu Bulletin (4 January 1911) reports the first climb of the season (assumed to be late 1910), where the party reports:

“the snow for several chains towards the Wangaehu Glacier was covered with black dust ... from the west side of the crater came yellow and black mud, and this spread out over the lake .. noise like that of falling earth ... rumblings continued ... came up thick red mud, which bubbled like boiling porridge”.

The Poverty Bay Herald (29 June 1918) reports:

“Mount Ruapehu commenced emitting a huge column of steam at 10 this morning, rising to a height of about a thousand feet. It is plainly visible from Taihape, some forty miles away, making an impressively brilliant sight. The emission appears to be on the northwestern side”.

A1.9 1920S

The Ashburton Guardian (11 October 1921) reports:

“Mount Ruapehu, which is reported as having sent up a ‘shot’ a few days ago, is considered by some who have climbed it during the last few years to be gaining in activity. Mr W Salt, president of the Ruapehu Ski and Ice Club, who has made a large number of ascents in recent years, says the Crater Lake appears more active each time he visits it. When members of the Tararua Tramping Club climbed to the crater in August last it appeared to be much more active than when several of them had seen it last, some years previously. Until about 1887 it was not known that an active crater existed in Ruapehu. Mr R Speight, of Canterbury College in describing the geology of the National Park, expressed opinion that Ruapehu will become active again; perhaps not in the near future, but almost certainly after a long space of time”.

A photograph dated as circa 1920s (Figure A 1.8) shows a relatively cool but full Crater Lake.

Figure A 1.8 Ruapehu Crater Lake, Photographs taken circa 1920s by W H Thorley. Ref: 1/2-070107-F, Ref: 1/2-070123-F. Alexander Turnbull Library.

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The Ashburton Guardian (27 October 1921) reports:

“Wellington October 26. The importance of having means by which to predict disturbances in the volcanic district of New Zealand, and the urgent need for an observatory, particularly in view of the increased activity at Mount Ruapehu, was stressed at the annual meeting of the Board of Science and Art today. Professor Marsden, during the course of a statement regarding a Volcanological Observatory …Mr PS Morgan pointed out that when Ruapehu was first visited 60 or 70 years ago there was no sign of activity, but since then a lake had formed. An investigation was very necessary. The board then discussed in committee the question of finding money, to carry out the proposals”.

In an unidentified clipping from 14 February 1925 (possibly the Wanganui Herald) there are reports of two observed eruptions by road men working near Waimarino Plains during the previous week; evidence of tide marks up to 20 ft on the bank of the Wangaehu River and from climbers of ice cave collapses during their lake visit. The climbers do not record any observations of eruptive activity, and some of the party had visited the lake before. Stillwell et al. (1954) in the Tangiwai report attributes this flood to blocking of the cave by the fall of ice. If there is eruptive activity associated with these reports it maybe minor.

A newspaper clipping from Evening Post (May 1926) quotes Blyth, indicating a very cold, but not frozen lake. It also summarises several climbs indicating the lake was warming from 1920 to 1922, being warmest in 1922 and cooling since then. There is no mention of any eruptive activity during that period.

A1.10 1930S

The Dominion (14 August 1934) reports activity in August (see below) and also mentions the lake was steaming strongly in June 1934 while Ngauruhoe was erupting. There is no suggestion of eruptions.

The Dominion (14 August 1934) reports a steam column to between 300 and 700 ft above the lake on 11 August, and observations from climbers who reported the lake had changed from, ‘the normal blue colour streaked with sulphur, to muddy brown like a river in flood’. The sides of the crater bore no evidence of the eruption.

The Evening Post (12 May 1936) reported past activity on 11 August 1934 when steam columns rose 300-700 ft. The lake was found to have changed from blue to muddy brown, but there was no ejecta observed on the snow.

The Evening Post (12 May 1936) reported eruptive activity that cast mud over an area of a square mile, and left the lake very much clearer. The activity was in the past two days. The distribution of the mud was helped by the winds [? directed activity]. Risberg reports in the Tongariro Park Boards annual report (Robertson, 1937) details of the summit and assigns a date to May 9. Blue black mud deposited beyond Cathedral Rocks was 3 inches thick and showed signs of ‘washing’.

The Dominion (14 May 1936) reported the lake had lost its colour due to activity. The Auckland Weekly News (20 May 1936) published a photograph of the Crater Lake showing discoloured snow near the lake (Figure A 1.9 and Figure A 1.10)

In an article about activity in 1940 the Dominion (30 May 1940) reports previous activity on 11 May 1936 when the snow slopes where covered for an area of a square mile with a layer

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of dark grey mud (? May 9 event) and also reports previous activity in August and December 1934, and February 1935. The style of activity is not reported.

The Dominion (8 January 1938) reports climbing trips and people swimming in the Crater Lake.

Figure A 1.9 Image of Ruapehu Crater Lake reproduced in the Auckland Weekly News 20 May 1936 (p.48). Sir George Grey Special Collections, Auckland Libraries, AWNS-19360520-48-2.

Figure A 1.10 Image of Ruapehu summit area reproduced in the Auckland Weekly News 20 May 1936 (p.48). Sir George Grey Special Collections, Auckland Libraries, AWNS-19360520-48-1.

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A1.11 1940S

The Dominion (30 April 1940) reports an eruption in the last week that produced dark streaks on the glacier and Pare-te-tai-tonga. Guides then reported snow for about a mile was covered in blue mud, in places over 6 inches deep. The lake was described as considerably disturbed. GNS Office file (T20/502 Newspaper) holds several photos of the summit area after the eruption.

The Ohakune Times (11 August 1942) reports a mild eruption the previous day, covering Girdlestone and Mangaehuhu Glacier. The same article also reports an eruption in April 1940 and May 1936.

A copy of a letter on file T20/502 reports steam eruption(s) with shower of mud and stones reaching from Dome to Cathedral Rocks in late September 1944. Gregg et al. (1960) reports small outbursts from the crater on 10 August 1942 and October 1944. The October 1944 activity is also reported in Reed (1945) and sourced to the Visitors’ Book, Ruapehu Ski Club.

Newspaper records for the period 8 March 1945 to 17 March 1946 and correspondence in NZGS files are summarised in detail by Johnston (1997a, b); only references to discreet eruptions or episodes are discussed below.

A long plume of steam noted blowing to the east and the eastern slopes of the volcano covered by mud and ash, was reported by Commander F. Allen of United Airways, on a flight from Auckland to Wellington on 8 March 1945 in the Evening Post (12 March 1945). The Taihape Times (12 March 1945) reports that staff at Waiouru Military camp noticed considerable volumes of steam and ‘smoke’ steaming away from the summit the same day. Steam emissions observed on 9, 10 March are reported by the Taumarunui Press (22 March 1945) as ‘Immense volumes of steam with dark coloured blotches, evidently debris, were being erupted up to about 2000 ft on a very wide base.’ This was observed by Mr E. Lightband of Ohakune.

A lava ‘cone’ is observed emerging from the lake on 19 March. The eruption of steam accompanied by loud rumblings or cracking noises, explosions of mud, ash and occasional larger fragments alternated by quiet periods of steam, with steam escaping under great pressure is summarised by Reed (1945). Small scale explosions were observed on March 22 (A. Manson quoted in NZ Herald 22 March 1945). Strong explosive activity on 26 March (columns reported 6-8000 ft) appears to destroy the cone that was present above lake level (Reed, 1945). Intermittent small scale explosive activity continued in late March with activity observed on 31 March (Figure A 1.11). In April activity is recorded on April 1, 2, 15 and 16 (Reed, 1945; Gregg et al., 1960; Johnston, 1997a). No further activity is recorded until May.

A layer of fine, sandy ash discolouring the snow on the north side of Ruapehu down to 4000 ft is reported in the Dominion (10 May 1945). An island within the Crater Lake is reported by 7 May (Oliver, 1945). The renewed activity had intensified by 9 May to be equal to the most violent outburst of March. Steam and fine ash were reported pouring out in a continuous column and loud rumblings could be heard at the Chateau (Dominion, 10 May 1945). Columns are reported from distal sites, along with ashfall on May 12 and 13 (Johnston, 1997a). Then on 14 May incandescence is observed and tall eruptions columns are formed latter in the day (Dominion, 15 May 1945). No further activity is reported until June. There are no reports of lahar activity.

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Figure A 1.11 Copy of the painting made by Ashley Cunningham of the 31 March 1945 eruption he and friends witnessed (Cunningham, 2000).

Activity was noticed in the evening of 17 June by residents of Ohakune who remarked that it looked like a picture of the Vesuvius eruption (Ohakune Times, 22 June 1945). Then on June 19, a steady volume of what appeared to be a mix of dust and steam was observed coming from the crater, although there were no very high or large explosions. Reports of a light dusting of ash in Taupo appeared in the NZ Herald (20 June 1945). Dense clouds of dirty ‘smoke’ belching out furiously were reported by Ohakune residents (Ohakune Times, 22 June 1945).

“More activity than for some time... steady volume of steam and dust rising... northern slopes covered by dust” is reported in the Ruapehu Ski Club (R.S.C.) Bulletin, September 1945. On 20 June large rocks were observed being thrown out of the crater with slopes of the mountain blackened by volcanic ash (Wanganui Herald, 21 June 1945). A tremendous pall of smoke over the summit was reported stretching away to the horizon on the Ohakune side in the Ohakune Times (22 June 1945). The R.S.C. Bulletin (September 1945) reports:

“T.H Bierre (member) while on the Dome saw boulders ‘the size of the Hut’ thrown up to fall back into the vent. Stones 3 feet across were seen on the upper part of the Glacier. A coating of ash made skiing impossible on the Chateau side of the mountain”.

Further ashfalls are reported 27, 29 and 30 June. By 1 July the lava extrusion had displaced much of the former lake with large flows of water from the lake basin. Incandescence was reported at night and many small explosions were noted (Oliver, 1945). This continued through 4 July.

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After July 19 most activity reports discuss ashfalls, reflecting the change in activity once the Crater Lake was removed (Figure A 1.12). A particularly large ash column is reported by Mr W E Hill on 20 July in a letter to NZGS, reaching over 20,000 ft. Ash eruptions continue most days until around 22 August when activity appears to have declined (Beck, 1950), but the accounts tabled by Johnston (1997a) don’t fully support this, as activity continued much the same into September. By 9 September one more active central vent dominated and was the source of explosions and ash emissions. After 16-17 September activity was stronger and continued during the latter part of the month (strongest around 28-29 September) and into October. On 14 and 15 October Healy reported ash columns to around 2000 ft (monthly report RUA47/01). The tempo varies but it is dominated by explosions and ash emissions and reports of incandescence. The active vent was enlarging during this time. Fine weather allowed for good observations of stronger activity on November 6 (possibly the strongest of the eruption). Explosive activity and reports of ashfall continued through November and into December with the last ash emission being reported on 29 December (Beck, 1950; Johnston, 1997a). Healy reported a lakelet forming on 18 December and this is confirmed by further observation during January 1946. In February 1946 the lake is reported as a bright yellow-green in colour.

Figure A 1.12 View of the ash cloud from the eruption of Mt Ruapehu, from near Waihohonui Hut, during a deer hunting expedition. Photograph taken in 1945, Bruce Valentine Davis (http://natlib.govt.nz/ records/22737221).

