SOPAC

SOPAC /GA Tsunami Hazard Assessment Project Report 04 Inventory of Geospatial Data and Options for Tsunami Inundation & Risk Modelling SOLOMON ISLANDS

Helen Pearce (helen@a sopac.org)

January 2008 [2]

Complied by

Helen Pearce

Ocean & Islands Programme SOPAC Secretariat

This report may also be referred to as SOPAC Miscellaneous Report 654

Copies of this report may be obtained from: SOPAC Secretariat Private Mail Bag GPO, Suva Fiji Islands Phone: (679) 3381377 Fax: (679) 3370040 http: / /www.sopac.org E -mail: [email protected]

[SOPAC Miscellaneous Report 654 - Pearce] [3]

TABLE OF CONTENTS

ACKNOWLEDGEMENTS 4 ACRONYMS 4

1 INTRODUCTION 5 2 SOURCES OF TSUNAMI HAZARD 6 3 VULNERABILITY /EXPOSURE 8 4 OVERVIEW OF TSUNAMI HAZARD AFFECTING SW PACIFIC 10 (i) Summary Extracts. 10 (ii)Summary and Interpretation for Solomon Islands 14 (a) Composite of Deep -water Tsunami generated by 8.5 Mw Sources around Pacific 14 (b) Composite of Deep -water Tsunami generated by 9.0 Mw Sources around Pacific 15 5 Data Available at SOPAC for Inundation Modelling 16 (i) Bathymetry Datasets and Marine Charts 16 (ii) Satellite Imagery 26

NO Topography, Coastline and Reefs 26 (iv) Infrastructure data 27 (v) Post tsunami inundation /run -up data 27 (iv) Data Summary 30 6 SUMMARY 32 7 REFERENCES 33 APPENDIX 1: Datum and Definitions 35

1 Datum and Geodetic Levels at Honiara 35 2 Topographic Dataset Issues for PICs 36 3 Definitions and Acronyms 37 APPENDIX 2: Historical Tsunami Events Affecting Solomon Islands 44

1 Previous Tsunami that have been recorded in Solomon Islands 44 2 Recent PTWC Warnings 46 3 Tsunami Warning Related Background 59 (í) Summary of JMA /PTWC causal earthquake criteria 59 (ii) Tsunami hazard sources 60 (iii)Real -Time Sea level data available for Tsunami monitoring 61 Appendix 3: Additional Modelling 64

1 Modelling of major tsunami for sources around the Pacific 64 2 MOST scenarios for sources affecting Solomon Islands 70

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ACKNOWLEDGEMENTS

The assistance of Mary Power, Arthur Webb and Jens Kruger of SOPAC, Phil Cummins, Chris Thomas and Jane Sexton of Geoscience Australia, Ruth Broco of NGDC Tsunami Database and project funding from AusAid is gratefully acknowledged.

ACRONYMS (Also see Appendix 1 -3)

ABoM Australian Bureau of Meteorology ATAS Australian Tsunami Alert Service (superseded by JATWC) CD Chart Datum DART Deep -ocean Assessment and Reporting of Tsunami. DEM Digital Elevation Model DSM Digital Surface Model EEZ Economic Exclusion Zone GA Geoscience Australia GNS Geological and Nuclear Sciences, New Zealand GTS Global Telecommunications System HAT Highest Astronomical Tide IOC Intergovernmental Oceanographic Commission ITIC International Tsunami Information Centre JMA Japan Meteorological Agency JATWC Joint Australian Tsunami Warning Centre LIDAR Light Detection and Ranging LAT Lowest Astronomical Tide MOST Method of Splitting Tsunami ( type of numerical model) MSL Mean Sea Level NGDC National Geophysical Data Centre (NOAA) PIC Pacific Islands Countries PDC Pacific Disaster Centre PTWC Pacific Tsunami Warning Centre SOPAC Pacific Islands Applied Geoscience Commission SPSLMP South Pacific Sea Level and Climate Monitoring Project UNESCO United Nations Environmental, Scientific and Cultural Organisation UTC Universal Time Coordinate (also referred to by Z or GMT) UTM Universal Transverse Mercator WGS World Geodetic System WMO World Meteorological Organization

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1 INTRODUCTION

SOPAC and Geoscience Australia, funded by AusAid have established the first component of a multi -stage project to look at tsunami hazard and risk assessment in the Southwest Pacific. As part of that project Geoscience have produced a tsunami hazard assessment for the Southwest Pacific based on a deterministic deep -water tsunami propagation model (A Preliminary Study into the Tsunami Hazard faced by Southwest Pacific, Thomas et al. 2007). That report is available at via the Pacific Disaster Net ( http: / /www.pacificdisaster.net /drm /).In parallel with that component of the project a review of data available for inundation modelling in SW Pacific is being conducted by SOPAC, as inundation modelling requires significantly higher -resolution bathymetry, inter -tidal and coastal topography than the deep -water propagation models.

Deep -water models alone are not sufficient to develop a detailed understanding of tsunami inundation on coastlines and ultimately it is proposed that the deepwater model output will be used to define the boundary conditions to allow more detailed, site specific tsunami inundation modelling of key and priority PIC coastal areas. The combination of the deepwater propagation and inundation model out -put will then be used to provide information and tools for emergency management and infrastructure planning in the SW Pacific. However, detailed tsunami inundation modelling can only be undertaken if bathymetry (seafloor mapping) and topographic (land elevation or height) data of adequate quality and coverage exist.

SOPAC, through EU funded projects, has been addressing the some of the needs in the Pacific Region for high -resolution bathymetry data. This data is underpinning a number of critical technical projects in the areas of marine boundaries, fisheries, coastal processes, and in hydrodynamic modelling for projects in support of reducing impacts of aggregate mining etc. However there is very little in the way of high resolution coastal and inter -tidal topography data available in the Pacific region that is suitable for inundation and sea -level change modelling and monitoring. There is a distinct possibility that the issue of inadequate topographic data in many Pacific Island Countries (PICs) and the limiting effect this may have on tsunami and other inundation modelling may require consideration of options to improve coastal topographic data collection by methods such as LIDAR.

This report for Solomon Islands is the fourth of a series of reports and reviews the availability of high resolution inshore bathymetry and also inter -tidal and coastal topography of low lying coastal areas. The reports completed so far (Pearce, 2007a -c) are available through the Pacific Disaster Net and the SOPAC virtual library.

Geographical information and location of Solomon Islands are at Table 1 and Figure 1.

Table 1: Geographic Information for Solomon Islands ( http: / /www.sopac.orq /tiki /tiki- index.php ?page = Solomon +Islands).

Capital: Honiara Population: 409, 042 (1999) Land Area: 28, 785 sq. kilometres Max Height (above Sea -level): 2, 447 m (Mt. Makarakombou) EEZ: 1, 340, 000 sq. kilometres

Rainfall: Varies from 3,000 - 5,000 mm per annum Mean Temperature: 26 °C GDP per Capita: SB $584 (2002) Currency: Solomon Island Dollar (SB$) Languages: English (official), Pidgin and 87 other languages Government: Independent State and Member of the Commonwealth SOPAC Membership: Joined in 1972 as full members of SOPAC (then CCOP /SOPAC)

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PAPUA NEW South \GUINEA Pacific Choiseut Ocean Santa fsabef Gizo Yandina `Malaita HON IARA ® GUOCISIrarr74ri ihOIL Santa Cruz Solomon San 'stands Cristobai

Coral Sea VANUATU

0 150 300 km ß 1$O 300 rni

Figure 1: Location of Solomon Islands.

2 SOURCES OF TSUNAMI HAZARD

Major subduction zones are the predominant source of earthquakes large enough to generate regional or ocean -wide tsunami. They are the main focus of the preliminary hazard analysis report (Thomas et al. 2007) which models magnitude 8.5 and 9.0 earthquake source tsunami generation (as discussed in section 4). The location and names of these subduction zones are shown below in Figure 2. The Solomon Islands are located very close to a major source, the Solomons Trench.

Tsunami can also be generated from other processes such as meteors, volcanic eruption, volcanic collapse and submarine landslide. The latter are often triggered by earthquakes and are commonly attributed to the earthquake. Steep sloped bathymetry on volcanic and other islands and submarine volcanoes may have the potential to slump or collapse and depending of the size of such collapses these events may cause local tsunami. The location of the 3 major volcanos, Kavachi, Savo and Tinakula are shown at Figure 3. Small tsunami were observed from Kavachi in 1955 and from Tinakula in 1966 and 1971.

A table of the causal earthquake criteria for local, regional and ocean -wide tsunami (i.e. 100 km, 1000 km, >1000 km) and the range of expected destructive impact, similar to that used for warning purposes by the Japan Meteorological Agency (JMA), Pacific Tsunami Warning Centre (PTWC) and Australian Tsunami Alert Service (ATAS) is described in Appendix 2 Section (ii)Table A2 -3. The PTWC Bulletins are issued as advice to government agencies. Only national and local government agencies have the authority to make decisions regarding the official state of alert in their area and any actions to be taken in response.

There is a sea level recording site in Honiara since 1992, operated by the Australian Bureau of Meteorology (ABoM). Recorded historical earthquake and volcanic generated tsunami events affecting the Solomon Islands are discussed at Appendix 2, along with examples of PTWC bulletins issued for the 2 April 2007 tsunami and the smaller Santa Cruz 2 September 2007 tsunami. The period of records available is short compared to the recurrence interval of large events on the Solomons Trench. More work could be done to collect paleo- seismic and paleo- tsunami

[SOPAC Miscellaneous Report 654 - Pearce] [7]

information and oral history of tsunami in the region to assist with estimates of probabilities of events associated with that source.

Continental Rift - Oceanic Spreading - Continental Transform Oceanic Transform Continental Convergent Oceanic Convergent - Subduction Zone 60`

40`

20`

o°

-20'

_40°

-60' 120° 140° 160° 180° 200° 220° 240° 260° 280° Figure 2: Map of Major plate boundaries in Pacific Ocean with subduction zones labelled as follows: AIT- Aleutian Trench, ChT- Chile Trench CsT- Cascadia Trough, HT- Hikurangi Trough, IBT- Izu Bonin Trench, JpT- Japan Trench, KmT- Kermadec Trench, KrT- Kuril Trench, MT- Mariana Trench, MAT- Middle America Trench, NT- Nankai Trench, NGT- New Guinea Trench, NHT- New Hebrides Trench, PhT- Philippines Trench, PTT- Peru Trench, PyT- Puysegur Trench, RT- Ryukyu Trench, SST- South Solomons Trench, TnT- Tonga Trench. Subduction Plate margins are shown in blue and are the source of the largest earthquakes in history (Thomaset al.2007). Locations of Solomon Islands is marked in purple.

Major Volcanoes of Solomon Islands

South APIA NEW Pacific Kavachi Ocean

4 ` Savo 5.SOLOMON ISLANDS Honiara -- Solomon Sea Tinakula

Cora! Sea VANUATUo,_

300 km 300 mi

Topnka IJSGSICVO,2G oo;Basem&p waffled from MUMSCIA, 1999,' Volcanoes from Sirmkin&SieLert 1994 Figure 3: Major Volcanoes in Solomon Islands.

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3 VULNERABILITY /EXPOSURE

The Solomon Islands are very close to Solomons Trench to the southwest and to the northern part of the New Hebrides Trench to the south. They are also vulnerable from the NW from the Mariana, Western Aleutian and Nankai Trench sources.

Any local, regional or ocean -wide event generated by the Solomons Trench would reach parts of Solomons with minimal formal warning lead time, apart from feeling the earthquake. Any regional or ocean -wide event from New Hebrides Trench and eastern PNG (still part of Solomons Trench) would reach parts of the Solomon Islands within 3 hrs. Any ocean wide event from the NW sources would have 4 -10 hrs lead time for a warning to be disseminated.

The major island or submarine volcanos are potential sources of local tsunami. One of these, Savo, is located only 35 km NNW Honiara, the capital city of the Solomon Islands, Honiara a relatively highly populated area. It would be potentially vulnerable to any landslide generated tsunami from this source.

All the significant recorded tsunami run -up events in the Solomon Islands have been generated from the Solomons Trench e.g. the recent 2 April 2007 event near Ghizo, Beaufort Bay on the west coast of Gaudalcanal in 1939 and San Cristobal Island in 1931, Gaudalcanal in 1961 and Choiseul 1974 (Table A2 -1).

The 2 April 2007 tsunami reached parts of the coast within 10 minutes of the earthquake (Figure 4). This is insufficient lead time for formal warnings to be effective. Villagers very close to the source of the earthquake need to rely on public education, feeling the earthquake and self evacuation where appropriate. The further a region is from the source the more lead time is available to facilitate formal warning processes, e.g. the tsunami travel time to Honiara was approximately 40 minutes and to Kirakira on San Cristobal Island approximately 56 minutes.

400

600

E -800

-1000

-1200

-1400 i i i i r -600 .100 200 0 200 400 600 800 1000

X [km] Figure 4: Post tsunami modelling at 10 minutes after the 2 April 2007 earthquake, showing extremely short lead time before the tsunami generated on the Solomons Trench reached populated areas of Solomon Islands. Red represents wave peak, blue the wave trough. (Tomitaet al.2007).

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The prior knowledge of potential impacts from various sources, both close to and distant from the Solomon Islands, is therefore critical. With the deepwater modelling as input into island specific, finer resolution tsunami inundation models, a greater understanding of the potential risk and possible impacts of tsunami may be realised. It will then be extremely important to communicate the comparative risks and consequences within all hazard frameworks and action plans. It should be noted however that accurate detailed tsunami inundation modelling can only be undertaken where adequate bathymetric (seafloor mapping) and topographic (land height or elevation) information exists.

Tsunami generating mechanisms are themselves not known to be impacted on by climate change directly. However, climate change may impact indirectly (Figure 5) by reducing the innate resilience of coastal systems; e.g. increased sea -level, erosion, etc. and thereby, leave coastal communities in a position of greater vulnerability. A further example is the timing of impact with sea state and high tides; e.g. if a tsunami arrives during a spring low tide the impacts would be less than if it arrived during a spring high tide (Appendix 1 Section 3).

['nuaul hluurd rmarnc pnrrnr rnFlnrnred by elnn11e rhunge

SST Storms cyclones (winds pressure) Sea level (Seasonal. ENSO. IPO) Earth slides ! earthquakes tect onic movements 1 Tides1 Sediment Tsunami Sea level Storm tide CiuTents Waves & movement & change swell supply AL IL V .61 .1. Coastal inundation N C.J x Coastal erosion 1111 11M1

Figure 5:Tsunami generation not directly influenced by climate change, however indirectly influences impact (Glasseyet al.2005).

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4 OVERVIEW OF TSUNAMI HAZARD AFFECTING SW PACIFIC

A deterministic broad scale tsunami hazard assessment for the SW Pacific based on the deep - water tsunami propagation model was conducted (Thomas et al., 2007) by Geoscience Australia focusing on the major subduction zone sources (Figure 2) around the Pacific. Section (i) below contains summary extracts from that report and section (ii) contains extracts specific to Solomon Islands and some added interpretation. Solomon Islands were ranked Category 5 (Suite 1) and 5 (Suite 2) in the preliminary deep -water tsunami hazard study (these categories are explained below).

(i) Summary Extracts:

"To aid in interpretation of the results, offshore tsunami amplitudes have been categorized into 5 ranges (Table 1). Categories corresponding to a higher range of offshore tsunami amplitudes can presumably be associated with a higher level of hazard on coastlines of similar type. This categorization has been adopted throughout this report. It is important to note, however, that these ranges do not reflect the inundation that normally causes damage and /or fatalities and which can often vary widely depending on local bathymetry and topography. The categories indicated in Table 1 are therefore best viewed as indicating a relative level of hazard over areas of broad geographic extent. For example, a Category 5 tsunami along the coast of Papua New Guinea represents a higher level of hazard than a Category 2 tsunami along the coast of New Caledonia.

It is premature, however, to interpret Table 1 in terms of impacts. This is especially true for low -lying atolls such as Tuvalu and Kiribati. On the one hand, the lack of any high ground may appear to make these islands especially vulnerable to tsunami, so that even a Category 2 tsunami may be a cause for serious concern. On the other hand, because such atolls often have steep drop -offs in which ocean depths increase very rapidly with distance from the fringing reef, there may not be a pronounced shoaling effect, so that these islands may never experience a large tsunami. Such considerations require much more modelling to address and are beyond the scope of the present study, although it is intended that they be considered in a later phase of this project. In particular, the information presented in this report should not be used as a guide for responding to tsunami warnings. The information presented here is preliminary and is only intended as a rough guide for prioritizing work in subsequent phases of this project.

Table 1: Categorisation of offshore tsunami amplitudes, normalised to equivalent depth of 50metres. The "Colour " column refers to the colour used for amplitudes of this category which have been used throughout this report

CfltegoryNarrna]ised Amplitude (em) IC.83our I 0-2rr _M_ 2 25 -75 8 75-150

4 150 - 250 ]

G > 250 II

Tsunami generated by two suites of simulated earthquakes were studied: Suite 1, consisted of 187 moment magnitude (Mw) 8.5 earthquakes, and Suite 2 comprised 39 Mw 9.0 earthquakes (Figures 5 and 7, pages 11 and 13). The results are summarised in Table 2. For both suites of earthquakes the nations most affected were in the south and west of the study area, including Vanuatu, Papua New Guinea, Guam, Solomon Islands and Tonga, each of which recorded Category 5 amplitude tsunami from the Suite 1 (Mw 8.5 earthquakes). This is due to the proximity of these countries to the subduction zones and the orientation of the fault lines which acts to direct the tsunami towards these nations "...

...Nations in the north and east of the study area, such as Kiribati, Marshall Islands, Nauru, Cook Islands, French Polynesia and Tuvalu were much less affected by the Suite 1 tsunami and only experienced Category 1 or 2 sized waves. As is to be expected, Suite 2 events produced greater effects than those of Suite 1 on all nations. Notable in this respect is Fiji which experienced Category 5 amplitudes from Suite 2 events. However it should be

[SOPAC Miscellaneous Report 654 - Pearce] noted that without further investigation it is not possible to say that even Category 2 amplitudes will not produce significant run -up at some locations.

The figures in Appendix A show that Suite 1 events (Mw = 8.5) from the subduction zones in the eastern and far northern rims of the Pacific did not produce effects larger than Category 2 on any of the nations studied. However some Suite 2 events (Mw = 9.0) in the Peru - Chile, Aleutians and Kuril subduction zones did produce Category 3 or above effects for some nations

Table 2:Summaryofresults. Categories represent the highest amplitude recorded for that nation, and should be interpreted according to Table 1.

C attiFÿo ry Suit 1 SUlt-E' 2 rnoeicari .Sauur a :! 3 Cook Lsl;ilydh ! t

Fiji :-0 5 :iFrench Poly i1iSl"zl } a G u mu ,1 5 Kiribati 2 a Mar 611 all I.-1;J ud.5 _' 3 VS. 4F Micronesia .1

N;-1l3ru 1 '? Ncs. Cal C.r3anin .E 4 Mlle $ 4 Ps1 au 3 4 Piip118 New Gliilleil 5

5aln0ul -E 4 ., So loamL Islsnd5 5 TorxE;e4 s 5 Tuvalu ? 1 VA> 1u:l t u G 5

....Events from Suite 1 in the subduction zones of the east, north and northwest rim of the Pacific have less effect on the region, either because of their distance, because the orientation of the fault lines acts to direct tsunami energy away from the region, or because of intervening bathymetric features. They rarely produced normalised amplitudes greater than Category 1, and never greater than Category 2.

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Table 3: Most significant source regions for each nation, based on model out put points that recorded a maximum amplitude exceeding 75 centimetres for Suite 1 (Mw 8.5).

Nation Maximum Am-Most Significant Source plitudeforallRegions (amplitude Tide Gaugesgreaterthan75cmat for all Mw 8.550m depth or single most Tsunami (cm) significant source region if no amplitude exceeds 75cm American Samoa 92 Tonga Cook Lslands 44 Tonga Fiji 140 Tonga, Kermadec, New He- brides French Polynesia 50 Tonga Guani 300 Mariana, 12u -Bonin Kiribati 49 Peru Marshall Islands 40 New Hebrides F.S. of Micronesia 160 Marina, New Guinea, Philip- pines. South Solomons Nauru 20 South Solomons New Caledonia 160 New Hebrides, South Solomon Niue 110 Tonga Palau 130 Philippines, New Guinea Papau New Guinea. 310 South Solomon, New Guinea, Mariana Samoa 160 Tonga Solomon Islands 290 South Solomons, New He- brides Tonga 260 Tonga Tavahi 57 New Hebrides Vanuatu 380 New Hebrides, South Solomon, Tonga, Kermadec

....This modelling pays no regard to the probability of events of various magnitudes occurring on any of these subduction zones. While there is no doubt that the Chile sub -duction zone can host an earthquake exceeding Mw 9.0 (the 1960 event was magnitude 9.5) there is as yet no consensus on a reliable method of determining the absolute maximum magnitude on any given subduction zone. We believe that most seismologists would agree that a magnitude 8.5 event is plausible on any of the subduction zones considered here, and that a 9.0 event is impossible to rule out. Hence we consider both magnitudes. A probabilistic tsunami hazard study would consider a range of earthquake magnitudes and weight them according to estimates of their likelihood, in a similar way to the method described in Burbidge et al, (2007).

....Like Suite 1, the nations most affected by the Suite 2 events were those in the south and west of the study area, as a result of the subduction zones in that region. However the plots in Appendix A show that Suite 2 events in the Chile -Peru, Cascadia, Aleutians and Kuril subduction zones produced significant (Category 3 or above) normalised amplitudes for some nations. For example the simulations indicate that the Chile -Peru zone is a significant source of hazard from Mw 9.0 events for Fiji and French Polynesia, as are the Aleutian and Kuril subduction zones for Guam, Federated States of Micronesia, Papua New Guinea, the Solomon Islands and Vanuatu. Significant normalised amplitudes were produced in Papua New Guinea and the Solomon Islands from modelled events in the Cascadia Subduction Zone.