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Ash eruptions that discolour the snow were reported on 18 April 1946 by the Taranaki Daily News and Wanganui Herald (18 April 1946). Small explosions were occurring through a dark grey lakelet on 31 May. The Manawatu Daily (15 June 1946) reported further small ash events and explosions being heard in Ohakune and suggested mild activity may have been occurring for the previous two months. On July 6 weak geysering continued in a larger lake (Healy, 1956). The Taranaki Daily News (4 September 1946) reported steam emissions, but more importantly this is the first fine weather for over a month allowing observations. The Wanganui Herald, Wanganui Chronicle and the Taranaki Daily News report similar on 2 and 5 October 1946. A similar story also ran on in the Evening Post (21 November 1946), quoting observations from Taupo.

Healy climbed the mountain on 24 January 1947 and reported that the lake was increasing in size. The NZ Herald (19 February 1947) reported steam columns and discoloured snow and unconfirmed reports of explosions from 17 February. On 17 March 1947 the Evening Post and NZ Herald reported explosive activity on March 15-16 that generated ash and steam columns to 5-7000 ft. The Dominion (30 April 1947) report a telegram dated 29 April:

“a crater explosion yesterday [ 28th ] morning sent a column of smoke 10,000ft just short of the column sent up on Saturday [ 27th ]. Trampers report fresh rocks on the snow”.

The Taranaki Herald (2 June) reports:

“Dense billowing masses of steam, smoke and ash ... on Saturday [31 May] … soaring to heights of 1500ft … billowing to about 12,00ft … a dark smear of ash could be seen falling on the snow”.

A photograph dated August 1947 shows a small lake has started to fill the active crater (Figure A 1.13).

Figure A 1.13 Aerial view of the crater, Mt Ruapehu, photographed by Whites Aviation in August 1947. Photograph Ref: WA-08904-F. Alexander Turnbull Library, Wellington, New Zealand.

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A single explosion, producing a steam column to 4-5000 ft was observed on 23 January 1948 and reported in the NZ Herald (24 January 1948). Small steam columns to less than 3000 ft are reported on the 6, 7 and 8 February in the NZ Herald (9 February 1948). Further activity is reported on the 10 February when observers saw several events from Taupo (NZ Herald, 11 February. 1948). Several reports based on climbing reports confirm a growing crater lake in 1947-48.

Allen (1948) reported and illustrated (photo) an explosive steam column at 1120 am on 1 May 1948. As Ngauruhoe was also erupting more strongly at this time there were no further observations of Ruapehu. Gregg et al. (1960) reported (based on newspapers) ‘crater lake steaming’ in May and September 1949.

A1.12 1950S

Gregg et al. (1960) reported: ‘crater lake steaming’ for 19 June 1950, based on a newspaper account. A tramper returning from a TNP visit is quoted in the NZ Herald (26 June 1950):

“The northern side of Ruapehu is black with ash thrown out in the last two or three days [24th, 25th]”.

Healy (1956) also reported another event on 19 March 1951 (Evening Post, 19 March 1951). Mr GH Thompson recounted in evidence to the Tangiwai enquiry (Thompson, 1954) a description of a typical phreatic eruption he observed in July 1952 while climbing on the slopes of Pare-te-tai-tonga. About 30% of the lake surface was domed up about 60 feet, before a great burst of steam. He also describes the lake surface as surging with wisps of steam.

On 24 December 1953 the outlet dam failed and a significant flood was generated in the Whangaehu Valley, eventually destroying the rail bridge at Tangiwai. The lake was full at the time (Figure A 1.14).

Figure A 1.14 This panorama shows the swollen lake in Labour weekend 1953, about two months before the Tangiwai disaster in December 1953. (Peter Otway collection)

In October 1954 several observations of steam columns and surging in the lake are reported in newspapers (Christchurch Star Times, 7 October; Rotorua Post, 8 October; The Press, 11 October; NZ Herald, 13 October 1954). Steam emissions often obscured lake views. The next reported observation of steam is in October 1956 (NZ Herald, 23 October 1956). The NZ Herald (18 November) reported a small eruption on 18 November that blackened snow around the lake rim. However EF Lloyd climbed the volcano on 19 December and saw no evidence of the event.

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A tramper records a ‘green eruption in the crater lake’ on 28 January 1958. They also carried on to explore the outlet and admired the magnificent ‘ice cavern’. In response to reports of an increase in the lake level the crater was overflown on 17 September 1958. Observations by J Healy suggested no changes had occurred. Starting on 21 May 1959 steam clouds and ash was reported from Ruapehu (The Rotorua Post, 21 May 1959; NZ Herald, 22 May 1959) with further reports of steam on June 2 (NZ Herald, 3 June 1959; The Daily Post, 3 June 1959) and June 9 (NZ Herald, 10 June 1959). All reported steam columns, with minor ashfall and some sounds. EF Lloyd climbed the mountain on 12 June finding the lake a dark metallic grey, almost black colour and discoloured snow around Pyramid Peak, confirming minor activity. Activity was reported through until at least 26 August, when EF Lloyd observed steams columns from Orakeikorako (RUA 59/04).

Activity after the end of 1959 is reported in DSIR immediate reports and other items now held on GNS files and published papers. Activity observations from those records are presented in Appendix 2 but are not presented or discussed in detail here.

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APPENDIX 2: SUMMARY OF ERUPTIVE AND LAHAR ACTIVITY AT RUAPEHU FROM 1830 TO 2012. THE ERUPTION MAGNITUDE IS A SEMI-QUANTITATIVE ESTIMATE BASED ON OBSERVED EFFECTS (SEE Table 3.4)

Date Description of Events Activity Comment Reference Scale

1830s Eruptive activity 3 Recollection from natives, quoted in Feilding Star 12.3.1895 newspapers as previous activity in articles Star 21.3.1895 during the 1895 activity

1853 February 2 Sir George Greys ascent of Ruapehu 0 Grey informed Hochstetter he had seen ‘a Mead (1970) crater with hot springs’. There is no direct reference to a Crater Lake.

Pre 1861 Indication of a large lake A Maori chief recounts his memory of the Mead (1970) lake

1861 February 13 Lake break out event Dam Lahar Gregg et al. (1960, pg 45)

Break Bridge destroyed Wellington Independent 5.3.1861

Wellington Independent (5.3.1861) suggests Taranaki Herald 2.3.1861 a snow avalanche from the mountain Crawford (1870) blocked the river (? non volcanic) Wanganui Herald 8.4.1895

Stilwell et al. (1954)

1861 May 16 Indications of ash column and night 4 Moderate to large phreatomagmatic eruption New Zealand Spectator 8.6.1861 glows Possibly lava in crater. No mention of lahars. Cook’s Strait Guardian 8.6.1861

Gregg et al. (1960)

Latter (1985)

1863 Lahar? Believed to be a wrong date, should be Skey (1869) 1861? Wellington Independent 27.7.1869

Taranaki Herald 2.10.1869

1869 October Report of glows 3 Report from Dr Hector Star 14.6.1870

Steaming, mountain throwing out Batley observed steam columns while Evening Post 9.6.1870 immense clouds of steam driving cattle, no date Daily Southern Cross 17.6.1870 Wangaehu River flood (Lennard, 1945) Cowan (1927) Report of a previous eruption in 1869 Lennard (1945) [possibly January or October], included in reports of 1 May 1889 activity Reed (1945) Gregg et al. (1960)

Hawke’s Bay Herald 7.5.1889

Taranaki Herald 11.5.1889

1870 January 12 Report of discoloured snow 3 Letter reporting discoloured snow Wellington Independent 1.2.1870

Steaming, mountain throwing out Hector also reported snow melted (lahar?) Star 14.6.1870 immense clouds of steam

1879 February First sighting of the Crater Lake, a 0 First ascent reporting the presence of a Cowan (1927) circular pool of milky water Crater Lake (Beetham and Maxwell) Lennard (1945)

1880 Steam columns 1 A letter from HC Fields describes steam Hawke’s Bay Herald 24.5.1892 columns in late 1880

1881 Steaming 1 Steam columns from the mountain Cussen (1886)

Cowan (1927)

Gregg et al. (1960)

1881 March Crater Lake steaming 0 Observations from an ascent by Mr and Mrs Hill (1895) Birch, first report of a ‘hot’ lake Cowan (1927)

Reed (1945)

Latter (1985)

1882 Warm-hot lake 0 An account of Murray’s ascent Wanganui Herald 2.9.1886

1886 January 8 Lake reported frozen 0 Account of an ascent, 200 m across Weekly News 20.10.54

Park (1887)

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Date Description of Events Activity Comment Reference Scale

1886 April 11 Crater Lake steaming and hot 0 Reports from surveyor of ‘boiling lake’ Cussen (1887) following a climb Thomson (1926)

Evening Post 12.5.1936

Reed (1945)

Gregg et al. (1960)

Latter (1985)

1886 April 16 Steam rising 1 Well defined steam columns rising several Cussen (1887) hundred feet Thomson (1926)

Marlborough Express 14.6.1886

Nelson Evening Mail 18.6.1886

Te Aroha News 19.6.1886

North Otago Times 1.7.1886

Gregg et al. (1960)

1886 May 1 Steam columns 1 Report from surveyor Wilson, steam column Hawera Normanby Star 23.7.1886 to 300’

1886 May 11-18 Steam columns-immense volumes of 1 Observations from residents at Wanganui Chronicle 19.5.1886 steam Tapuharaeru, covering past ‘weeks’ Evening Post 19.5.1886

Taranaki Herald 19.5.1886

1886 June Steam columns 1 Jets of steam reported from Tarawera Star 14.6.1886 (Napier-Taupo Road)

1886 July 7 Steam reported 1 Report of activity from Mr Rochfort Star 10.7.1886

Evening Post 10.7.1886

Bay of Plenty Times 15.7.1886

Grey River Argus 15 .7.1886

Wanganui Herald 17.7.1886

1886 July 9 Steam columns 1 Summary of observations during July in Wanganui Chronicle 20.7.1886 letter from GF Allen Wanganui Chronicle 26.4.1894

1886 July 20 Steam columns 1 Observations from 20 July of columns Wanganui Herald 21.7.1886 ascending for several hours

1886 July Wangaehu River reported as clean and Letter from McDonnell describes how the Wanganui Chronicle 29.7.1886 useable – Waikato becoming turbid river systems have changed Wanganui Herald 19.8.1886

Wanganui Chronicle 23.8.1886

Hawke’s Bay Herald 24.5.1892

1886 August 23 Steam columns and geysering activity 2 Steam from geysering type activity, letter Wanganui Chronicle 23.8.1886 from Mr J Morgan

1886 September 29/30 In a state of eruption 2 Steam columns reported rising to great Star 29.9.1886 heights Bay Of Plenty Times 30.9.1886 Disputed in the Waikato Times Waikato Times 30.9.1886

1887 May Geysering activity 2 Dr Marshall refers to geysering in 1887 Otago Witness 1.5.1907

1887 May 8 Steam columns 1 A recollection date from correspondent, Wanganui Herald 13 March 1895 1887 was less active than 1895

1887 June 22 Steam clouds reported 1 Report from Wanganui of large steam clouds Ashburton Guardian 22.6.1887

Wanganui Herald 2.7.1887

1887 October Illustration of steam column above See Figure 5.1 Illustrated Australian News Ruapehu 15.10.1887

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Date Description of Events Activity Comment Reference Scale