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Table 4: Most significant source regions for each nation, based on model out -put points that recorded a maximum amplitude exceeding 75 centimetres for Suite 2 (Mw 9). Nation Maximum Am-Most Significant Source Re- plitude forallgions (amplitude greater than Tide Gauges75cm at 50m depth or single forall Mw 9most significant source region if Tsunami (cm) no amplitude exceeds 75cm ) American Samoa 140 Tonga C, 3ok Islands 160 Tonga Fiji 390 Tonga, Kermadec, New Hebrides, South Solomon, Aleutian, Peru, Chile French Polynesia 120 Tonga.Kermadec,Peru,Chile. Aleutian Guam 430 Mariana, Philippines. Ryukyu, Nankai, New Guinea,Aleutian, Izu -Bonin Kiribati 99 Peru Marshall Islands 110 Kuril, Mariana Micronesia 230 Mariana, Philippines, New Guinea, South Solomon. Aleuti:i.ns. Nankai, Ryukyu Nauru 31 South Solomons New Caledonia 240 New Hebrides,South Solomon& Tonga, Kermadec Niue 210 Tonga Palau 240 Philippines, Mariana, Ryukyu, Nankai, New Guinea Papau New Guinea 340 South Solomon, Mariana, New Guinea,Nankai,Ryukyu, Aleu- tians, Kuril, New Hebrides, Philip - lunes Samoa 190 Tonga Solomon Islands 310 South Solomon, New Hebrides, Aleutians, Mariana, Ryukyu, Nankai Tonga 330 Tonga, New Hebrides, Kermadec Tuvalu 88 New Hebrides Vanuatu 450 New Hebrides, Tonga, Aleutians, South Solomons, Kermadec, Kuril, Nankai- Ryukyu

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(ii) Summary and Interpretation for Solomon Islands

(a) Composite of Deep -water Tsunami generated by 8.5 Mw Sources around Pacific Based on Figure 6 and 7 below, for an 8.5 Mw generated tsunami event, the Solomon Islands Trench source has the potential to generate deep -water tsunami of Category 4 and 5 for parts of the Solomons. The Northern New Hebrides Trench has the potential to produce Category 3. The New Guinea, Southern New Hebrides, Mariana, and parts of Kuril, Western Aleutian, Northern Tonga and Kermadec Trenches have the potential to produce Category 2. Other more distant sources only have the potential is only for Category 1. 120' 140" 160' 180' 200" 220 240` 260" 280' 300' 60

40

20'

0'

-20'

-40'

-60' cm 025 75 150 250 600

Figure 6: Composite of normalised source 8.5 Mw deep -water tsunami for Pacific. Maximum wave heights for the 187 tsunami of suite normalised to a standard depth of 50 m using Green's Law (Thomas et al. 2007).

Figure 7: Magnitude 8.5 earthquakes ranked by the Category of offshore tsunami they could cause at Solomon Islands. Each bar is displayed at the position of a magnitude 8.5 earthquake for which a tsunami was modelled, and the height and colour of the bar indicates the Category (Section 4 Table 1.) of the offshore tsunami modelled in Solomon Islands (Thomaset al.2007).

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(b) Composite of Deep -water Tsunami generated by 9.0 Mw Sources around Pacific.

Based on Figure 8 and 9 below, for a 9 Mw generated tsunami event, the South Solomons Trench sources have the potential to generate deep -water tsunami of Category 4 and 5 for parts of Solomons. The New Hebrides to the south and Mariana, Western Aleutian, Nankai and Kuril, sources to the northwest, have the potential to generate category 3 for parts of Solomon Islands. Japan, Izu- Bonin, Philippines, Central Aleutian, Cascadia, Peru and parts of Chile trenches have the potential to produce Category 2. The other sources have only the potential to generate Category 1.

120 140 160 180` 200 220 240 260 280 300

3I cm 0 25 75 150 250 :70

Figure 8: Composite of normalised source 9 Mw Tsunami for Pacific. Maximum wave heights for the 39 tsunami normalised to a standard depth of 50 metres using Green's Law (Thomas et al. 2007)

co

U

U

'2o

Figure 9: Magnitude 9 earthquakes ranked by the Category of offshore tsunami they could cause at Solomon Islands. Each bar is displayed at the position of a magnitude 8.5 earthquake for which a tsunami was modelled, and the height and colour of the bar indicates the Category (Section 4 Table 1.) of the offshore tsunami modelled in Solomon Islands (Thomas et al. 2007).

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5 Data Available at SOPAC for Inundation Modelling

Global bathymetry and topography data sets were sufficient for the deep -water tsunami modelling used in the preliminary hazard assessment (Thomaset al.2007). However inundation modelling, as does storm surge modelling, requires significantly higher resolution bathymetry as well as inter- tidal and coastal topography than the deep -water propagation models.

A review of the data available at SOPAC to support inundation modelling has been conducted.

(i) Bathymetry Datasets and Marine Charts

Global Deep Water Bathymetry

S2004 (Global 1 minute, -2km): Available via ftp from ftp: / /falcon.grdl.noaa.gov /pub /walter /Gebco SandS blend.bi2. S2004 merges the satellite altimeter data derived Smith and Sandwell (1997) grid with GEBCO over shallow depths (Marks and Smith, 2006).

Hydrographic Charts

A range of hydrographic charts at various scales are listed below with examples of coverage in Figures 10 -12.

avo

, -._

SEALARK CHANNEL AND PROACHES in HONIARA vtiar.ae,,...l i44 ,.ir :-_ ---

Figure 10: Sealark Channel and Approaches to Honiara: Datum Lat Mercator, WGS 72 1 :100,000 at Lat 9 15S. Also shows the location of the volcano Savo approximately 35 km from Honiara.

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Figure 11: Extract from Indispensable Strait 1:300,000 Mercator chart showing bathymetry of Guadalcanal and location of Beaufort Bay which had a recorded 10.5 m tsunami on 30 April 1939.

Figure 12: Extract of Ghizo Region from Choiseul Island to New Georgia Island (1979): Mercator, Datum LAT, WGS72, 1:300,000. Approaches to Ghizo Harbour (1976) 1:25,000 Projection Gnomonic DOS (1964) Datum: MHHW (not scanned)

Ghizo Harbour (1976) 1:12,500, Projection Gnomonic DOS (1964) Datum: MHHW (not scanned)

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Fair -sheets A range of additional bathymetry data is available from Australian Hydrographic Office (AHO) (Figures 13 -14) and the Solomon Islands Hydrographic Office (Figure 15) Fair Sheet holdings. Some of this data is in digital form and some is scanned hand drawn plots.

Legend

GA Digital Holdings oIAHD RANs data

I IGA Digital Holdings of AHO dald GA Digital Holdings 01 Swath dala E-11 World - Polygons

0 100200 400 1Glomele.s

1 1, i+ 1 i 1 i I

Figure 13: GA holdings of AHO Fair Sheet data.

Geoscience Australia Hydro Survey Holdings - Solomon Islands

.mw..,.,,.tl..a, Pod A Di wo.rc.wwar dm.....-i.e.a.e

.wire

Nplfvlian [mpme M ," Auuralia

LmAr .r.cv

&wm`y

a... ©v,...r+,.-

Figure 14: More detailed view of AHO Fair Sheet holdings for area between Guadalcanal and Malaita.

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[.1 11'/.[ 11 1:11{ Bi ll : li 11' i 9{I L]C H k5 ¡¡`nn L%' .21-t " -.¡f.

- 1 ' - ` --

Figure 15: Solomon Islands Hydrographic Office Fair Sheets for Ghizo area.

Other bathymetry Surveys

RV L'Atalante survey data using a Simrad EM12 multi -beam system, during the SOPACMAPS Project, Leg 2, 19 August to 16 September, 1993. Shown as contours without colour on Figure 18.

Single beam survey Marovo by University of Queensland (2005) shown in Figure 20.

SOPAC /EU Surveys SOPAC conducted bathymetry surveys in June and July 2005 covering Honiara, Marovo, Noro and Ghizo. The locations are shown in Figure 16 and in more detail in Figure 17 and the bathymetry data at Figures 18 to 22. The background to priority of the surveys for the various locations: Ghizo: area which is relevant for aquaculture /pearl farming, tourism and marine protected areas. Iron Bottom Sound (Honiara): Bathymetric survey to obtain physical oceanographic data in order to generate management maps and hydrodynamic models to identify and manage risk of oil leakage from war relics and sewage outfall from Honiara Marovo Lagoon: Generate management maps and hydrodynamic models to track dispersal of silt from deforestation on Vangunu. This area is a proposed World Heritage site important for tourism and fisheries. Noro: Survey to characterise pollution from fish cannery and provide baseline information for a hydrodynamics model.

Information on coverage area and maximum depth are at Table 2 and formats of data sets at Table 2.

Table 2: Locations of SOPAC /EU bathymetry surveys

[SOPAC Miscellaneous Report 654 - Pearce] [20]

Location Area covered by MBES Maximum depth of coverage Ghizo Up to 2 km off the barrier reef with 500 m shallow water coverage inside the reef system. Honiara 40 km offshore 1150 m Marovo 5 km inside the reef systems 500 m Noro 7.5 km off the eastern barrier reef 400 m

4°S

6°S_ i

1111111" 8°S Giz000Márovo \Noro 0 Honiara 1o°S

12°S

14°S

16°S

156°E 158°E 160°E 162 °E 164 °E 166°E 168°E 170 °E 172 °E

Figure 16: Solomon Islands EEZ showing locations of recent SOPAC /EU surveys.

MA ISABEL VELLA LA VELLA DAI

RANONGGA GEORGIA BUALA

SIMBO

VANGUNU

WESTERN TE7EPARE--- Kavachf CENTR L FLORIDA sxix

0 50 100 kilometers GUADALCANAL

Figure 17: Locations of recent SOPAC /EU bathymetry surveys in Western and Central Guadalcanal regions (Kruger, 2007).

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Table 3: Formats for SOPAC /EU Bathymetry Survey data.

File type : Description F' D F Print ready AO -sized ohait of the multibeam bathymetry data at appropriate scales. Charts often include insetsof shaded relief, slope angle, and three dimensional perspective ima eg s. TÌF h associatedFilled colour contours in raster TIFF format. Mapinfo users can Mapinfo TABfile,anduse the TAB file to open the contours as a backdrop image. TFW world file. Other GIS users can import the image with the reference information contained in the TFW file and the projection stated on the PDF chart. XYZ Processed and comma delimited ASCII listing of X.Y,1 gridded survey points (Easting, Northing, Depth). GRD Binary grid file of the points contained in the XYZ file in the Golden Software Suffer format. Many GIS packages accept this file for surface modelling.

There is reasonable bathymetry coverage around Ghizo and Honiara however there are gaps in the inshore shallow areas. Satellite derived bathymetry (from QuickBird or other satellites) could be an option for filling in gaps in coverage. Satellite bathymetry usually is only viable for depths less than 20 m. The timeframe and effectiveness of this option needs to be investigated further to establish viability and cost effectiveness.

[SOPAC Miscellaneous Report 654 - Pearce] [22]

= ir

..,,- ._.

HALL f r-aJr.% _ i

SOPAC I .

1 ,,._...,.e.,..r

tA..pK6RMKw.

Figure 18:SOPAC /EU Honiara Survey with previous 1993 survey contours shown without colour (Kruger & Kumar, 2007).

[SOPAC Miscellaneous Report 654- Pearce] [23]

;PEN,

r

Meg.. pso1

b. nna SOPAC

...... wP,._

blab 0.^E.= cab, 1.0.1 PEER KNEW Figure 19: SOPAC /EU bathymetry for Ghizo (Kruger & Kumar 2007).

[SOPAC Miscellaneous Report 654- Pearce] [24]

LIEMID ..,,.....

Oporognorp ix .041a

S OFA

...... ,10Ar-f

,e...... MP. . KNEW'..,....

Figure 20: SOPAC /EU bathymetry for Marovo (Kruger & Kumar, 2007).

[SOPAC Miscellaneous Report 654- Pearce] [25]

LENNO

ilm...... b...... ,.u....

CNAANNNAI b

Iro

r. raw INN! NN ONN

Now WM ONLAAN 4NANNNAN Ao M:

NOA,C,O ANCO on NOW..

MOOING INonadANCN

OAANna

almw aiN Non

r, 74157,

nro SQrpC

IMO IIANINNLTNI oENRINA `PUP a.,. ANA:. OWN Figure 21:SOPAC /EU bathymetry for Noro (Kruger & Kumar, 2007).

[SOPAC Miscellaneous Report 654- Pearce] [26]

(ii) Satellite Imagery

Landsat data is available for the Solomon Islands, 30m resolution.

SOPAC has also purchasing QuickBird pan sharpened (60cm resolution) data for:

Island Area (Km Sq) Vella Lavella 327 Ranonga 262 Ghizo 267 Kolombangara 236 Rendova 281 and IKONOS imagery for Ghizo, as the Quickbird image was of poor quality due to cloud cover.

(iii)Topography, Coastline and Reefs

(a) Topographic Maps are available at: 1:50,000 (1968 -75) with 20m contours (including Honiara and Ghizo) 1:10,000 with (1969- 1975)10m contours (datum MHWM 0.2m above MSL) 1:2,500 (1969 -1975) Parts of Honiara township (datum MHWM 0.2m above MSL)

(b) Contours at 20 m intervals digitised from 50,000 topographic maps.

(c) Coastline defined as (MSL or MHWM) and reefs digitised from topographic maps and varying resolution satellite imagery. Sources and metadata not available. This may need to be redone from Quickbird imagery.

(d) DEM /DSM Space Shuttle Topography Mission 90m grid for all of Solomon Islands, WGS84, Geodetic, MSL. Data Directory: http://seamless.usqs.qov. This is far too coarse for inundation modelling requirements.

Digital Surface Model (DSM) with 5m vertical accuracy available in Solomon Islands. Specifications at Table 4 below.

The accuracy of the topography in the range MSL to 5m has a significant impact on the quality and credibility of any tsunami inundation modelling. The Digital Surface Model represents the tops of trees and buildings rather than the ground as per a Digital Elevation Model (DEM) or Digital Terrain Model (DTM). The satellite DEM is very coarse and the suitability of the DSM for inundation modelling will be limited unless addition information is available to better define the low lying topography in critical areas.

Table 4: Metadata for DSM

[SOPAC Miscellaneous Report 654 - Pearce] [27]

Solomon Islands Datasets

Totaling 27,000 sq. km., the Solomon Islands datasets are the result of one of Intermap's countywide mapping projects. Our product offerings indude elevation data and orthorectified radar imagery fORI). The elevation data available is a digital surface model (DSM) of the first return of the radar signal from free canopies. buildings, and other cultural features. The ORI provides our users with an enhanced image mith a 1.25 mground resolution.

All datasets for the Solomon Islands are available for sale through the Intermap Store.

Solomon Islands Product Specifications

Vertical datum (geoid MOL as referenced to EGM9E model):

Horizontal (geodetic) 1.VGS84 datum:

Projection: UTM

32 -bit floating point binary grid format File format (f3SM and DTM): (.bil)

File format {ORI): 8 -bit unsigned GeoTIFF format (.tif)

ORI Measures of Horizontal Accuracy (in)

Pixel Size RMSE

1.25 2.0

DSM Measures of Vertical Accuracy ( m)

Product Type Post Spadng RMSE

III 5 3.0 JI

(iv) Infrastructure data

Honiara was part of the Pacific Cities project in 1998. This project collected infrastructure in GIS format for a number of Pacific Cities. It would need some updating from satellite imagery. Ghizo was not part of Pacific cities project therefore infrastructure data is limited, however it could also be supplemented from satellite imagery.

(v) Post tsunami inundation /run -up data

The only international sea level monitoring gauge is in Honiara. Although it recorded the tsunami it was outside the main affected area. Post the 2 April 2007 Tsunami event a number of international technical survey teams measured tsunami run -up, inundation and land level changes in the most affected areas. Figure 22 shows the survey points for the McAdoo team, Nishimura team and Tomita team surveys and are discussed in Kruger 2007. Figure 23 the run- up and inundation heights from the Tomita survey (Tomita et al. 2007). Figure 24 shows the locations and heights for the Fritz team (Fritz & Kalligeris, 2008) survey:

These surveys results will provide and excellent opportunity to calibrate and verify any inundation modelling undertaken for this region.

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Solomon Islands Western Province Area affectedbythe 2 April 2907 Earthquake and Tsunami

Sovey Location Pointe O McAdoo ofal. Nishimura ¡Atli. Tornitaof ai.

Vella Lavella 9IsIan b I Kolomhangara EX '"an. Island

NJan anvnaga o Island IsRland tQ. Ghiro Islam, 4c Makuti °D. Island

Nusa Aghana '

Simhv

0 5 10 20 30 40 Km Figure 22: Location of post 2 April tsunami event surveys for 3 teams, Mc Adoo et al, Nishimura et al and Tomita et al.

Ama E i5 locPE h-ebä§e'm'is f Potential Tsunami -Affected. -Areas : --Solomon lsfandsrllefòñ1:O7 kiiyaltOS AT. 2.9 --. _ m r_"1ÆLLA i'.AVkdEA lStAND rfi. r ,'.-n 1446L413AfI^Af;l1 F _+ .iì4 s".: '` }% ' .-- `{avAr , ,. .` L: .iá8-' '4lemxni II . ..I.'` o't..F _.+, ¡41 .. v l'f ' 't.i ,. -.- Reo. i m W.Va. .ipvo,ki i 5. t+

$Addl_ r f lSLAIYD ti

Giao .. ,nektrboe/,.__ dlk+ltn[á--- ,. f R V-Iaigalil

rapan44 Mal , m ar4va inurlati.on'. 2.71n.

3.7m e.ou T rlan m A,A-r._.-. -O!Apfü zafo. 4n jap %s/hifali z0,$ §, alar. { `- 4kifi-- r4.4w359r .6m .26,1$m ; *LANA. : New Manra 15

Figure 23: Post tsunami survey information on run -ups and inundation heights (metres) from 2 April Tsunami in Solomon Islands (Tomita et al. 2007).

[SOPAC Miscellaneous Report 654 - Pearce] [29]

r 12 Simbo lo 8

2 I..200 Australia Li-0° 15 -2

e tsunami runup tsunami height uplift/subsidence- alb -Sasamunga. . . Ir (Choiseul)

Vella Lavella¡le.

G h izo . Ranongcga Simbo

. . Ren dova "

1210 8 6 4 2 0 -2 156 157c height [m]

Figure 24: Post 2 April 2007 tsunami survey information (Fritz & Kalligeris, 2008). Measured tsunami run -up (red) tsunami heights (blue) and land level changes (green).

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(vi) Data Summary

Table 5: Summary of available data

Type Resolution Metadata Datum /Projection Format available Bathymetry S2004 Global 1 minute, Yes WGS 84 /MSL ASCII grid, xyz -2km Deep -water Multibeam Various Yes UTM 57S,WGS 84, /LAT xyz Survey data

AHO Fair Sheets various yes Mercator /UTM Zone 57S, Contours only WGS 72/ LAT RV L'Atalante 1993 50m contours

Honiara Various Ghizo Marovo Noro

Surfer .grd) Grid created from Survey data Honiara 100m Ghizo 20m Marovo 20m Noro 50m Mapinfo Contours Mapinfo Backdrop 10m to 50m then 50m intervals Marine charts Honiara 1:300,000&1:2,500 Yes Mercator /UTM Zone 57S, Paper /scanned Ghizo 1:100,000 WGS 72/ LAT Paper /scanned 1;25,000 Satellite derived Could be option to None yet bathymetry fill in gaps Coastlines Outline Various No UTM Zone 57S, WGS 84, Mapinfo MSL or LAT? Lines Reefs Platform No UTM Zone 57S, WGS 84 Topography Topographic maps UTM 57S, WGS 72, MSL All Solomon's 1: 50,000 (1968 -75) Paper Chart with 20m contours (including Honiara and Ghizo)

Honiara 1: 10000(1969 -1975) with 10m contours (datum MHWM 0.2m above MSL) 1:2500 (1969 -1975) Parts of Honiara township (datum MHWM 0.2m above MSL) Mapinfo Lines

Contours Digitised No from maps. Digitised Contours Spot values None

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(All Solomon Islands) Satellite DEM 90m yes WGS 84,MSL

Digital Surface Model 5m (Expected to UTM, WGS 84, MSL (DSM) become available)

Imagery Landsat 30m Yes UTM 57S, WGS 84 Geo- referenced TIF (Mapinfo) Quickbird 0.6m pansharpened Yes Vellalavalle Kanongo Ghizo Kolombangara Rendova

Infrastructure Honiara Digitised from Pacific Cities UTM 57S, WGS 84 Mapinfo Roads 1:10000 and 1:2500 project CD Lines /polygons Wharf and satellite imagery Airport Buildings

Ghizo Digitised from No UTM 57S, WGS 84 Roads 1:50,000 maps and Wharf satellite imagery Airport Buildings

Tsunami Run -up Data Ghizo various yes WGS, MSL xyz Rendova Simbo Choiseul Vella Lavella

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6 SUMMARY

There are three main issues that will influence the priorities for and ability to do tsunami inundation modelling in Pacific: Hazard Category from deep -water modelling Vulnerability /Exposure Availability of high resolution bathymetry, and inter -tidal and coastal topography data

The extracts from the National Geophysical Data Centre (NGDC), Tsunami Inundation in Table A2 -1, show that for the tsunami that have been recorded all the most significant recorded events are from the Solomons Trench source with a few regional events from eastern PNG (still attributed to Solomons Trench) and Vanuatu (New Hebrides Trench). There were two recorded events from Russia, although the recorded run -ups for these are less than 1 m.

The Solomon Islands are ranked Category 5 for both the 8.5 Mw and 9 Mw Solomons Trench source in the preliminary tsunami hazard study based on deep -water modelling (Section 3 and Figures A3 -1 (31, 32, and 33)). Travel times to the Solomon Islands from this trench would be very short, providing minimal opportunity for formal warning. Other parts of the Solomon Islands are also vulnerable to Category 3 events from the NW (Figures A3 -1 (15, 16, 23, 25, and 26)); however these would have longer lead times for the formal warning process. The Solomon Islands also have 3 major volcanos, Kavachi, Savo and Tinakula which are possible sources of local tsunami. Small tsunami were observed from Kavachi in 1955 and Tinakula in 1966 and 1971

The bathymetry and topographic data sets available are not yet complete enough to be suitable for tsunami inundation modelling. There are significant gaps that would need to be addressed with lower resolution sources. There are two areas where data sets could be further developed. These are Ghizo in relation to the Solomons Trench tsunami source scenarios and Honiara in relation to a Savo volcanic cone collapse tsunami scenario. The resolution and quality of the bathymetry data sets between the Solomons Trench source to the south of Guadalcanal and the area around Honiara on the north, which has SOPAC /EU bathymetry data, limits the viability for modelling that source for Honiara. Satellite derived bathymetry may be a cost effective way of address gaps in the bathymetry for both Ghizo and near Savo and Honiara.

A bigger issue is the topographic and inter -tidal data. Unfortunately, the available contour maps and the Digital Surface Model (DSM) do not provide adequate definition of low lying areas. LIDAR data (Appendix 1 Section 2) of the coastal and inter tidal area would be ideal, but extremely expensive. It is uncertain at this stage whether the DSM can be improved or supplemented and this needs to be investigated further. The cost effectiveness of acquiring extra data or the effect of using poorer resolution data on the results of the modelling would need serious consideration.

The use of deep -water modelling from various sources as input into island specific, finer resolution inundation modelling is important for understanding the possible impacts and for communicating the comparative risk and consequences within the all hazard framework and action plans. However this is only possible where the data sets available can be improved to a sufficient quality and resolution to make this viable.