1889 April (22, 29, 30 April) Geyser like eruption(s) from the Crater 3 Hill reports blue muds and boulders on the Marlborough Express 2.5.1889 Lake snowfields. Wanagehu in flood 3 or 4 ft Evening Post 2.5.1889 (Reports of rapid flooding). Lahars reported for 22, 29 and 30 April Poverty Bay Herald 2.5.1889

Steam eruption, floods in Wangaehu Hill (1895)

Reed (1945) 1889 May 1 Lahar reported Notes dates 22, 29, 30 April and 1 May are reported. Its likely activity occurred on all Gregg et al. (1960)

dates, but it’s not totally definitive. Latter (1985)

Hawke’s Bay Herald 1.5.1889

Feilding Star 4.5.1889

Wanganui Herald 25.5.1889

Inangahua Times 3.6.1889

1889 June 1 Steam eruption(s), Wangaehu River 2 Reports of active geysers at regular intervals Wanganui Herald 1.6.1889 flow decreases at Ruapehu Bush Advocate 6.6.1889

1889 August Mud and boulders of blue clay on the 3 Similar to May eruption Cowan (1927) ice and snow, Wangaehu floods Evening Post 12.5.1936

1889 December Small flood noted in upper Wangaehu 3 Newspaper report of small flood and Wanganui Chronicle 6.12.1889 River discoloration of river

1890 March 20 Crater Lake steaming 0 A detailed report of an ascent includes Reed (1945) descriptions of the crater lake, eruption Debris, boulders and blue muds Gregg et al. (1960) deposits (1889) and the Wangaehu valley Crater lake hot and active, evidence of and ice cave Hill (1895) recent eruptions, muds and high tide Southland Times 21.3.1890 marks Wanganui Herald 21.3.1890

Hawke’s Bay Herald 27.3.1890

Hawke’s Bay Herald 4.4.1890

1891 January Dense smoke was coming from the 1 An account of an ascent, it’s reported as Wanganui Chronicle 23.1.1891 crater Ruapehu, but may be Ngauruhoe?

1892 February 4 Steam columns reported 1 Taupo district reports increased thermal Evening Post 5.2.1892 activity, immense volumes of steam

1892 May Summary account of ascents Various recollections, no current activity Hawke’s Bay Herald 24.5.1829

1895 March 10 Steam & ash eruption, flood in 5 Steam column 6000 ft, Whangaehu flooded, Evening Post 11.3.1895 Wangaehu River which later became also Mangtoetoenui and Manga-nui-a-te-Ao Wanganui Chronicle 14.3.1895 useable for stock and Wanganui River Feilding Star 16.3.1895 Crater Lake reduced in size Wanganui Herald 16.3.1895 Ashfalls Wanganui Herald 22.3.1895

Otago Witness 1.5.1907

Otago Witness 5.6.1907

Thomson (1926)

Cowan (1927)

Reed (1945)

Gregg et al. (1960)

Latter (1985)

Illustrated Australian News

Evening Post 12.5.1936

1895 March 14 Explosive activity from crater 3 An account from an ascent Star 19 .3.1895

1895 March Activity continues 2 An account on an ascent, unable to see the Wanganui Herald 22.3.1895 lake as it is reduced in size, steam and Feilding Star 19.3.1895 discoloured snow

1895 April Great geyser action Brief report of an eruption, mud and water Bush Advocate 29.4.1907 ejected (most likely the March event)

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Date Description of Events Activity Comment Reference Scale

1897 Crater Lake steaming Based on Friedlaender’s visit (normal state?) Friedlaender (1898)

Gregg et al. (1960)

1897 January No unusual activity 0 A story on the Te Maari eruption reports no Star 6.1.897 activity at Ruapehu

1897 April Steam rising from lake 0 Observations from an ascent, lake was hot Gregg et al. (1960)

Lowe (1897)

1897 August A dark smoke from Ruapehu 1 Summary telegram from Taupo, comments Poverty Bay Herald 19.8.1897 Ruapehu emitting dark smoke

1897 September Eruptive activity in lake 3 Report of an ascent, Wangaehu Glacier was Poverty Bay Herald 30.9.1897 covered yellow and many holes, explosion heard

1897 December Eruption columns 3 Three eruptions reported from Taupo, Evening Post 4.12.1897 including smoke obscuring the view Hawke’s Bay Herald 6.12.1897

Nelson Evening Mail 10.12.1897

1898 March 13 Lake appears cold Report of the 1st ascent by a women Poverty Bay Herald 18.3.1898

Otago Witness 5.6.1907

1899 August Eruption columns, umbrella shape 4 A tall steam column is reported (thousands Poverty Bay Herald 31.8.1899 of feet) Wanganui Chronicle 4.9.1899

Evening Post 8.9.1899

Taranaki Herald 1.9.1899

1903 January Rumblings and smoke reported 2 Steam columns and sounds The Wanganui Herald 27.1.1903

1903 March 1 Eruption, flood in Whangaehu 3 A black cloud from the Crater Lake and a Gregg et al. (1960) flood in the Whangaehu Latter (1985)

1904 March 25 Possible ashfall? 3 Newspaper account that suggests there is Feilding Star 25.3.1904 ashfall from Ruapehu Poverty Bay Herald 26.3.1904

1905 April 25 Unusually active 2 A short telegraph message, reports Star 19.4.1905 Ruapehu in eruption Hawera Normanby Star 19.4.1905

Poverty Bay Herald 19.4.1905

1906 March 15 Steam eruption 3 A report of an ascent confirms eruptive Reed (1945) activity, and the impacts on the summit Mud and rocks ejected onto snow, no Gregg et al. (1960) lahars reported Northern Advocate 22.3.1906

Bush Advocate 22.3.1906

Nelson Evening Mail 28.3.1906

Evening Post 22.3.1906

Thomson (1926)

Dominion 14.5.1936

Latter (1985)

1907 January Crater Lake quiet 0 Report of an ascent Otago Witness 9.1.1907

Newspaper account suggesting there has been activity, snow discoloured

1907 February Crater Lake steaming 2 Immense volumes of steam for two to three Gregg et al. (1960) days Latter (1985)

West Coast Times 28.2.1907

Hawera Normanby Star 1.3.1907

Speight (1908)

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Date Description of Events Activity Comment Reference Scale

1907 April 15 Eruptions large enough to cover snow, 3 Several newspaper accounts of eruption Evening Post 18.4.1907 avalanching/landslides, no lahars affects, continued for some days. Possible (16-22) Wanganui Herald 18.4.1907 mentioned started on the 10th, with largest events on 15th. Wanganui Herald 19.4.1907

Collapse of Skate Glacier Wanganui Herald 20.4.1907

Wanganui Herald 22.4.1907

Hawera Normanby Star 22.4.1907

Evening Post 23.4.1907

Bay of Plenty Times 24.3.1907

Bush Advocate 26.4.1907

Bush Advocate 29.4.1907

Poverty Bay Herald 13.5.1907

Otago Witness 22.5.1907

Gregg et al. (1960)

1907 May Reports of activity in early May 2

1907 July Crater Lake steaming 2 Newspaper accounts for 19 July indicate Gregg et al. (1960) further activity Nelson Evening Mail 19.7.1907

Evening Post 19.7.1907

Hawera Normanby Star 19.5.1907

1908 March Minor activity 3 Newspaper accounts suggesting there has Feilding Star 18.3.1908 been activity, snow discoloured Feilding Star 24.3.1908

1908 December Crater Lake churned up and steaming 0 Account from a climb by Girdlestone Girdlestone (1909)

1909 March Geysering activity 2 Thomson (1926)

1910 February 9 Crater Lake steaming 2 Check for pre 8 February info Hawera Normanby Star 8.2.1910

Activity is discredited by a climber Poverty Bay Herald 9.2.1910

Poverty Bay Herald 10.2.1910

Gregg et al. (1960)

Evening Post 12.2.1910

1910 February 28 2 Eruption recorded in Latter listing Latter (1985)

1910 (late) Eruptive activity in lake 2 Snow discoloured, activity in lake Ruapehu Bulletin published yellow/black mud ejections 4 January 1911

1918 June 29 Steam eruption(s) 2 Steam columns observed, <10000 ft Poverty Bay Herald 29.6.1918

Gregg et al. (1960)

Latter (1985)

1921 October 1 Steam eruption(s) 2 Steam shot, climbers report more active Reed (1945)

Gregg et al. (1960)

Latter (1985)

Dominion 5.10.1921

Ashburton Guardian 11.10.1921

1925 February 3 Eruptive activity and flooding in 3 Newspaper quote for activity and flooding Newspaper 14.2.1925 Whangaehu moderate phreatomagmatic eruption Thompson (1925)

Stillwell attributes flood to ice cave collapse Stillwell (1954)

Latter dates this as 22 January Gregg et al. (1960)

Latter (1985)

RUA 70/11

1926 May Lake reported as frozen over Thomson (1926)

Newspaper account of been icy cold, but not Evening Post 7.5.1926 frozen

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Date Description of Events Activity Comment Reference Scale

1934 June Crater Lake steaming 2 Newspaper report of activity in June and Gregg et al. (1960) August Dominion 14.8.1934

1934 August 11 Steam eruption(s) 2 Steam column 300-700 ft, change to lake Dominion 14.8.1934 colour Evening Post 12.5.1936

Reed (1945)

Gregg et al. (1960)

1934 December Steam eruption(s) 2 Newspaper report of previous eruptive Reed (1945) activity, no details of size/style Gregg et al. (1960)

Dominion 30.5.1940

1935 February Steam eruption(s) 2 Newspaper report of previous eruptive Reed (1945) activity, no details of size/style Gregg et al. (1960)

Dominion 30.5.1940

1936 May 9 Moderate phreatomagmatic eruption 4 Much of the summit snowfield covered with Evening Post 12.5.1936 mud, 2-3000 tons ejected Dominion 14.5.1936

Ohakune Times 11.8.1942

Robertson (1937)

Reed (1945)

Gregg et al. (1960)

1940 April (late) Moderate phreatomagmatic eruption, 4 Mud and small stones thrown onto Dominion 30.5.1940 lahar Whakapapa, Mangaturuturu and Reed (1945) Whangaehu glaciers Gregg et al. (1960)

GNS file T20/502

1942 August 10 Steam eruption(s) 4 Reports that muds covering Girdlestone and Ohakune Times 11.8.1942 Mangaehuhu Glacier Gregg et al. (1960)

Latter (1985)

1944 September (late) Steam eruption(s) 4 Shower of mud an stones, Dome to GNS file T20/502 Cathedral Rocks. Letter 12.10.1944.