The post 2 April tsunami surveys of the run -up and inundation in the Ghizo area provide a critical data set for calibration and validation of an inundation model for the Ghizo area. Geoscience Australia as part of the next stage of the Hazard Assessment project will be looking at the options for improving the bathymetry and topographic datasets in order to take advantage of the opportunity to use the post event data to further validate the inundation model results.

[SOPAC Miscellaneous Report 654 - Pearce] [33]

7 REFERENCES

ABoM, 2007. Australian Bureau of Meteorology Web Site. http: / /www.bom.gov.au

Biukoto, L., Swamy, M., Shorten, G. G., Schmall, S., and Teakle, G. 2001. Pacific Cities CD, Honiara. GIS Hazards Dataset, Version 1.1. SOPAC Data Release

Burbidge, D., Cummins, P. and Mleczko, R. 2007. A Probablistic Tsunami Hazard Assessment for Western Australia. Report to the Fire and Emergency Services Authority of Western Australia, Geoscience Australia.

Cummins, P. 2007. The Solomon Islands Earthquake and Tsunami. Risk Research Group, Geoscience Australia.

Everingham, I. B. 1977. Preliminary catalogue of tsunami for the New Guinea / Solomon Islands region 1768 -1972, Dept of National Resources.

Glassey, P., Heron, D., Ramsey, D., & Salinger, J. 2005. Identifying Natural Hazards and the risk they pose to Tonga. GeosourceTonga, Study Report 4.

Fritz, H.M., & Kalligeris, N. (2008). Ancestral heritage saves tribes during 1 April2007 Solomon Islands tsunami, Geophys. Res. Lett., 35, L01607, doi:10.1029/2007GL031654.

Howorth, R., Elaise, A. 1997. Workshop on Volcanic Hazards and Emergency Management in the South Pacific. SOPAC Miscellaneous Report 245.

IAVCEI Workshop on Ulawun Decade Volcano, PNG. Volcanic Cone Collapses and Tsunami: Issues for Emergency Management in the Southwest Pacific Region. Geological Survey of Papua New Guinea and Australian Geological Survey Organisation, 1998.

Kruger, J. 2005. SOPAC /EU EDF8 Marine Survey Plan for Solomon Islands. SOPAC Report.

Kruger, J., & Kumar, S., 2007. (in prep) Bathymetry of Solomon Islands. EU -SOPAC Report.

Kruger, J., 2007. Solomon Islands: Geological Impacts of 2 April 2007 earthquake and tsunami on the islands and marine environment of the Western Provinces. SOPAC Country Mission and technical Advisory Report.

Marks, K.M., & Smith W. H. F. 2006. An evaluation of publicly available global bathymetry grids. Marine Geophysical Researches.

NGCD, 2007, NOAA /WDC Historical Tsunami Database http: / /www.ngdc.noaa.gov /seg /hazard /tsu db.shtml

PDC. 2005. Tsunami Awareness Kit (Solomon Islands) http://www.pdc.orq/PDCNewsWebArticles/2005TAK/index.html

Pearce, H., 2006. ATAS /AusTWC Decision Processes, NMOC, ABoM.

Pearce, H., 2007. (a) Inventory of Available Geospatial Data and Options for Tsunami Inundation & Risk Modelling, Tonga. SOPAC Miscellaneous Report MR651.

Pearce, H., 2007. (b) Inventory of Available Geospatial Data and Options for Tsunami Inundation & Risk Modelling, Niue. SOPAC Miscellaneous Report MR652.

[SOPAC Miscellaneous Report 654 - Pearce] [34]

Pearce, H., 2007. (c) Inventory of Geospatial Data and Options for Tsunami Inundation & Risk Modelling, Kiribati. SOPAC Miscellaneous Report MR653.

Pearce, H., 2008. Inventory of Geospatial Data and Options for Tsunami Inundation & Risk Modelling, Fiji Islands. SOPAC Miscellaneous Report MR655.

Pugh, D. 2004. Changing Sea Levels, Effects of Tides, Weather and Climate.

Smith, W. & Sandwell, D., 1997. Global seafloor topography from satellite altimetry and ship depth soundings, Science, v. 277, p. 1957 -1962, 26 Sept., 1997.

SPSLCMP Pacific Country Report, June 2005. Sea Level & Climate: Their Present State Solomon Islands.

SPSLCMP Strategic Review Report (in prep. June 2007) South Pacific Sea level & Climate Monitoring Project, Phase IV.

Thomas, C., Burbidge, D., & Cummins, P. 2007. A Preliminary Study into the Tsunami Hazard faced by Southwest Pacific Nations, Risk and Impact Analysis Group, Geoscience Australia

Tomita, T., Arikawa, T., Tatasumi, D., Honda, K., Higashino, H, Watanabe, K, and Takahashi, S., 2007 (in prep) Preliminary Report on Field Survey of Solomon Islands Earthquake in April 2007.

UNESCO ITIC, 2006. Tsunami Glossary http: / /ioc3.unesco.orq /itic /files /tsunami glossary.pdf

USGS 2007. United Stated Geological Survey web site, http: / /earthquake.usgs.gov/

Warne, J., 2007. Australian Tsunami Warning System Sea Level Observation System, ASLOS Network Design, Australian Bureau of Meteorology, (ABoM).

Wikipedia 2007. Tides, http: / /en.wikipedia.orq /wiki /Tide

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APPENDIX 1

Datum and Definitions

1 Datum and Geodetic Levels at Honiara, Solomon Islands

Sau." MANABA ISLAND Tuarugnú spue Maluú 'Kwaillbesi Solomon Ls Datum Reference SAN SANTA JORGE SABEL te kearch 1999 On metres) Gwaun ate. pU'a Sep°Vikenara Gape Ritters -Manu Point 'Oala Flu Bay esIwa e FBM 1 AukIA MountKolovrat 7.0761 FLORIDA lndÍspensable Bina FBM 4 (FIXED HEIGHT) H,ANH,ANAVISI ISLANDS oLEVUGA Strait u FendndiPoint 4.3102 All -"""'--- MALAITA KO EM, IJ 'G NGGELASIJLE Siota 'AIO Petupetu° Kusini ° Tulagn NGGELAPILE porn,. MOELAMII Baunan° SSBM M E KokamaN E S I A MBl1NGANA ISLAND qbungañ 4.2647 Mbahl SealarN Channel ..,,,,r Who Point'Tambooe Sura'-ró Lam. SEAFFIAME ' Tambunimane 1# Kaió ° Taro By Honiara RUA SURA ova ISLANDS g 1.40.-EP0.1.40.-EP Lambungasi Mere DALCANAL Kaoka BayBy 74 Velasi° Mount Pop BEAGLE PoposáISAND f Ra uremb0 visuPam,, yaw Nano `w&iere SANDS Pomi° aramakuru

Solomon Sea MEAN SEA LEVEL 10° 0.6905 1.° 160 °30' 161°

TIDE STAFF ZERO a.:aDOo

Figure Al -1: Datum for Honiara, Solomon Islands (SLCMP Country Report, 2005).

Mean Sea Level (MSL) in Figure Al -1 is the average recorded level over an extended period of time. MSL at Honiara is 0.6905 metres above the SEAFRAME datum (LAT).

[SOPAC Miscellaneous Report 654 - Pearce] [36]

2 Topographic Dataset Issues for PICs SOPAC is the regional agency with the technical capacity and tools to collect high quality bathymetric data and also supports PICs in the collection of spot land elevation data. However, SOPAC does not have the tools to support rapid collection of topographic information over broad scale areas. Such work is increasingly being undertaken remotely using tools which can measure large areas accurately and quickly, such as aircraft mounted LIDAR (Light Detection and Ranging - a remote sensing system used to collect topographic data over large areas quickly and accurately). There is a distinct possibility that the issue of inadequate topographic data in many PICs and the limiting effect this may have on tsunami inundation modelling may require consideration of such approaches to topographic data collection.

Twin Engine Aircraft Aircraft Elevation 700 meiern)

310. degree Scan Angle

Overlapping Swaths Scan Width S- 30.13 meters!

Flight Direclion (paralidtoYtO.0erYj

Figure Al -2: Schematic of an aircraft mountedLIDARsystem. Such systems are potentially capable of surveying shallow sub -tidal waters (too shallow for ship born bathymetry),intertidal zones, and topography ( www.csc.noaa.gov /products.htm).

[SOPAC Miscellaneous Report 654 - Pearce] [37]

3 Definitions and Acronyms

Permanent Mark or Ewen mark (P.M) or(B.M.)

Highest Astronomical Tide (HAT.)

Mean Higher High Water (M.H.H.W.)

Mean Lower High Water (M.L.H.W)

Australian Height Datum Wan Sea Level (M.S.L.) (A.H.D.i Mean Higher Low Water (WHIM.)

Mear Lower Low Water (M.L,L,W,)_

, Datum of Predictions Port Datum Lowest Astronomical Tide (L.A.T.)

Figure Al -3: Datum

HAT (highest astronomical tide) LAT (lowest astronomical tide) These are the highest and lowest levels which can be predicted to occur under average MHHW (mean higher high water)The height of MHHW is the mean of the higher of the two daily high waters over a long period of time. When only one high water occurs on a day, this is taken as the higher high water.

Meteorological effects on tides Meteorological conditions which differ from the average will cause corresponding differences between the predicted and the actual tide. Variations in tidal heights are mainly caused by strong or prolonged winds and by unusually high or low barometric pressure.

Tidal predictions are computed for average barometric pressure. Low pressure systems tend to raise sea -levels and high pressure systems tend to lower them. The water does not, however, adjust itself immediately to a change of pressure. It responds, rather, to the average change in pressure over a considerable area.

The effect of wind on sea -level and therefore on tidal heights and times is variable and depends on the topography of the area in question. In general, it can be said that wind will raise the sea -level in the direction towards which it is blowing. A strong wind blowing straight onshore will "pile up" the water and cause high waters to be higher than predicted, while winds blowing off the land will have the reverse effect.

MSL (mean sea level) The average level of the sea over a long period or the average level which would exist in the absence of tides.

Storm surge (http: / /en.wikipedia.orq /wiki /Storm surge) A storm surge is an offshore rise of water associated with a low pressure weather system, typically a tropical cyclone. Storm surge is caused primarily by high winds pushing on the ocean's surface. The wind causes the water to pile up higher than the ordinary sea level. Low pressure at the center of a weather system also has a small secondary effect, as can the bathymetry of the body of water. It is this combined effect of low pressure and

[SOPAC Miscellaneous Report 654 - Pearce] [38]

persistent wind over a shallow water body which is the most common cause of storm surge flooding problems. The term "storm surge" in casual (non- scientific) use is storm tide; that is, it refers to the rise of water associated with the storm, plus tide, wave run -up, and freshwater flooding. When referencing storm surge height, it is important to clarify the usage, as well as the reference point. NHC tropical storm reports reference storm surge as water height above normal astronomical tide level, and storm tide as water height above mean sea level.

In areas where there is a significant difference between low tide and high tide, storm surges are particularly damaging when they occur at the time of a high tide. In these cases, this increases the difficulty of predicting the magnitude of a storm surge since it requires weather forecasts to be accurate to within a few hours. The most extreme storm surge events occur as a result of extreme weather systems, such as tropical cyclones. Factors that determine the surge heights for landfalling tropical cyclones include the speed, intensity, size of the radius of maximum winds (RMW), radius of the wind fields, angle of the track relative to the coastline, the physical characteristics of the coastline and the bathymetry of the water offshore.

tTn, Storm tide Surge ,s f 2n.Normal high tide Mean sea level

Figure Al -4: Storm surge ( http: / /en. wikipedia.org /wiki /Storm_surge)

Sieches (Pugh 2004) Tide gauge records, particularly those from islands and places linked to oceans by narrow continental shelfs, often show high- frequency oscillations superimposed on the normal tidal changes of sea -level. These oscillations, called seiches, are due to local resonant oscillations of the harbours and coastal areas. The period depends on the horizontal dimensions and depth of water in the harbour. There are a number of triggers for seiching such as gravity waves, winds, atmospheric pressure disturbances and seismic activity. When the energy for sieching comes from external wave sources e.g. a tsunami, the size of the entrance to an oscillating basin is critical.

Shoaling As a tsunami leaves the deep water of the open -ocean and travels into the shallower water near the coast, it transforms. A tsunami travels at a speed that is related to the water depth - hence, as the water depth decreases, the tsunami slows. The tsunami's energy flux, which is dependent on both its wave speed and wave height, remains nearly constant. Consequently, as the tsunami's speed diminishes, its height grows. This is called shoaling. Because of this shoaling effect, a tsunami that is unnoticeable at sea, may grow to be several metres or more in height near the coast.

The increase of the tsunami's wave height as it enters shallow water is given by:

where hs and hd are wave heights in shallow and deep water and HS and Ha are the depths of the shallow and deep water. So a tsunami with a height of 1 m in the open ocean where the water depth is 4000m would have a wave height of 4 to 5 m in water of depth 10 m.

[SOPAC Miscellaneous Report 654 - Pearce] [39]

Just like other water waves, tsunami begin to lose energy as they rush onshore - part of the wave energy is reflected offshore [and in the case of an atoll, around the island], while the shoreward -propagating wave energy is dissipated through bottom friction and turbulence. Despite these losses, tsunami can still reach the coast with tremendous amounts of energy. Depending on whether the first part of the tsunami to reach the shore is a crest or a trough, it may appear as a rapidly rising or falling tide. Local bathymetry may also cause the tsunami to appear as a series of breaking waves.

Tsunami A tsunami is a series of ocean waves with very long wavelengths(typically hundreds of kilometres) caused by large -scale disturbances of the ocean, such as:

earthquakes

landslide

volcanic eruptions

explosions

meteorites

These disturbances can either be from below (e.g. underwater earthquakes with large vertical displacements, submarine landslides) or from above (e.g. meteorite impacts).

Tsunami is a Japanese word with the English translation: "harbour wave ". In the past, tsunami have been referred to as "tidal waves" or "seismic sea waves ". The term "tidal wave" is misleading; even though a tsunami's impact upon a coastline is dependent upon the tidal level at the time a tsunami strikes, tsunami are unrelated to the tides. (Tides result from the gravitational influences of the moon, sun, and planets.) The term "seismic sea wave" is also misleading. "Seismic" implies an earthquake -related generation mechanism, but a tsunami can also be caused by a non -seismic event, such as a landslide or meteorite impact.

Tsunami are also often confused with stormsurges,even though they are quite different phenomena. A storm surge is a rapid rise in coastal sea -level caused by a significant meteorological event - these are often associated with tropical cyclones.

TsunamiTravelTimes Tsunami can have wavelengths ranging from 10 to 500 km and wave periods of up to an hour. As a result of their long wavelengths, tsunami act as shallow -water waves. A wave becomes a shallow -water wave when the wavelength is very large compared to the water depth. Shallow -water waves move at a speed, c, that is dependent upon the water depth and is given by the formula:

where g is the acceleration due to gravity (= 9.8 m /s2) and H is the depth of water (m).

As the travel times are dependant on depth of the water [H] rather than magnitude of the earthquake, scenario based traveltimesto any location can be pre- computed for any earthquake tsunami source.

In the deep ocean, the typical water depth is around 4000 m, so a tsunami will therefore travel at around 200 m /s, or more than 700 km /hr.

For tsunami that are generated by underwater earthquakes, the amplitude (i.e.wave height) of the tsunami is determined by the amount by which the sea -floor is displaced.

[SOPAC Miscellaneous Report 654 - Pearce] [40]

Similarly, the wavelength and period of the tsunami are determined by the size and shape of the underwater disturbance.

As well as traveling at high speeds, tsunami can also travel large distances with limited energy losses. As the tsunami propagates across the ocean, the wave crests can undergo refraction (bending), which is caused by segments of the wave moving at different speeds as the water depth along the wave crest varies.

Types of waves (http: / /amath.colorado.edu /courses /4380 /All /ii43.pdf) There are a number of types of wave with a range of causes, physical mechanisms, periods, velocity and regions of influence affecting the oceans affecting the oceans and therefore the tide gauge. These are shown in Table Al -1.

Al -1: A number of wave types that can be found in lakes and oceans.

Wave type Cause Physical mechanismPeriod Velocity Region influenced Sound Sea life, ships Compressibility 10 -' - 10-' s 1.52 km/s Interior Capillary ripplesWind Surface tension < 10 -' s 25 -50 cm/s Surface Wind waves andWind Gravity 1 -25 s 2 -40 ni's Surface swell Sieches Earthquakes, Gravity. resonance minutes to standing waves Interior and surface of storms hours large lakes Storm surges Low pressure Gravity and earth rotation1 - 10 h -100 uils Coastal areas Tsunami Earthquakes, Gravity 10 min - 2 h < 800 kinlh Interior; on surface at slides shores Internal waves Stratification Gravity and density 2 min - 10 h < 5 mÌs Layer of sharp density instabilities, tides stratifications change Tides Moon and sun External gravity fields 12 - 24 h 1700 hull: h: Interior; on surface at bores a few km/h shores (bores) PIanetary wavesEarth rotation Gravity - 100 days 1 -10 knn.'h Interior

Tidal heights The height of the tide, in metres, is reckoned from the port datum (lowest astronomical tide (LAT) datum).

Tidal range variation: springs and neaps (http: / /en.wikipedia.org /wiki /Tide) The semidiurnal tidal range (the difference in height between high and low tides over about a half day) varies in a two -week or fortnightly cycle. Around new and full moon when the Sun, Moon and Earth form a line the tidal forces due to the Sun reinforce those of the Moon. The tide's range is then maximum: this is called the spring tide, or just springs and is derived not from the season of spring but rather from the verb meaning "to jump" or "to leap up ". When the Moon is at first quarter or third quarter, the Sun and Moon are separated by 90 °when viewed from the earth, and the forces due to the Sun partially cancel those of the Moon. At these points in the lunar cycle, the tide's range is minimum: this is called the neap tide, or neaps. Spring tides result in high waters that are higher than average, low waters that are lower than average, slack water time that is shorter than average and stronger tidal currents than average. Neaps result in less extreme tidal conditions. There is about a seven day interval between springs and neaps.

The changing distance of the Moon from the Earth also affects tide heights. When the Moon is at perigee the range is increased and when it is at apogee the range is reduced. Every 71/2 lunations, perigee coincides with either a new or full moon causing perigean tides with the largest tidal range. If a storm [or tsunami] happens to be moving onshore at this time, the consequences (in the form of property damage, etc.) can be especially severe.

[SOPAC Miscellaneous Report 654 - Pearce] [41]

Tsunami run -up (http: / /walrus.wr.usgs.gov /tsunami /basics.html). As the tsunami wave travels from the deep- water, continental slope region to the near - shore region, tsunami run -up occurs. Run -up is a measurement of the height of the water onshore observed above a reference sea level. Contrary to many artistic images of tsunami, most tsunami do not result in giant breaking waves (like normal surf waves at the beach that curl over as they approach shore). Rather, they come in much like very strong and very fast tides (i.e., a rapid, local rise in sea level). Much of the damage inflicted by tsunami is caused by strong currents and floating debris. The small number of tsunami that do break often form vertical walls of turbulent water called bores. Tsunami will often travel much farther inland than normal waves.

At a gauge reference sea level is the predicted tide height. Without a gauge it is often the MHW mark or MSL. Tsunami trace

Inundation height Runup height

Sea level at the event

Figure Al -5: Definitions of inundation and run -up height (Tornita et al. 2007).

Volcanic sources of tsunami Tsunami can be generated from other processes such as volcanic eruption, volcanic collapse and submarine landslide. The latter are often triggered by earthquakes and are commonly attributed to the earthquake. Steep sloped bathymetry on volcanic and other islands and submarine volcanoes may have the potential to slump or collapse and depending of the size of such collapses these events may cause local tsunami if debris is dumped into the sea.

4. Lateral blast

1. Original summit of volcano

2. Volcano collapses 5. Fast-moving debris avalanche crashes into sea / 6. Tsunamiforms 5 7. Wavetravelsout 3. Magma body is unroofed to distant coastlines

24,09!418 Figure Al -6: Tsunami generation process from a volcanic collapse (IAVCEI Workshop on Ulawun Decade Volcano, 1998).

[SOPAC Miscellaneous Report 654 - Pearce] [42]

Avalanche amphitheatre

Debris avalanche deposit

Rt `,O9Iib

ct ¡f,f 2b

Figure Al -7: Where debris collapses from an existing avalanche amphitheatre into the sea, it can generate a local tsunami (IAVCEI Workshop on Ulawun Decade Volcano, 1998).

Wave length The mean horizontal distance between successive crests (or troughs) of a wave pattern.

Wave period The average time interval between passages of successive crests (or troughs) of waves. Wave height Generally taken as the height difference between the wave crest and the preceding trough.

Wave amplitude Generally taken as the height above mean of wave, approximately half wave height.

[SOPAC Miscellaneous Report 654 - Pearce] [43]

Further information on tsunami

More information can be found at the following web sites:

General information International Tsunami Information Center Welcome to tsunami! Tsunami database (U.S. National Geophysical Data Center [NGDC])

Tsunami warning centres and hazard mitigation International Coordination Group for the Tsunami Warning System in the Pacific Pacific Tsunami Warning Center West Coast and Alaska Tsunami Warning Center U.S. National Tsunami Hazard Mitigation Program

Earthquake information Geoscience Australia U.S. National Earthquake Information Centre European- Mediterranean Seismological Centre

The Indian Ocean tsunami of Dec. 26th 2004 Scientific Background (from Columbia University)

Tsunami research Tsunami Research Center (University of Southern California) Tsunami Research Program (Pacific Marine Environmental Laboratory)

[SOPAC Miscellaneous Report 654 - Pearce] [44]

APPENDIX 2

Historical Tsunami Events Affecting Solomon Islands

a. Previous Tsunami that have been recorded in Solomon Islands

Extracts from National Geophysical Data Centre (NGDC), Tsunami Inundation Database show the highest recorded tsunami events in the Solomon Islands were: 10.5m at Beaufort Bay, on south west coast of Guadalcanal in 1939, 10m at Ghizo in 2007 and 9m at San Cristobal Island in 1931. These were all from near by Solomons Trench sources. One event was recorded from a regional source in Vanuatu on the New Hebrides Trench in 2007. There are very few recorded run -ups from distant (ocean -wide) sources. Those recorded were from Russia in 1952 and 2006 with both less than lm.

Table A2 -1 (a) & (b): Extracts from National Geophysical Data Centre (NGDC), Tsunami Inundation Database (a) Source generating run -up event (b) location of run -up.

(a) Tsunami Events where Runup Country = SOLOMON ISLANDS

View parameter descriptions and access statistical information by clicking on column headings.