1944 October Steam eruption 3 Sourced by Reed from visitor book Reed (1945)

Gregg et al. (1960)

1945 March 8 Small-moderate eruption(s) 3 Upper slopes covered with mud and ash, Reed (1945) steam columns reported by aircraft Evening Post 12.3.1945

Taihape Times 12.3.1945

Latter (1985)

1945 March 9 Strong steaming-eruption(s) 3 Various reports of activity, minor activity Johnston (1997a,b) reported by RNZAF flight Taumarunui Press 22.3.1945

1945 March 10 Strong steaming-eruption(s) 3 Various reports of activity, debris on snow. Johnston (1997a,b) Crater not observed on flight. Taumarunui Press 22.3.1945

1945 March 12 Activity less than previous days 2 Activity reported as less in newspaper. Also Taihape Times 12.3.1945 accounts of felt tremors and sounds. Johnston (1997b)

1945 March 14 Strong steaming-eruption(s) 3 Various reports of activity, debris on snow Johnston (1997a)

Taumarunui Press 22.3.1945

1945 March 15 Stronger activity, maybe explosive 3 Descriptions of debris etc. Reed (1945)

Johnston (1997a)

1945 March 16 Earthquake report felt in Ohakune (many felt Taumarunui Press 22.3.1945 in recent weeks)

1945 March 18 Steam with dark coloured blotches 3

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Date Description of Events Activity Comment Reference Scale

1945 March 19 Lava cone observed in lake 3 Emergence of lava above lake Reed (1945)

Gregg et al. (1960)

1945 March 22 Small scale explosions 3 Explosive activity NZ Herald 22.3.1945

1945 March 26 Cone destroyed by explosive activity 4 Eruption columns to 6-8000 ft Reed (1945)

1945 March 31 Small scale explosive activity 3 Various reports from sources Reed (1945)

Johnston (1997a)

Gregg et al. (1960)

1945 April 1 Small scale explosive activity 3 Various reports from sources Reed (1945)

Johnston (1997a)

Gregg et al. (1960)

1945 April 2 Small scale explosive activity 3 Various reports from sources Reed (1945)

Johnston (1997a)

Gregg et al. (1960)

1945 April 15 Small scale explosive activity 3 Various reports from sources Reed (1945)

Johnston (1997a)

Gregg et al. (1960)

1945 April 16 Small scale explosive activity 3 Various reports from sources Reed (1945)

Johnston (1997a)

Gregg et al. (1960)

1945 May 5 Ash on the snow 3 First evidence of further explosive activity Dominion 10.5.1945

1945 May 7 Island reappears in lake 3 First sighting of the lava dome again Oliver (1945)

Dominion 10.5.1945

1945 May 8 Explosive activity 3 Activity intensifying Oliver (1945)

Dominion 10.5.1945

1945 May 9 Stronger activity, explosive 3 Strongest since March 1945, ash column(s) Dominion 10.5.1945

1945 May 12 Stronger activity 3 Ash columns Dominion 14.5.1945

1945 May 13 Explosive activity 3 Stronger activity Dominion 14.5.1945

1945 May 14 Incandescence and explosive activity 4 Strong steam emission, then activity Dominion 15.5.1945

1945 June 17 Small scale explosive activity 4 Reports of ash columns, explosions and Johnston (1997a) ashfall

1945 June 19 Small scale explosive activity 4 Reports of ash columns, explosions and Johnston (1997a) ashfall Ashfall in Taupo NZ Herald 20.6.1945

1945 June 20 Small scale explosive activity 4 Reports of ash columns, explosions and Johnston (1997a) ashfall NZ Herald 20.6.1945

Wanganui Herald 21.6.1945

Ohakune Times 22.6.1945

1945 June 24 Incandescence and explosive activity 4 Explosive activity from the dome, ashfalls Johnston (1997a)

Ashfall Ohakune Wanganui Herald 25.6.1945

Ohakune Times 26.6.1945

Dominion 26.6.45

1945 June 27 Ash producing activity 4 Ashfalls Johnston (1997a)

Ashfall Chateau Ruapehu Ski Club Bull. September 1945

1945 June 28 Ashfall Ohakune 4 Ashfalls Wanganui Herald 29.6.1945

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Date Description of Events Activity Comment Reference Scale

1945 June 29 Ash producing activity 4 Ashfalls Johnston (1997a)

Ashfall Waiouru Wanganui Herald 29.6.1945

1945 June 30 Ash producing activity 4 Ashfalls Johnston (1997a)

Ashfall Ohakune, Wanganui Taranaki Herald 3.7.1945

1945 July 1 Incandescence and explosive activity 3 Explosive activity from the dome Johnston (1997a)

Gregg et al. (1960)

Oliver (1945)

1945 July 2 Incandescence and explosive activity 3 Explosive activity from the dome Johnston (1997a)

Evening Post 3.7.1945

Wanganui Herald 5.7.1945

Dominion 3.7.1945

1945 July 3 Incandescence and explosive activity 3 Explosive activity from the dome Johnston (1997a)

Daily Telegraph 5.7.1945

1945 July 4 Incandescence and explosive activity 3 Explosive activity from the dome Oliver (1945)

Daily Telegraph 5.7.1945

Evening Post 6.7.1945

1945 July 19 Explosive activity, ash, incandescence 4 Active vent(s) forming in the lava intrusion Oliver (1945)

Beck (1950)

Johnston (1997a)

NZ Herald 20.7.1945

1945 July 20 Explosive activity, ash, incandescence 5 Ash columns to 20000 ft Letter on T20/502

Johnston (1997a)

1945 July 22 Explosive activity, ash, incandescence 4 Lake now gone, lave dome growth Johnston (1997a)

1945 July 23 Explosive activity, ash, incandescence 4 Rumblings and explosions Waimarino Call 24.7.1945

1945 July 24 Explosive activity, ash, incandescence 4 Ashfalls, columns to 12000 ft Waimarino Call 24.7.1945

Ashfall Ohakune

1945 July 26 Explosive activity, ash, incandescence 4 Ashfalls Manawatu Daily Times 31.7.1945

Ashfall Hawke’s Bay Auckland Star 28.7.1945

1945 July 27 Explosive activity, ash, incandescence 4 Ashfalls, columns to 5000 ft Auckland Star 28.7.1945

Ashfall Chateau, Hawke’s Bay Manawatu Daily Times 31.7.1945

1945 July 31 Explosive activity, ash, incandescence 4 Explosions, multiple vents active Wanganui Chronicle 31.7.1945

Ashfall Chateau, Ohakune Wanganui Herald 1.8.1945

1945 August 2 Explosive activity 4 Ashfalls Johnston (1997a)

Ashfall Chateau, Taihape Dominion 8.8.1945

1945 August 3 Explosive activity 4 Thick black ash emissions Johnston (1997a)

1945 August 4 Explosive activity 4 Ashfalls Taranaki Herald 7.8.1945

Ashfall Waiouru, Taihape Dominion 8.8.1945

1945 August 5 Explosive activity 5 Ashfalls, ash columns 10-12000 ft Dominion 6.8.1945

Ashfall Ohakune, Waiouru, Taihape

1945 August 6 Ashfall Ohakune, Taihape 4 Ashfalls NZ Herald 9.8.1945

1945 August 7 Explosive activity 4 Ash columns 3-4000 ft NZ Herald 8.8.1945

Ashfall Waiouru

1945 August 8 Explosive activity 4 Blocks forming craters in ice on Whakapapa Letter to Dir. NZGS 8.8.1945 Glacier Ashfall Hawke’s Bay Daily Telegraph 8.8.1945

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Date Description of Events Activity Comment Reference Scale

1945 August 9 Ashfall Hawke’s Bay 4 Daily Telegraph 9.8.1945

1945 August 11 Explosive activity 4 Ash columns 2-3000 ft, many observed Johnston (1997a)

1945 August 12 Ashfall Hawke’s Bay 4 Dominion 13.8.1945

1945 August 13 Explosive activity 4 Minor explosions and ash laden steam Johnston (1997a)

1945 August 14 Explosive activity 4 ‘erupting normally’ Johnston (1997a)

1945 August 15 Ashfall Hawke’s Bay 4 Dominion 22.8.1945

1945 August 16 Explosive activity 4 Increase in strength of activity Johnston (1997a)

Letter to Dir. NZGS

1945 August 17 Explosive activity 4 Explosions, blocks and ash 800-1000 ft Johnston (1997a) above vent Ashfall Taupo Letter to Dir. NZGS

Ashfall Chateau, Waiouru NZ Herald 18.8.1945

1945 August 19 Ashfall Taupo 4 Ashfall Taupo Letter to NZGS from R. Ward

Johnston (1997a)

1945 August 20 Explosive activity 5 Explosions, ash columns 3-500 ft and larger Johnston (1997a) to 12000 ft

1945 August 21 Explosive activity 4 Electrical activity in 10000 ft columns Johnston (1997a)

Ashfall in Rotorua, Ohakune Wanganui Herald 22.8.1945

Rotorua Morning Post 22.8.1945

1945 August 22 Explosive activity 4 Explosive activity continues, many reports of Johnston (1997a) ashfall issues Ashfall Ohakune, Wanganui Wanganui Herald 22.8.1945

Taihape Times 22.8.1945

1945 August 23 Explosive activity 5 Ash columns to 20000 ft, blocks 1000 ft Johnston (1997a)

Ashfall Wellington Dominion 24.8.1945

1945 August 24 Explosive activity 5 Similar activity sustained Johnston (1997a)

Letter to Dir. NZGS

1945 August 25 Ashfall Ohakune, Palmerston North 4 Auckland Star 25.8.1945

Manawatu Standard 27.8.1945

1945 August 26 Explosive activity 4 Ashfalls continue Johnston (1997a)

Ashfall Ohakune Waiarapa Times 27.8.1945

1945 August 27 Explosive activity 4 Small decline, activity continues Johnston (1997a)

Ashfall Ohakune

1945 August 29 Explosive activity 4 Decline continues in level of activity Johnston (1997a)

1945 August 31 Explosive activity 4 Activity moderate with several explosions Johnston (1997a)

Letter to Dir. NZGS

1945 September 1 Explosive activity 4 Activity decreasing Johnston (1997a)

Letter to Dir. NZGS

1945 September 3 Ash emission 4 Activity decreasing Johnston (1997a)

1945 September 4 Ash emissions 4 Activity decreasing Johnston (1997a)

1945 September 5 Explosive activity 4 Ash columns Johnston (1997a)

Hawke’s Bay Herald-Tribune 5.9.45

1945 September 7 Explosive activity 4 Ash columns, glow in column Johnston (1997a)

Letter to Dir. NZGS

1945 September 9 Larger single vent forming, strong 5 Columns to 20000 ft, blocks over 1000 ft Beck (1950) explosions Johnston (1997a)

GNS Science Report 2013/45 91

Date Description of Events Activity Comment Reference Scale

1945 September 10 Explosive activity 4 Activity continues Johnston (1997a)

1945 September 11 Explosive activity 4 Activity continues Johnston (1997a)

1945 September 13 Explosive activity 4 Activity continues Johnston (1997a)

1945 September 16 Explosive activity 4 Activity continues Johnston (1997a)

1945 September 17 Explosive activity 4 Activity continues Johnston (1997a)

Ashfall Chateau Wanganui Herald 17.9.1945

1945 September 20 Explosive activity 4 Activity continues Johnston (1997a)

1945 September 21 Explosive activity 4 Activity continues, blocks to 500 ft Johnston (1997a)

1945 September 27 Explosive activity 4 Activity continues, ash columns 9000 ft Johnston (1997a)

1945 September 28 Explosive activity 5 Activity continues, ash columns 12000 ft, Johnston (1997a) building shaken by airwaves Ashfall Ohakune Wanganui Herald 28.9.1945

1945 September 29 Explosive activity 4 Activity continues Johnston (1997a)

Ashfall Ohakune

1945 September 30 Explosive activity 5 Activity continues, ash columns 20-30000 ft Johnston (1997a)

Ashfall Chateau, Ohakune Letter to Dir. NZGS

Wanganui Herald 2.10.1945

1945 October 1 Explosive activity 5 Activity continues stronger Johnston (1997a)

Ashfall Chateau, Taupo NZ Herald 2.10.1945

1945 October 3 Explosive activity 5 Activity continues stronger, ash columns to Johnston (1997a) 30000 ft

1945 October 5 Ashfall in Whakatane 5 Johnston (1997a)

1945 October 6 Explosive activity 5 Activity continues, buildings shaken by Johnston (1997a) airwaves Ashfall in Taupo, Whakatane, Opotiki NZ Herald 8.10.1945

1945 October 7 Explosive activity 5 Activity continues, lightning in ash columns Johnston (1997a)

Ashfall in Whakatane

1945 October 8 Explosive activity 5 Activity continues Johnston (1997a)

1945 October 9 Explosive activity 5 Activity continues, blocks landing on Johnston (1997a) Whakapapa Glacier Ashfall in Rotorua, Taupo NZ Herald 9.10.1945

Dominion 10.10.1945

1945 October 10 Explosive activity 5 Stronger activity continues Johnston (1997a)

Ashfall Taupo, Hawke’s Bay Daily Telegraph 10.10.1945

1945 October 11 Explosive activity 5 Stronger activity continues Johnston (1997a)

1945 October 12 Explosive activity 5 Stronger activity continues Johnston (1997a)

1945 October 14 Explosive activity 4 Activity continues, blocks to 2-300 ft, ash Johnston (1997a) columns to 7000 ft Ashfall Hawke’s Bay Dominion 14.10.1945

1945 October 15 Explosive activity 4 Activity declines Johnston (1997a)

Ashfall Chateau

1945 October 16 Explosive activity 4 Activity declines, less ashfall Johnston (1997a)

1945 October 17 Explosive activity 4 Activity continues, ash laden steam Johnston (1997a)

1945 October 19 Ashfall Chateau 4 Wanganui Herald 22.10.1945

1945 October 20 Explosive activity 4 Activity continues, explosive ash columns Johnston (1997a)

Ashfall Chateau Wanganui Herald 22.10.1945

GNS Science Report 2013/45 92

Date Description of Events Activity Comment Reference Scale

1945 October 21 Explosive activity 4 Activity continues strong events Johnston (1997a)

Ashfall Chateau

1945 October 23 Explosive activity 4 Activity continues strong explosions Johnston (1997a)

1945 October 24 Explosive activity 4 Activity continues, explosions rattle windows Johnston (1997a)

Ashfall Taupo NZ Herald 25.10.1945

1945 October 29 Ashfall Hawke’s Bay 4 Daily Telegraph 31.10.1945

1945 October 30 Ashfall Hawke’s Bay 4 Daily Telegraph 31.10.1945

1945 November 2 Explosive activity 4 Activity declined, ashfalls continue Johnston (1997a)

Ashfall Hawke’s Bay

1945 November 3 Explosive activity 4 Activity declined, ashfalls continue Johnston (1997a)

Ashfall Hawke’s Bay

1945 November 4 Explosive activity 4 Activity declined explosions Johnston (1997a)

1945 November 5 Explosive activity 4 Activity declined, vents larger Johnston (1997a)

1945 November 6 Explosive activity 4 Activity declined, incandescence Johnston (1997a)

1945 November 7 Explosive activity 4 Activity increased Johnston (1997a)

1945 November 10 Ashfall Hawke’s Bay 4 Daily Telegraph 10.11.1945

1945 November 12 Explosive activity 4 Explosions heard in Taupo Johnston (1997a)

Ashfall Waiouru, Hawke’s Bay Dominion 14.11.1945

1945 November 13 Explosive activity 4 Explosions, incandescence Johnston (1997a)

Ashfall Waiouru, Hawke’s Bay Dominion 14.11.1945

1945 November 15 Explosive activity 4 Explosions, incandescence Johnston (1997a)

1945 November 16 Explosive activity 4 Activity continues Johnston (1997a)

1945 November 18 Explosive activity 4 Explosions, ash columns Johnston (1997a)

1945 November 20 Explosive activity 4 Explosions ashfalls Johnston (1997a)

Ashfall in Opotiki, Hawke’s Bay

1945 November 21 Explosive activity 4 Explosions ashfalls Johnston (1997a)

1945 November 23 Explosive activity 4 Explosions ashfalls Johnston (1997a)

1945 November 24 Explosive activity 4 Explosions ashfalls Johnston (1997a)

1945 December 1 Explosive activity 4 Explosions ashfalls Johnston (1997a)

Ashfall Hawke’s Bay Daily Telegraph 1.12.1945

1945 December 3 Ashfall Hawke’s Bay 4 Daily Telegraph 3.12.1945

1945 December 6 Weaker explosive activity 3 Weaker activity, less ashfalls Johnston (1997a)

Ashfall Hawke’s Bay Hawke’s Bay Herald Trib. 6.12.1945

1945 December 10 Weaker explosive activity 3 Weaker activity, less ashfalls Johnston (1997a)

1945 December 18 Weaker explosive activity 3 Weaker activity, less ash, reports of ‘spring’ Johnston (1997a) in crater

1945 December 21 Weaker explosive activity 3 Weaker activity, less ash Johnston (1997a)

1945 December 22 Weaker explosive activity 3 Weaker activity, less ash Johnston (1997a)

1945 December 23 Weaker explosive activity 3 Weaker activity, less ash Johnston (1997a)

1945 December 24 Weaker explosive activity 3 Weaker activity, less ash Johnston (1997a)

GNS Science Report 2013/45 93

Date Description of Events Activity Comment Reference Scale

1945 December 31 Weaker activity 3 Weaker activity, indications of a lakelet Johnston (1997a)

RUA 47/01

1946 January 4-26 Lake forming Observations confirm a lake is reforming Healy RUA 47/01

Johnston (1997a)

1946 February 14 Bright yellow-green lakelet Observations of the lakelet Healy RUA 47/01

1946 April 17 Ash eruption(s) 3 Snow discoloured by ashfall Taranaki Daily 18.4.1946

Wanganui Herald 18.4.1946

Latter (1985)

1946 May 31 Small explosion through lakelet 2 Observation from Healy RUA 47/01

1946 June Ash eruption(s) 2 Newspapers suggest mild activity during last Manawatu Daily 15.6.1946 two months producing ash and ashfall

1946 July 6 Weak geysering in new lake 2 Observation from Healy RUA 47/01

1946 September Steam emissions 0 Newspaper account, first fine weather for a Taranaki Daily News 4.9.1946 month

1946 October Crater steaming 0 Newspaper accounts, first fine weather for a Wanganui Herald 2.10.1946 month or so Wanganui Chronicle 2.10.1946 Classed as an eruption by Latter Taranaki Daily News 5.10.1946

Latter (1985)

1946 November Crater steaming 0 Newspaper account, clear weather Evening Post 21.11.1946

1947 January 24 Crater lake growing Observation from Healy RUA 47/01

1947 February 17 Steam eruption 3 Discoloured snow observed NZ Herald 19.2.1947

Latter (1985)

1947 March 15 Ash eruption 4 Ash and steam columns 5-7000 ft Evening Post 17.3.1947

NZ Herald 17.3.1947

1947 March 16 Ash eruption 4 Ash and steam columns 5-7000 ft Evening Post 17.3.1947

NZ Herald 17.3.1947

1947 April 27 Ash eruption(s) 4 Steam and ash columns c. 10,000 ft Dominion 30.4.1946

1947 April 28 Ash eruption(s) 4 Steam and ash columns c. 10,000 ft Dominion 30.4.1946

1947 May 31 Ash eruption (s) 5 Steam and ash columns 1500-12,000 ft, Taranaki Herald 2.6.1947 ashfall

1948 January 23 Steam column 4 Steam column 4-5000 ft NZ Herald 24.1.1948

Latter (1985)

1948 February 6 Steam columns 4 Several columns seen, to less than 3000 ft NZ Herald 9.2.1948

1948 February 7 Steam columns 4 Several columns seen, to less than 3000 ft NZ Herald 9.2.1948

1948 February 8 Steam columns 4 Several columns seen, to less than 3000 ft NZ Herald 9.2.1948

1948 February 10 Steam columns 3 Several columns seen, reports from Taupo NZ Herald 11.2.1948

1948 May 1 Explosive eruption 4 Photo and comments in Allen 1948 Allen (1948)

Latter (1985)

1949 May 1 Crater Lake steaming 0 Listed by Latter Gregg et al. (1960)

Newspaper comment Latter (1985)

Evening Post 18.5.1949

1949 September Crater Lake steaming 0 Newspaper comment Gregg et al. (1960)

Latter (1985)

NZ Herald 13.9.1949

GNS Science Report 2013/45 94

Date Description of Events Activity Comment Reference Scale

1950 June 19 Crater Lake steaming 0 Newspaper comment Gregg et al. (1960)

Dominion 21.6.1950

1950 June 24/25 Eruption from lake 3 Northern side black with ash on the snow, Gregg et al. (1960) reports from climbers NZ Herald 26.6.1950 Latter lists date as 26 June Latter (1985)

1951 March 19 Steam eruption from lake 3 Similar to June 1950 Healy (1956)

Latter (1985)

Evening Post 19.3.1951

1952 July Steam eruption 2 Phreatic eruption observed by climbers Thompson (1954)

Latter (1985)

1953 December 24 Break out flood, no eruption DB Tangiwai disaster

1954 October 7 Steam columns observed 1 Reports of surging and steam columns Christchurch Star Times 7.10.1954

1954 October 8 Steam columns 1 Reports of surging and steam columns Rotorua Post 8.10.1954

1954 October 11 Steam columns 1 Reports of surging and steam columns The Press 11.10.1954

1954 October 13 Steam columns 1 Reports of surging and steam columns NZ Herald 13.10.1954

1956 October 23 Steam columns observed 1 Newspaper report from climbs NZ Herald 23.10.1956

1956 November 18 Small phreatic/phreatomagmatic 3 Blackened snow about the lake, no evidence NZ Herald 20.11.1956 eruption noted by EF Lloyd in December Latter (1985)

1958 January 29 Small phreatic event observed 2 Green eruption from Crater Lake Blyth Hut visitor book

1959 May 21 Small phreatic/phreatomagmatic 3 Steam columns and minor ash The Daily Post 21.5.1959 eruption NZ Herald 22.5.1959

Latter (1985)

1959 June 2 Small phreatic/phreatomagmatic 3 Steam columns and minor ash NZ Herald 3.6.1959 eruption The Daily Post 3.6.1959

RUA 59/04

1959 June 9 Steam eruption 3 Steam columns and minor ash NZ Herald 10.6.1959

1959 July Steam eruption with some ash (?) 3 Possible report of ash RUA 59/04

1959 August 23 Steam eruption 3 Steam column observed from Orakeikorako RUA 59/04 (EFL)

1964 April 20-22? Report of high water levels in 3 Local farmer reports water level rises of 7 NZ Herald 28.5.1964 Wangaehu River feet, about six weeks before May 31. 1964 May 10-12 Latter (1985) Seismic activity started at same time.