For additional information about the tsunami, runups, associated earthquake or volcanic eruption, click on the links in the Addl Info, Num. of Runups, Earthquake Mag,or Volcans

TsunamiCause Date Tsunami SourceLocation Earth - Val- Year Mo Liv Fir Mn SecVal CodeQuake MancaioAddi Tsu Info Country Name Latitude Longitude 1857 4 17 4 4 8.0 PAPUA NEW GUINEA (BISMARCK SEA -5.500 147.000

1906 9 14 16 418,0 4 1 8_4 PAPUA NEW GUINEA [SOLOMON SEA I -7.000.1 149.000 e 1931 10 3.191313,0 4 1 7_9 ISOLOMON ISLANDS ;SAN CRISTOBAL ISLAND I -20.506r 61.750 1 2 3 1 1939 30 18 27,0 7.8 IPAPUA NEW GUINEA IBOUGAENVILLE ISLAND I -co6.S 155.500 1939 4 30 2 5530.0. 3 1 8_1 ISOLOMON ISLANDS SOLOMON ISLANDS l0.500 I58.500

1952. 11 4 15 58 1 4 1 1_ 9_0 IfìUSSLA KAMCNATKA ... I52.750 159.500

1955 9 8 3 271 16.01 3 I i 6_5 IPAPUA NEW GUINEA ;SOLOMON SEA -6.900 155.700 1957 11 [SOLOMONISLANDS ISOLOMON ISLANDS 1959 B 17 21 4140.01 7_3 ISOLOMON ISLANDS SOLOMON ISLANDS -7.500 156.000

1961; 3 18 1 2 I 0 ISOLOMON ISLANDS ISOLOMON ISLANDS 19511-81 1 5 39 53.21 6_6 ISOLOMON ISLANDS [SOLOMON SEA -9.900 166.590 1966 15' 0. 7.6 [SOLOMON ISLANDS ISOLOMONISLANDS -18.308 168:880

. 1966171' 28 1 1 O ISOLOMON ISLANDS IMOHAWK SAY, SANTA CRUZ ISLANDS 116.000 168.000

I 1 SOLOMON ISLANDS SAIVFACRUZ ISLANDS I 1966r12'31'18123.3.914 7.5 -11.800 166.500

196172: 31'22ls.14.0 1! I 1 7_3 [SOLOMON ISLANDS ;SANTA CRUZ ISLANDS -11.30U 164.880

I 1971! 7 14 51.1.! 29.1' 4 1 7.4 IPAPUA NEW GUINEA 'BISMARCK. SEA -5.500 153.900 1971 7 25 1 23 21.3 4 1 7 -9 'PAPUA NEW GUINEA BISMARCK SEA -ß.900 153.206 11971; 9 6 20 4 Val SOLOMON ISLANDS 1TENAKULA, SANTA CRUZ -10.380 165.800

1972170. 9 4 I Vol IPAPUA NEW GUINEA ;RITTER ISLAND, PAPUA NEW GUINEA -5.520 148.121

1 1974r-1 31 23 5.3 4 1 7_o [SOLOMON ISLANDS ISOLOMON ISLANDS -7.500 155.965 1974[-2 I37.2 33.11 4- 1 7.1 ;SOLOMON ISLANDS SOLOMON ISLANDS - 7.400 155.600

7977741 20123r131 10.41 4 I 1 6_8 ISOLOMON ISLANDS ISOLOMON ISLANDS -9.828 163.323

1477r 40-1t21 50.5 I 1 7_6 ISOLOMON ISLANDS ISOLOMON ISLANDS -9.890 160.348 1987 15.11 1 6.0 [SOLOMON ISLANDS iSOLOMON ISLANDS -10.707 162.325

1 I988r 701711 38 26.Y 1 7.6 ISOLOMON ISLANDS SOLOMON ISLANDS 0.366 160.819 79911-21-9 1.8 58.317E! I 1 7.0 So LOMON ISLANDS SOLOMON ISLANDS 9.929. 159.139

1991 f0 15 5112.71! I 1 7_3 [SOLOMON ISLANDS SOLOMON ISLANDS -9.098 158.440

1 19921 5 2711 131 38.81.' 1 7.1 [SOLOMON ISLANDS SANTA CRUZ ISLANDS -11.122 165.239 1997r 41.21- 26.4..4 1 7.7 ISOLOMON ISLANDS SANTA CRUZ I8. VANUATU -12.584 I66.676 2800 1.7!7541567 4 1 8.0 IPAPUA NEW GUINEA NEW IRELAND -3.988I52.169 2003 0IL17,13'6.0 4 1 7.3 ISOLOMON ISLANDS SOLOMON ISLANDS -10.491 160.779 2006 E1 I11-14. 13.5 4 1 8.3 [RUSS A S. KURIL ISLANDS 46.592 153.266 2i1307151-01-401 1.6 4 1 7 -1 VANUA U ¡VANUATU ISLANDS - 29.517 169.357

1 20071 4 0 9:16.3 4 1 8.1 SOLOMON ISLANDS ISOLOMON ISLANDS -8.466 157.044

[SOPAC Miscellaneous Report 654 - Pearce] [45]

(b)

Tsunami RUnups where Runup Country = SOLOMON ISLANDS

Viewparameter des r pbOns and access statistical information by chicking on column headings.

For additional Information about the tsunamigenic earthquake, tsunami runup, or source event e dick on the links in the Cause EQ Nag, AMR Src Info or Addl Runup Into columns.

Tsunami Source Mal Info Tsunami Runup Location TsunamiRunup Measurements Tt Bate Tsu Doubt- Travel Time Max Max Deaths Cau Tsu EQVol- Tsu tul Distance WaterInundation 1st Voir Mtry Hr Min Sec Val Code Sm Meg cano Runup Runup Country Name Latitude Longitudefrom SourceHrs Mill Height Distance Type Per MtnMum De r1857 17 4 4 * 8.0 s SOLOMON ISLANDS W. NEW BRITAIN '1986 15,16: 4 184 1 0 1.4 r SOLOMON ISLANDS VITIAZ STRAIT 1.50 r 1931 1 I 131 4 1 SOLOMON ISLANDS ;IRA KIRA, SOLOMON ISLANDS 31191 131 * 7.9 .10.4501 161.930: 29,5 Í 2.00

1931 1E 3 19 13 13x4 1 * 7.9 o (SOLOMON ISLANDS (PORT MARY, SOLOMON ISLANDS 1 3.00 F a I 1 I 1931 1 E9 131 3E4 1 °17.9 (SOLOMON ISLANDS í,SAN CRISTOBAL ISLAND 1 -10.6881 161.750I- 11.1 r9.00 F 50 1 1939 130 21781 z71 1 ' 7.8 SOLOMON ISLANDS AIS1. 2.oó c 1939 130 1 .1 131. (SOLOMON ISLANDS IBEAUFORTBAY,GUADALCANAL 1 .151.0 E 1 -9.8091 í6o.0001 181.7 1 10.50 12 1 1939 30Er .51013 1 1 1 8.1 v ISOLOMON ISLANDS IIRUSSELL I. 1 -9.0501 159:2001 178.5 1952 1179 I.-s8 1 .T nr 1 9.6 ISQLOMaNISLANDS 15í455I IS. .90

1 1 1955 8 1 32Tí16x3 1 ''' 1SOLOMON ISLANDS FAURD I. 1 -6.9381 156.8801 42.1 w 1 1 1957 E2 1 1 rE° ',SOLOMON ISLANDS 1AFFO, NW MALAITA -9.0011 161.000 2.70 1957.1 SOLOMON ISLANDS 1FAUA00, NW MALARA -8.570 160.720 2J0 11959.1 z2r Qa0 r4 rni Z3 SOLOMON ISLANDS IVELLA LIVELLI I. -7.75D 156.5801 69.7 1,10 119611 rf8 r2 1 SOLOMON ISLANDS GUADALCANAL 1-3.60

19611-r38 r2 0 SOLOMON ISLANDS (SAN CRISTOBAL ISLAND 1 -10.6011 161.750 1 3.60 119fi11-775139 53:219r* 6.6 SOLOMON ISLANDS 5. COAST 80

1 19661- 51-0 1 1 7.6 SOLOMON ISLANDS POINT CRUZ ;HONIARA) -9.4711 159.9581 131.1 1 .11 1 119661 1151 01 591 8r3 1 7.6 SOLOMON ISLANDS S.o.N CRISTOBAL ISLAND -10.6001. 161.7511 109.1 19fifi'173 (SOLOMON ISLANDS MOHAW K BAY, SANTA CRUZ ISLANDS -10.000' 166.2001 197.2

1 1 1 19661 3I 181 231 3.9E4 7.5 (SOLOMON ISLANDS 1VANIKOLO (VANIKORO), SANTA CRUZ IS. -11.617 166.9671 54.8 1 2.80

1 29661111151M r9 1 7.3 (SOLOMON ISLANDS 'VANIKOLO (VANIKORO), SANTA CRUZ IS. 111.617 166.967: 3318 1 1.50 79711 1141 61 11129.1 4 9 rr.9 SOLOMON ISLANDS KUNUA

119711-r261-123 22.3E4 1 .1Th.9 (SOLOMON ISLANDS (NORTH SOLOMON SEA 1 3.00 119711 16'10- 6 t I Vol (SOLOMON ISLANDS (NEO VILLAGE, TRAVANION ISLAND I97217.173 (SOLOMON ISLANDS 1RIAZ STRAIT

119741 '312330'5.3, 4 ' 1 *'7.0 (SOLOMON ISLANDS 1kOROVU,SHORTLAND ISLAND -7.1091 155.6001 55.5 1.50 1 19741 1 3 12 33.14 1 v 7.1 IsOLOMON ISLANDS 1CHOTSEHL -7.0131 157.000' 158.4 4.50 14. 1 3 12 33.14 1 *7.1 (SOLOMON ISLANDS (HONIARA, GUADALCANAL -9.433 159.9501 529.3 15 2

1977 20 2313 10.4 4 1 6.8 SOLOMON ISLANDS 1HONIARA, GUADALCANAL -9.4331 159.9501 372.5 1 .15 2 1977 20 2313' 10.41 4 1 6.8 SOLOMON ISLANDS 1R,ENNELL -11.5101 160.0001 408.0

, 1977 20 2392'50.51 4 ', 1 ;7.6 (SOLOMON ISLANDS IRENNELL -11.508 160.000 183.1 1987', 18 14 3.15.1 Ì II* 16.6.D (SOLOMON ISLANDS (SOLOMON ISLANDS -10.707 162.326 10 4 1 11988( 38,26.114 (SOLOMON ISLANDS NONDARA, GUADALCANAL -9.4331 159.950 140.8 1 .09 r 2 1 19881 1101 41 38126.1 (SOLOMON ISLANDS (SAN CRISTOBAL ISLAND -10.610 I.61.750 105.1 I 110.00 I- 1 '-41-i 1911-19561 18 59.3r49rr 7.6 (SOLOMON ISLANDS (HONIARA, GUADALCANAL -1433 159.9501-104.5IC:i 181:1.4 91 18

1 -9.4331 1 2 1 299111 14 IS58 12.7E4 73 (SOLOMON ISLANDS (HONIARA, GUADALCANAL 159.950 170.1 1 .15 11992 1 7.1 SOLOMON.ISLANDS !SANTA CRUZ ISLANDS -10.7511 165.920 85.1 19971 21112r 26.4r4 9 SOLOMON ISLANDS 1CRGWDY HEAD IS., SANTA CRUZ ISLANDS -11750 r 165.920 220.0 1 199721 121 2 26nr9 1 7.7 (SOLOMON ISLANDS (LORD HOWE ISLAND, SANTACRUZISLAND -10.7501 165.920 220.0