1964 May 19 Crater Lake steaming 1 Steam columns and volcanic tremor RUA 64/01 recorded. Temperature increased to 50°C. Press 19.5.1964

1964 June 1 Crater Lake steaming 1 Steam column to 3000 ft NZ Herald .6.1964

1964 June 2 Crater Lake steaming 1 Steam columns NZ Herald 2.6.1964

1964 June 19 Crater Lake steaming 1 Steam columns over 3000 ft NZ Herald 29.6.1964

1966 March 22 Steam column observed 1 Lake was heating in March, steam reported RUA 66/09 often NZ Herald 22.3.1966

1966 April 4 Steam eruption 2 Event inferred as pH in Whangaehu had RUA 66/09 dropped

1966 July 24 Small phreatomagmatic eruption 2 Some mud about shore, expanded lava RUA 66/02 fragments Latter (1985) Later has date as 23 July

GNS Science Report 2013/45 95

Date Description of Events Activity Comment Reference Scale

1966 August 2 Small phreatomagmatic eruption 2 Fresh pumice bombs RUA 66/03

RUA 66/04

1966 August 11 Small phreatomagmatic eruption(s) 2 Confined to basin, two eruptions observed RUA 66/04

1966 August 19 Small phreatomagmatic eruption(s) 2 Four eruptions observed, muddy water RUA 66/05 ejected

1966 August 22 Small phreatic eruption 2 Geyser like eruptions RUA 66/07

1966 September 27 Small geyser-like events in lake 2 Two events observed, confined to lake RUA 66/10

1966 September 29 Small geyser-like event 1 Small event observed RUA 70/11

1966 October 18 Small geyser-like event 1 Small event observed RUA 66/11

1966 October 24 Steam columns observed 1 Sketches of steam columns RUA 66/12

1967 July 22-30 Small geyser-like eruptions 1 Geyser-like events observed, lake edge RUA 76/06 snow cut back

1967 September 4 Steam eruption 1 Steam column observed Letter to J Healy

1968 April 6-7 Geyser-like eruptions in lake 1 Numerous events observed, water doming RUA 68/03 to 15 m, black jets to 30 m RUA 70/11

Latter 1985

1968 April 15 Steam column Mushroom shaped cloud reported 2330h RUA 70/11

1968 April 20 Ash on snow, small lahars 2-3 Photos of ash deposit and snow lahars RUA 68/05

1968 April 26 Moderate phreatomagmatic eruption 3 Mud and ash on snow and lahar in RUA 68/06-07 with lahar down Whangaehu valley Whangaehu valley

1968 April 27 Small eruptions, minor lahar 3 Ash eruptions, small lahar RUA 68/08

RUA 68/13

1968 May 7-June 3 Several small phreatic or 3-4 Confined to basin, eroded lake shore RUA 68/14 phreatomagmatic eruptions Ashfall observed at Moawhango Dam 31 RUA 68/15 May 1968 RUA 70/11

1968 June 4 Small eruption 3 Mud and steam RUA 70/04a

1968 June 8 Small eruption (2100h) 4 Ash 2-3 cm thick and rocks Pare to Pyramid RUA 68/18 area

1968 October 7 Possible activity 2 Discoloured snow reported from 7 October, RUA 68/31 very weak evidence of activity

1969 June 22 Major phreatomagmatic eruption 5 Lahars down Whakapapanui, Whakapapa, Healy et al. (1978) Mangaturuturu and Whangaehu valleys, Latter (1985) ashfall to 25 km

1970 September 16 Small phreatic/phreatomagmatic 2 Confined to basin RUA 70/07 eruption

1971 April 3 Small phreatic/phreatomagmatic 3 Surge marks 10 m above lake, evidence of RUA 71/05 eruption lahar in Whangaehu, possible ash

1971 April 21 Small phreatic eruption 2 Based on seismic data (1629h) RUA 71/07

1971 April 22 Small phreatic eruption 3 Based on seismic data (0027h), mud on RUA 71/07 Pyramid Peak

1971 May 8 Moderate phreatomagmatic eruption 3 Two small phreatic events in the hour before RUA 71/09 (1555h) with lahar down Whangaehu Latter (1985) valley

1971 May 16 Numerous moderate eruptions with 4 Affected summit plateau, Mangaturuturu and RUA 71/12 lahars down Whangaehu valley, and Whangaehu valleys RUA 71/13 mud flow into the Mangaturuturu valley

GNS Science Report 2013/45 96

Date Description of Events Activity Comment Reference Scale

1971 May 17 Small phreatic/phreatomagmatic 3 Water mud ejected 100-130 m above lake RUA 71/14 eruption

1971 May 19 Small phreatic events 2 Paterson reports minor lahar Paterson (1976)

1971 May 21 Small phreatic events observed 1 Muddy water geysering 3-4 m RUA 71/16

1971 May 22 Small phreatic/phreatomagmatic 3 Observed by J Healy, base surges, eruption RUA 71/17 eruption 300-450 m

1971 May 26 Small phreatic events 1 Geysering to about 10 m RUA 71/18

1971 June 8 Small phreatic event 2 Observed from Chateau RUA 71/19

1971 June 9 Small phreatic event 1 Geysering to 30 m RUA 71/19

1971 June 18 Small phreatic events 2 Four events observed, 10-20 m high, surges RUA 71/20 through outlet

1971 July 3 Small phreatic events 2 Surging through the outlet Paterson (1976)

1971 July 4 Small phreatic events 2 Surging through the outlet Paterson (1976)

1971 July 6-14 Ash on snow, small event (s) 3 Muds lay on new snow (last snow 5 July) RUA 71/21

1971 July 14 Small phreatic/phreatomagmatic 3 Confined to summit plateau and Whangaehu RUA 71/21 eruption with surges down Whangaehu valley valley

1971 July 20 Small events 2 Small geysering events heard, waves RUA 71/22

1971 August 20 Phreatic events 2 Small geysering events, waves (three RUA 71/23 observed in 2.5 hours)

1971 August 23 Small phreatic events 2 Small geysering events, jets to 30-35 m (six RUA 71/24 observed)

1971 August 24 Small phreatic events 2 Small events heard RUA 71/25

1971 August 27 Small phreatic events 2 Small events heard/seen RUA 71/25

1971 September 15 Small phreatic events 2 5 small events observed, 15 m RUA 71/26

1971 September 16 Small phreatic events 2 Several observed RUA 71/26

1971 September 17 Small phreatic events 2 Small events reported RUA 71/28

1971 October 14 Small phreatic events 2 Small events reported by climbers RUA 71/28

1971 October 15 Small phreatic events 2 Two observed, 10-15 m RUA 71/27

1971 October 16 Small phreatic events 2 Two observed RUA 71/28

1971 October 24-30? Moderate/large phreatic eruption(s) 3 Muds found to 60 m above lake. Date RUA 71/29 deduced from snow record.

1971 November 1 Small phreatic events 2 Three geyser-like eruptions in lake RUA 71/29

1972 October 22 Small phreatic events 2 Domed water 5-10 m, geysering (3 events RUA 72/10 seen)

1972 November 21 Small event 2 Only based on seismics RUA 72/11a

1973 January 7 Small phreatic eruption in lake 1 Confined to lake, report via TNP RUA 73/01

1973 October 31 Small phreatic eruptions in lake 1 Confined to lake, doming 10-15 m RUA 73/09

1973 November 23 Small phreatic eruptions in lake 2 Geysering to 20 m, waves RUA 73/11

1973 November 28 Possible small phreatic event 1 Steam columns observed from Taupo RUA 73/12

1974 January 15 Small phreatic event 1 Lake domes 3-5 m RUA 74/01

1974 January 27 Small phreatic event 1 Observed by helo pilot RUA 74/02

1974 March 9 Small phreatic event 1 Observed from Dome RUA 74/03

GNS Science Report 2013/45 97

Date Description of Events Activity Comment Reference Scale

1974 March 11 Small phreatic eruptions 1 Three observed in 10 hours RUA 74/05

1974 March 12 Phreatic eruption 1 Confined to lake, observed during an RUA 74/04 inspection

1974 March 13 Phreatic eruptions 2 Largest jetted to 30-40 m, three observed in RUA 74/05 four hours

1974 March 22 Possible phreatic activity 1 Steaming pools observed in outlet, steam RUA 74/06 columns

1974 March 29 Possible phreatic activity 2 Surge marks measured in outlet RUA 74/07

1974 March 30 Phreatic eruption 1 Doming observed to 20 m RUA 74/07

1974 April 11 Phreatic eruption 1 Doming observed in lake, jetting RUA 74/08

1974 May 12 Phreatic eruptions 1 Two eruptions observed, jetting/doming to RUA 74/09 17 m

1974 August 2 Larger phreatic eruption, ash 3 Discoloured ash up to 1 km from lake RUA 74/12

1974 August 6 Small phreatic event 2 Deposits in snow pack RUA 74/12

1974 August 9 Small phreatic eruptions 1 Four observed RUA 74/12

1974 October 25 Small phreatic event 1 3 m doming in lake RUA 74/14

1975 April 24 Major phreatomagmatic eruption. 5 Risk to life on summit plateau and in all RUA 75/06 Lahars down Whakapapanui, major valleys; ash to a 130 km from vent Nairn et al. (1979) Whakapapaiti, Mangaturuturu and Whangaehu valleys Latter (1985)

1975 April 27 Moderate phreatomagmatic eruption 4 Confined to summit plateau and upper RUA 75/04 Whangaehu valley, lahars RUA 75/05

1975 October 4 or 17 Moderate phreatic (phreatomagmatic?) 3 Evidence of wave action and ash in snow RUA 75/10 eruption (date uncertain)

1976 March 6 Small phreatic event 1 Observed by ranger RUA 76/05

1976 May 5 Possible small events (?) 2 Evidence of higher lake levels RUA 76/07

1976 September 10 (?) Possible eruption (s) 2 Evidence of ash and snow cut back RUA 76/11

Latter has date of 12 September Latter (1985)

1976 November (?) early Possible eruption (s) 2 Evidence of ash and snow cut back RUA 76/12

1976 November 23 Evidence of activity 2 Snow stripped back up to 3 m above water RUA 76/13 level

1977 July pre 5th Evidence of activity 2 Evidence of surge thru outlet RUA 77/06

1977 July 12 Small phreatic eruption 2 Steam columns, discoloured snow to 30 m RUA 77/07 above lake Latter (1985)

1977 August 12 Small phreatic event 1 Steam column observed RUA 77/08

1977 October 1-16 (?) Moderate phreatic event 2 Ash observed on snow (Pyramid), date RUA 77/09 unknown

1977 October 19 Small phreatic event 1 Observed doming in lake RUA 77/10

1977 November 2 Moderate phreatomagmatic eruption 4 Ballistics 700 m from the lake, ash apron RUA 77/11 with lahar down Whangaehu valley extending NE over 5 km, rare breadcrust RUA 77/12 bombs Latter (1985)

1977 November 4 Small phreatomagmatic eruption 2 Possible ash on snow, steam columns RUA 77/12 observed

1977 November 7 Small phreatomagmatic eruption 1 Steam column observed RUA 77/12

GNS Science Report 2013/45 98

Date Description of Events Activity Comment Reference Scale

1977 November 9 Small phreatomagmatic eruption 1 Steam column observed RUA 77/12

1978 January 18 Very small phreatic eruption 1 Confined to lake, upwelling RUA 78/01

1978 March 7 Moderate phreatic eruption 4 Ash on snow 2 km down wind from vent RUA 78/04

Latter (1985)

1978 June 12 Small phreatic eruption 1 Rapid upwelling RUA 78/08

1978 June 13 Small phreatic eruptions 1 Six small events observed RUA 78/08

1978 June 15 Small phreatic eruptions 1 Six small events observed RUA 78/08

1978 June 16 small phreatic eruptions 1 Two small events observed RUA 78/08

1978 September 2 Phreatic activity 2 Ash observed on snow RUA 78/12

1978 September 7 Phreatic activity 2 Ash on snow, eruption observed by skier RUA 78/12

1978 September 9 Phreatic activity 1 Report from park rangers of observed RUA 78/12 activity

1978 October 30-31 Phreatic activity 2 Possible ash on snow RUA 78/14

1979 January 17 Moderate phreatomagmatic eruption 2 Confined to lake, jetting to 200 m RUA 79/02

1979 June 30 Phreatic activity 2 Hut log, two eruptions observed, doming to RUA 79/07 5 m

1979 July 15 Phreatic activity 1 Steam column reported RUA 79/06

1979 August 18 Phreatic activity 1 Steams column observed RUA 79/07

1979 December 10-24 Small phreatic/phreatomagmatic 3 Ash seen on snow from 35 km away, also RUA 80/01 eruption climber report of ash on Pyramid peak. Date uncertain.

1980 January 29 Phreatic/phreatomagmatic eruption 1 Confined to lake, jets to 10 m RUA 80/02

1980 February 2 Small phreatic/phreatomagmatic 1 Confined to lake, climbers report sounds and RUA 80/03 eruption steam

1980 February 6 Small phreatic/phreatomagmatic 1 Steam column observed RUA 80/03 eruption

1980 February 20 Small phreatic eruptions 1 Four observed, doming to 5 m RUA 80/04

1980 February 29 Small phreatic/phreatomagmatic 1 Four observed, doming 5-10 m RUA 80/05 eruptions

1980 March 27 small phreatic/phreatomagmatic 1 Three observed, doming/jets to 20 m RUA 80/07 eruptions

1980 April 12 small phreatic/phreatomagmatic 1 Four observed, jets to 30 m RUA 80/08 eruptions

1980 April 13 small phreatic/phreatomagmatic 1 Two events, jets to 30 m RUA 80/08 eruption

1980 April 14 small phreatic/phreatomagmatic 1 Large steam plume observed RUA 80/08 eruption

1980 April 16 small phreatic/phreatomagmatic 1 Steam plume observed RUA 80/08 eruption

1980 October 18 Very small phreatic/phreatomagmatic 2 Confined to basin, ash in snow, volcanic RUA 80/17 eruption earthquake

1980 November 3 Very small phreatic/phreatomagmatic 2 Ash in snow, volcanic earthquake RUA 80/18 eruption

1981 October 10-November 1 Very small phreatic/phreatomagmatic 2 Ash in snow (date unknown) RUA 81/11 eruption

GNS Science Report 2013/45 99

Date Description of Events Activity Comment Reference Scale

1981 November 19 Very small phreatic/phreatomagmatic 3 Ash in snow, flood peak RUA 81/12 event

1981 November 24 Small phreatic/phreatomagmatic 1 Two events observed RUA 81/12 eruption

1981 December 18 Phreatic/phreatomagmatic eruption (s) 1 Two events observed, jets to 100 m. Other RUA 81/13 steam plumes also seen.

1982 January 10 Phreatic/phreatomagmatic eruption (s) 1 Eruption observed by float plane operator RUA 81/13a

1982 January 11 Phreatic/phreatomagmatic eruption (s) 1 Observed from Ohakea RUA 82/01

1982 January 12 Phreatic/phreatomagmatic eruptions 1 23 eruptions observed, jets up to 40 m RUA 82/01

1982 January 18 Phreatic/phreatomagmatic eruptions 1 Four eruptions observed, jets to 50 m RUA 82/01

1982 January 22 Phreatic/phreatomagmatic eruptions 1 20 eruptions observed, jets to 50 m RUA 82/01

1982 February 5 Phreatic/phreatomagmatic eruptions 1 Three eruptions RUA 82/02

1982 February 11 Phreatic/phreatomagmatic eruptions 1 Five eruptions observed RUA 82/03

1982 February 12 Phreatic/phreatomagmatic eruptions 1 Two eruptions observed RUA 82/03a

1982 March 6 Phreatic/phreatomagmatic eruptions 1 Two eruptions observed RUA 82/04

1982 March 16 Phreatic/phreatomagmatic eruption 1 Steam column reported RUA 82/06

1982 March 18 Phreatic/phreatomagmatic eruption 1 An eruption was observed, waves 1 m in RUA 82/05 outlet

1982 March 23 Phreatic/phreatomagmatic eruption (s) 1 Five observed, jets from 20-100 m RUA 82/06

1982 March 26 Phreatic/phreatomagmatic eruption 1 Jetting RUA 82/06

1985 May 21 Phreatic eruption 1 Hydrothermal eruptions reported RUA 85/05

1985 May 25 Phreatic eruption (s) 1 Eruptions observed, to 10 m RUA 85/05

1985 May 28 Phreatic eruptions 1 15 eruptions observed, jets to 10 m RUA 85/05

1985 June 4 Phreatic eruptions 1 10 eruptions observed, jets 10-15 m RUA 85/06

1985 October 31 Phreatic eruption 2 Upwelling, surging observed RUA 85/12

1985 November 11 Phreatic eruption 1 Upwelling and steam observed RUA 85/12

1985 November 15 Small phreatic eruption 1 Small upwellings observed (two occasions) RUA 85/12

1986 February 8 Very small phreatic eruptions 1 Steam and sounds twice RUA 86/02

1986 February 9 Very small phreatic eruption 1 Seen from flight RUA 86/02

1987 August 24 Very small phreatic eruptions 1 Confined to lake 1 m doming RUA 87/07

1987 August 29 Small phreatic event (s) 1 Steam observed from Taupo RUA 87/07

1987 August 30 Small phreatic event (s) 1 Steam observed from Taupo RUA 87/07

1987 August 31 Small phreatic event (s) 1 Muds observed to 10 m RUA 87/07

1988 March 20 Small phreatic events 1 Noises heard, lake disturbed RUA 88/03

1988 March 22 Small phreatic event 1 Activity seen in lake RUA 88/03

1988 March 26 Small phreatic event 1 Activity seen in lake RUA 88/03

RUA 88/04

1988 April 12 Small phreatic event 1 Activity seen in lake RUA 88/04

1988 April 16 Small phreatic event 1 Activity seen in lake RUA 88/05

1988 April 19 Small phreatic event 1 Steam column RUA 88/05

GNS Science Report 2013/45 100

Date Description of Events Activity Comment Reference Scale

1988 December 8 Moderate phreatic eruption with small 4 Summit plateau and Whangaehu valley; ash RUA 88/12 lahar down Whangaehu valley 1.1 km NE of vent

1989 January 27 Small phreatic eruption 1 Steaming and lake doming RUA 89/02

1989 January 28 Small phreatic eruption 1 Steam observed RUA 89/02

1989 January 29 Small phreatic eruption 1 Jetting observed RUA 89/02

1989 January 31 Small phreatic eruption 1 Steam observed RUA 89/02

1989 February 6 Small phreatic eruption 1 Steam observed RUA 89/03

1989 February 15 Small phreatic eruption 1 Steam observed RUA 89/04

1989 February 27 Small phreatic eruption 1 Steam observed RUA 89/04

1989 February 28 Small phreatic eruption 1 Steam observed RUA 89/04

1989 July 1 Small phreatic eruption 1 Lake disturbances observed RUA 89/08

1989 July 2 Small phreatic eruption 1 Small eruption observed RUA 89/08

1989 July 3 Small phreatic eruption 1 Two steam columns observed RUA 89/08

1989 July 24 Small phreatic eruption 1 Eruption observed at outlet RUA 89/08

1990 January 7 Small phreatic eruption 1 Jetting observed 50-60 m RUA 90/01

1990 January 12 Small phreatic eruptions 1 Jetting to 20 m RUA 90/01

1990 January 14 Small phreatic eruptions 1 Eruptions reported as small and large RUA 90/01

1990 January 23 Small phreatic eruption 1 Pilot observation RUA 90/02

1990 January 24 Small phreatic eruption 1 Steam column observed RUA 90/02

1990 January 25 Small phreatic eruption 1 Steam column observed RUA 90/02

1990 January 26 Small phreatic eruptions 1 Five small eruptions seen, 1-5 m high, RUA 90/02 steam columns

1990 January 31 Small phreatic eruptions 1 Two events, lake up doming seen RUA 90/02

1990 February 1 Small phreatic eruption 1 Eruption observed, doming 10 m RUA 90/03

1990 February 4 Small phreatic eruptions 1 Three events observed RUA 90/03a

1990 June 17 Floating blocks 1 Two events bringing floating blocks to lake RUA 90/07 surface

1992 February 8 Minor phreatic eruption 1 Upwelling in lake RUA 92/02

1992 February 12 Minor phreatic activity 1 Steam columns observed RUA 92/03

1992 February 18 Small phreatic eruption(s) 1 Observed on two scenic flights, waves 1 m RUA 92/02

RUA 92/03

1992 February 20 Small phreatic eruption 1 Climber report RUA 92/03

1992 February 23 Small phreatic eruption 1 Climber report RUA 92/03

1992 March 6 Small phreatic eruption 1 Climber and pilot reports RUA 92/03

1994 February 12 Small phreatic eruption 1 Climber report RUA 94/02

1994 March 1 Small phreatic eruption 1 Observed from Dome RUA 94/02

1994 March 5 Small phreatic eruption 1 Observed from Dome RUA 94/02

1994 March 7 Small phreatic eruption 1 Observed from Dome, upwelling RUA 94/02

1994 March 31 Small phreatic eruption 1 Steam columns observed RUA 94/02

1995 January 14 Phreatic eruptions 1 Three events observed, jetting to 60 m RUA 95/01

GNS Science Report 2013/45 101

Date Description of Events Activity Comment Reference Scale

1995 January 20 Small phreatic eruption 1 Lake being disturbed RUA 95/01

1995 January 24 Small phreatic eruption 1 Lake being disturbed RUA 95/02

1995 January 29 Small phreatic eruptions 1 Two minor eruptions observed RUA 95/02

1995 January 30 Small phreatic eruption 1 Eruption observed, 10-20 m high RUA 95/02

1995 February 5 Small phreatic eruptions 1 Two minor eruptions heard RUA 95/02

1995 February 15 Small phreatic eruption(s) 1 Steam columns observed RUA 95/02

1995 February 25 Small phreatic eruption 1 Steam column observed RUA 95/02

1995 February 27 Small phreatic eruption 1 Pilot report, activity to 30 m RUA 95/02

1995 April 25 Activity in lake 1 Rapid changes recorded by ARGOS RUA 95/03 equipment

1995 April 27 Phreatic eruptions 1 Three small eruptions observed in lake RUA 95/03

1995 May 7 Phreatic eruptions 1 Two eruptions observed and reported RUA 95/03

1995 May 25 Phreatic/phreatomagmatic eruption 1 Lake disturbance observed RUA 95/04

1995 June 29 Phreatic/phreatomagmatic eruption 3 Destroyed ARGOS equipment, minor ash in RUA 95/04 snow out +100 m

1995 July 4 Phreatic/phreatomagmatic eruption 2 Two eruptions observed RUA 95/04

1995 September 18 Moderate phreatomagmatic eruption 4 Summit plateau and Whangaehu valley RUA 95/06 with lahar down Whangaehu valley

1995 September 20 Phreatic/phreatomagmatic eruptions, 2 Twenty events observed in the lake, large RUA 95/06 large overflow into Whangaehu >1000 overflow l/s

1995 September 23 Major phreatomagmatic eruption 5 Lahars down Whakapapanui, Mangaturuturu Bryan and Sherburn (1999) and Whangaehu valleys; ash 150 km from Nairn et al. (1998) vent

1995 September 24 Smaller surtseyan type eruptions with 2 Bryan and Sherburn (1999) possible lahars down Whangaehu valley Nairn et al. (1998)

1995 September 25 Smaller surtseyan type eruptions with 4 Summit plateau and Whangaehu valley; ash Bryan and Sherburn (1999) large lahars down Whangaehu valley 10 km E from vent Nairn et al. (1998)

1995 September 26 Smaller phreatomagmatic eruptions 4 Summit plateau affected Bryan and Sherburn (1999)

Nairn et al. (1998)

1995 September 27 Smaller phreatomagmatic eruptions 4 Summit plateau affected Bryan and Sherburn (1999)

Nairn et al. (1998)

1995 September 28 Smaller phreatomagmatic eruptions 4 Summit plateau affected Bryan and Sherburn (1999)

Nairn et al. (1998)

1995 September 29 Smaller phreatomagmatic eruptions 4 Summit plateau affected Bryan and Sherburn (1999)

Nairn et al. (1998)

1995 September 30 Smaller phreatomagmatic eruptions 4 Summit plateau affected Bryan and Sherburn (1999)

Nairn et al. (1998)

1995 October 1 Smaller phreatomagmatic eruptions 4 Summit plateau affected Bryan and Sherburn (1999)

Nairn et al. (1998)

1995 October 2 Smaller phreatomagmatic eruptions 4 Summit plateau affected Bryan and Sherburn (1999)

Nairn et al. (1998)

1995 October 3 Smaller phreatomagmatic eruptions 4 Summit plateau affected Bryan and Sherburn (1999)

Nairn et al. (1998)

GNS Science Report 2013/45 102

Date Description of Events Activity Comment Reference Scale

1995 October 4 Smaller phreatomagmatic eruptions 4 Summit plateau affected Bryan and Sherburn (1999)

Nairn et al. (1998)

1995 October 5 Smaller phreatomagmatic eruptions 4 Summit plateau affected Bryan and Sherburn (1999)

Nairn et al. (1998)

1995 October 7 Large phreatomagmatic eruption with 4 Summit plateau and Whangaehu valley Bryan and Sherburn (1999) lahar down Whangaehu valley Nairn et al. (1998)

1995 October 11 Near-continuous major magmatic 5 Major magmatic eruptions with voluminous Bryan and Sherburn (1999) eruptions with voluminous ash ash emissions, plume >10 km; ash 250 km Nairn et al. (1998) emissions NE of vent

Crater lake removed

1995 October 12 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions Nairn et al. (1998)

1995 October 13 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions Nairn et al. (1998)

1995 October 14 Major magmatic eruption with 5 Eruption with voluminous ash emissions >11 Bryan and Sherburn (1999) voluminous ash emissions and lahar km and snow melt lahar down Whangaehu Nairn et al. (1998) down Whangaehu valley valley; ash 200 km SE of vent

1995 October 15 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions Nairn et al. (1998)

1995 October 16 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions Nairn et al. (1998)

1995 October 17 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions Nairn et al. (1998)

1995 October 18 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions Nairn et al. (1998)

1995 October 19 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1995 October 20 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1995 October 21 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1995 October 22 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1995 October 23 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1995 October 24 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1995 October 25 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1995 October 26 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1995 October 27 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1995 October 28 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

GNS Science Report 2013/45 103

Date Description of Events Activity Comment Reference Scale

1995 October 29 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1995 October 30 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1995 October 31 Degassing-type eruptions and minor 3 Ash eruptions from two vents in the crater Bryan and Sherburn (1999) ash eruptions, decreasing in vigour Nairn et al. (1998)

1996 April 21 NE rim collapse on to Whangaehu Landslide onto glacier triggers lahar/flood Scott (2003) Glacier

1996 June 17 Major phreatomagmatic eruptions 5 Major phreatomagmatic and strombolian Scott (2003) followed by strombolian eruptions with eruptions, lahar in Whangaehu valley; ash Bryan and Sherburn (2003) lahar down Whangaehu valley reaching to Bay of Plenty coast

1996 June 18 Weak to moderate ash eruptions 3 Crater Lake removed, ash cone formed on Scott (2003) crater floor Bryan and Sherburn (2003)

1996 June 19 Weak to moderate ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 June 20 Weak to moderate ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 June 21 Weak ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 June 22 Weak ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 June 23 Weak ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 June 24 Weak ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 June 25 Weak ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 June 26 Weak ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 June 27 Large magmatic eruptions followed by 4 Eruption column reaches to 7 km. Scott (2003) ash eruptions Bryan and Sherburn (2003)

1996 June 28 Ash eruptions 3 Eruptions declining from previous day Scott (2003)

Bryan and Sherburn (2003)

1996 June 29 Minor ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 June 30 Minor ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 1 Minor ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 2 Minor ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 3 Minor ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 4 Large ash eruption 4 Summit plateau; ash 40 km downwind from Scott (2003) vent Bryan and Sherburn (2003)

GNS Science Report 2013/45 104

Date Description of Events Activity Comment Reference Scale

1996 July 5 Minor ash eruptions 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 6 Ash eruptions increasing 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 7 Ash eruptions increasing 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 8 Large near-continuous strombolian 4 Significant increase in activity and change in Scott (2003) eruptions style Bryan and Sherburn (2003)

1996 July 9 Stronger eruptions continue 4 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 10 Stronger eruptions continue 4 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 11 Stronger eruptions continue 4 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 12 Stronger eruptions continue 4 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 13 Stronger eruptions declining 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 14 Stronger eruptions declining 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 15 Ash eruptions to over 6-7000 m 5 Summit plateau and area surrounding Scott (2003) mountain Bryan and Sherburn (2003)

1996 July 16 Several large magmatic eruptions with 4 Summit plateau and area surrounding Scott (2003) large ash plumes mountain Bryan and Sherburn (2003)

1996 July 17 Weaker eruptions 3 Activity declining Scott (2003)

Bryan and Sherburn (2003)

1996 July 18 Weaker eruptions 3 Activity declining Scott (2003)

Bryan and Sherburn (2003)

1996 July 20 Large magmatic eruptions with large 5 Summit plateau and area surrounding Scott (2003) ash plumes and fire fountaining mountain; ash east of the vent. Plumes Bryan and Sherburn (2003) 6100-7500 m.

1996 July 21 Moderate-strong eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 22 Moderate-strong eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 23 Moderate-strong eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 24 Moderate-strong eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 25 Moderate-strong eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 26 Moderate-strong eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 27 Strong eruptions 5 Eruptions from vent on crater floor, plumes Scott (2003) to 9700 m Bryan and Sherburn (2003)

GNS Science Report 2013/45 105

Date Description of Events Activity Comment Reference Scale

1996 July 28 Moderate-strong eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 29 Weaker eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 30 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 July 31 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 August 1 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 August 2 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 August 3 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 August 4 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 August 5 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 August 6 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 August 7 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 August 8 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 August 9 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 August 14 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 August 19 Minor eruptions: variable 3 Eruptions from vent on crater floor, ash on Scott (2003) northern slopes Bryan and Sherburn (2003)

1996 September 1 Minor eruptions: variable 3 Eruptions from vent on crater floor, ash on Scott (2003) Turoa ski field Bryan and Sherburn (2003)

1996 September 2 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 September 3 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 September 4 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 September 5 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 September 6 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 September 7 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

GNS Science Report 2013/45 106

Date Description of Events Activity Comment Reference Scale

1996 September 8 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1996 September 9 Minor eruptions: variable 3 Eruptions from vent on crater floor Scott (2003)

Bryan and Sherburn (2003)

1997 October 2 Minor phreatic eruption 1 Eruption seen at 1615h Keys (1998a)

1997 October 9 Small phreatic eruptions 1 Small eruption 10-20 m high Keys (1998a)

1997 October 10 Phreatic eruptions 2 Sulphur and ash in Crater basin Keys (1998a)

1997 October 11 Phreatic activity 3 Steam burst to 1000 m, fine ash over Keys (1998a) Pyramid

1997 October 12 Minor phreatic eruptions 3 Ballistic material over crater rim Keys (1998a)

1997 October 18 Small phreatic eruption 3 Eruption and earthquake Keys (1998a)

1997 November 3 Minor phreatic eruptions 3 Ash and minor lahar Keys (1998a)

1997 November 4 Small eruptions 3 Ash and minor lahar, ballistics out to 400 m Keys (1998a)

1997 November 5 Small eruptions 3 Minor ash and ballistics Keys (1998a)

1997 November 6 Small eruptions 3 Minor ash and ballistics Keys (1998a)

1997 November 7 Small eruptions 3 Minor ash and ballistics Keys (1998a)

1998 January 1 Small phreatic eruptions 2 Minor ash Keys (1998b)

1998 January 2 Small phreatic eruptions 2 Minor ash Keys (1998b)

1998 November 8 Small phreatic eruptions 2 Minor ash Wilson (2009)

Keys (1999)

1999 17 September-16 Steam eruptions and gas burst? 1 Minor activity Keys (1999) October

2005 September 13 Steam seen above volcano 1 Possibly minor activity Keys (2006)

(Sherburn: Volcano News, 13 September 2005)

2006 October 4 Minor hydrothermal eruption 2 Confined to basin

2007 March 18 Flooding in Whangaehu Valley DB Dam Break event Keys (2007)

2007 September 25 Moderate hydrothermal eruptions with 4 Confined to summit plateau and Whangaehu lahars down Whangaehu valley and valley and Whakapapa ski field Whakapapa ski field

2009 July 13 Phreatic activity 2 Small snow slurry lahars in upper Whangaehu

GNS Science Report 2013/45 107

Principal Location Other Locations

1 Fairway Drive Dunedin Research Centre Wairakei Research Centre National Isotope Centre Avalon 764 Cumberland Street 114 Karetoto Road 30 Gracefield Road PO Box 30368 Private Bag 1930 Wairakei PO Box 31312 Lower Hutt Dunedin Private Bag 2000, Taupo Lower Hutt New Zealand New Zealand New Zealand New Zealand T +64-4-570 1444 T +64-3-477 4050 T +64-7-374 8211 T +64-4-570 1444 www.gns.cri.nz F +64-4-570 4600 F +64-3-477 5232 F +64-7-374 8199 F +64-4-570 4657