1 1997 1-21 121 2 26.414 1 1"7.7 (SOLOMON ISLANDS 1i0WEED HEAD IS., SANTA CRUZ ISLANDS -10.7501 165.920 220.0 2000rn76754 56.7r49f* e6 (SOLOMON ISLANDS ICi ZO ISLAND -8.070 156.8005.0 80 1 1200011161 4 s4 Se.7r4 r+sG (SOLOMON ISLANDS ÏORO -8.2201 157.220 731.0 1 1.00 03201 931 614 1 7.3 SOLOMON ISLANDS (SAN CRISTOBAL ISLAND -10.6811 161.750 107.8 1 757 13.59r* 6.3 (SOLOMON ISLANDS [HONIARA, GUADALCANAL -9.433' 159.950 6266.8 :.1.4 9 1 1 2 20071-1510 1.fir4 zi (SOLOMON ISLANDS 1HONIARA, GUADALCANAL 1 -9.4331 159.950 1501.4 11471 .52 rß

0071 56.3E9 1 rr9I SOLOMON ISLANDS 11CHDSSE1IL ISLAND, NEW GEORGIA GROUP 1.0131 157.011 153.2 1 1 . DMON ISLANDS LGIZO ISLAND, NEW GEORGIA GROUP -0.567 156.800 51.3 r20D7r-ri73 s9156.31a 9 6.1 I 9 12007E r 112639 s6s1 B.2 9 'SOLOMON ISLANDS 11-EONARA, GUADALCANAL ISLAND 'I -9.4331 159.950 337.11 PI 451 .21 1 2 20071 1 11731 39156.31 * B.1 'SOLOMON ISLANDS 1KOLOMBANGARA IS, NEW GEORGIA GROUP -8.0001 157.167 52.9 9 '20071-112D39 56.3M9'* 131. SOLOMON ISLANDS IMUNDA, NEW GEORGIA ISLAND 18.3171 157.250 27.7 1 1

-I 12007 1-1 l E20139.1 56.31 4 1Th B.1 'SOLOMON ISLANDS WIG, NEW GEORGIA ISLAND -8.2171 157.217 33.1 1 1

1 2007E E1120 a9 E55.3 f 1 8.1 * 'SOLOMON ISLANDS IRANONGGA ISLAND, NEW GEORGIA GROUP 'I -8.0671 155.533 71.2 1 1

1 1 1 1 120071 39155.3 I* 19.1 'SOLOMON ISLANDS [SANTA ISABEL ISLAND -8.0431 159.454 269.3 1 1 1-2o0717l2039 s6.3ra * 131_ SOLOMON ISLANDS 1SHORTLANDS ISLANDS, W PROVINCE -6.917 155.883 214.1 9

'SOLOMON ISLANDS 1511110 ISLAND, NEW GEORGIA GROUP 156.550 57.1 1 1 .10071-1 16.1 1 -8.2831 z1D7r112D9 LW' f 1 rf r9.1 'SOLOMON ISLANDS 'VELLA LAMELLA FS, NEW GEORGIA GROUP 50 156.667 89.2 9

[SOPAC Miscellaneous Report 654 - Pearce] [46]

2 Recent PTWC Warnings

(i) Solomon Islands 2 April 2007 Tsunami

USGS

rEN M8.1 Solomon Islands Earthquake of 1 April 2007 CSN

Tam Swung PpiceirmrlAegrori i-'amm9®®o®®®®o®®mm

r:,....,....w..°,.,..-..._.....,..

SYiu,,,r H rsl

rill ' M Firrirc FmrltModei rç.=ME-2;:--` II

Ienin ' ..-' 1 EPLANAIIqi ®a rl

Figure A2 -1: USGS Poster of Solomon Islands 2 April 2007 Earthquake (http: / /earthquake.usgs.gov).

TSUNAMI POTENTIAL (RELATIVE TO EARTHQUAKE DISLOCATION) Estimated Tsunami Travel Time (Hours) 12BE 130E ICE 150E 1500 170E 180

oo' 120' 193' lao' 210' Zao' no' ISOM

ao'

o'

lax 120' 150' 210' 240 270' Planed 71 Pp 2,7- 22.1.7G

Figure A2 -2: Travel times map and model scenario for Solomon's tsunami 2 April 2007.

The Solomon Trench earthquake of 2 April 2007 is described in the USGS poster at Figure A2- 1. The model scenario and forecast travel times for the tsunami are shown at Figure A2 -2. The Solomon Islands warning points used by the PTWC are at Table A2 -2 and the PTWC Warnings for this event are below. During the PTWC expanding warning /watch phase, any of the locations below is within 3 hour (warning) or 6 hours (watch) travel time for the predicted

[SOPAC Miscellaneous Report 654 - Pearce] [47] expanding tsunami, all the Solomon Islands will be included in the warning /watch process. Travel times are then provided for all Solomon Islands locations whether in warning or watch range. Note that the initial estimate of magnitude was 7.8 and a regional (see A2 4(i)) warning covering 1000 km / 3 hours travel time was issued.In the second warning the estimate of magnitude was increased to 8.1 and an expanding warning /watch phase was initiated for potentially Ocean -wide tsunami. The forecast travel time to Honiara from source was 40 minutes from the earthquake, 25 minutes after first PTWC bulletin issued.

Table A2 -2: Solomon Islands warning locations used by PTWC.

MUNDA 8.4S 157.2E Rendova Island FALAMAE 7.4S 155.6E Mono Island PANGGOE 6.9S 157.2E Choiseul Island HONIARA 9.3S 160.0E Guadalcanal GHATERE 7.8S 159.2E Santa Isabel Island AUKI 8.8S 160.6E Malaita Island KIRAKIRA 10.4S 161.9E San Cristobal Island

Dal NfIKUMANU IS VILNA /LAU IS TAUU IS. PAPUA IePetificIÑ!tl Na, NEW GUINEA SOUTH Bake ONTONG ., l YATOLL S nelNeee W9.1 Bougainville PACIFIC NAURU Raw ntl NS) OCEAN KIRIBATI PARIA r EM! GOURE\ SOLOMON e' Choiseuf 1 N iSLANUS TUYALU l WESTERN F.-T 1 Mr Santa \ IU s; vexa \ 1b! MALAITA VANUATU'- FUI Lere11N. #phme.nge.e Oei WESTERN "'"i,Bim NU cm, Géóqie l / AUSTRALIA Cel ma w>r 51eWenl TONGA F+zl NEW GEORGIA /II Yen9- I s ISLANDS Rena . FLOa41A -Ç I R SELL is 15LAN 5 1 Pa.a.e . ', Malaria e)-'- LP i1eni/ 1"1"'..4.aska Guadalcanaf .. `Wawa CENTRAL : Lira near GLAND ie9y 9 Solomon Sea San EASTERN Nendá Cristobal - m G- Rossel c` Island Ballone I. I./tepee Ñ Rennelf Yenikalo ÿ Artute Is. 'regale 0 N . Peaks

Solomon Islands lsueasTORRES --- Lino of separation (not a formal international Ma. Lew boundary or territorial limit) Coral Se. Vanua Lava BANKS ISLANDS - -- District boundary SanteMarie ,MOM * National capital VANUATU

o District capital Espiritu Santo Aune Meéwa Lapwide Penrecest 50 1001$0 200 I(IOaters Io 6 5Q lÓ0 150 200 Miles Amborm Malakula Ear ase504-633(645714) 4-81

Figure A2 -3: Locations of PTWC warning reference points in Solomon Islands based on Table A2 -2.

[SOPAC Miscellaneous Report 654 - Pearce] [48]

Example 1: PTWC Bulletin No 1

TSUNAMI BULLETIN NUMBER 001

PACIFIC TSUNAMI WARNING CENTER /NOAA/NWS ISSUED AT 2055Z 01 APR 2007

THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.

... A TSUNAMI WARNING IS IN EFFECT ...

A TSUNAMI WARNING IS IN EFFECT FOR

SOLOMON IS. / PAPUA NEW GUINEA

FOR ALL OTHER PACIFIC AREAS, THIS MESSAGE IS AN ADVISORY ONLY.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME - 2040Z 01 APR 2007 COORDINATES -8.6 SOUTH 157.2 EAST LOCATION- SOLOMON ISLANDS MAGNITUDE - 7.8

EVALUATION

IT IS NOT KNOWN THAT A TSUNAMI WAS GENERATED. THIS WARNING IS BASED ONLY ON THE EARTHQUAKE EVALUATION. AN EARTHQUAKE OF THIS SIZE HAS THE POTENTIAL TO GENERATE A DESTRUCTIVE TSUNAMI THAT CAN STRIKE COASTLINES IN THE REGION NEAR THE EPICENTER WITHIN MINUTES TO HOURS. AUTHORITIES IN THE REGION SHOULD TAKE APPROPRIATE ACTION IN RESPONSE TO THIS POSSIBILITY. THIS CENTER WILL MONITOR SEA LEVEL GAUGES NEAREST THE REGION AND REPORT IF ANY TSUNAMI WAVE ACTIVITY IS OBSERVED. THE WARNING WILL NOT EXPAND TO OTHER AREAS OF THE PACIFIC UNLESS ADDITIONAL DATA ARE RECEIVED TO WARRANT SUCH AN EXPANSION.

ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES. ACTUAL ARRIVAL TIMES MAY DIFFER AND THE INITIAL WAVE MAY NOT BE THE LARGEST. THE TIME BETWEEN SUCCESSIVE TSUNAMI WAVES CAN BE FIVE MINUTES TO ONE HOUR.

LOCATION COORDINATES ARRIVAL TIME

SOLOMON IS. MUNDA 8.4S157.2E 2039Z01APR FALAMAE 7.4S155.6E 2059Z01APR PANGGOE 7.0S157.5E 2108Z01APR GHATERE 7.5S159.0E 2117Z01APR HONIARA 9.0S160.0E 2120Z01APR AUKI 8.8S160.6E 2130Z01APR KIRAKIRA 10.05162.0E 2136Z01APR PAPUA NEW GUINE AMUN 6.0S154.7E 2116Z01APR KIETA 6.1S155.6E 2123Z01APR RABAUL 4.2S152.3E 2145Z01APR LAE 6.8S147.0E 2214Z01APR KAVIENG 2.5S150.7E 2216Z01APR MADANG 5.2S145.8E 2241Z01APR MANUS IS. 2.0S147.5E 2250Z01APR PORT MORESBY 9.3S146.9E 2252Z01APR WEWAK 3.5S144.0E 2319Z01APR VANIMO 2.6S141.3E 2346Z01APR

BULLETINS WILL BE ISSUED HOURLY OR SOONER IF CONDITIONS WARRANT. THE TSUNAMI WARNING WILL REMAIN IN EFFECT UNTIL FURTHER NOTICE.

THE JAPAN METEOROLOGICAL AGENCY MAY ALSO ISSUE TSUNAMI MESSAGES FOR THIS EVENT TO COUNTRIES IN THE NORTHWEST PACIFIC AND SOUTH CHINA SEA REGION. IN CASE OF CONFLICTING INFORMATION... THE MORE CONSERVATIVE INFORMATION SHOULD BE USED FOR SAFETY.

THE WEST COAST /ALASKA TSUNAMI WARNING CENTER WILL ISSUE BULLETINS FOR ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.

[SOPAC Miscellaneous Report 654 - Pearce] [49]

TSUNAMI BULLETIN NUMBER 002

PACIFIC TSUNAMI WARNING CENTER /NOAA/NWS ISSUED AT 2132Z 01 APR 2007

THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.

... A TSUNAMI WARNING AND WATCH ARE IN EFFECT ...

A TSUNAMI WARNING IS IN EFFECT FOR

SOLOMON IS. / PAPUA NEW GUINEA / VANUATU / NAURU / CHUUK / NEW CALEDONIA / POHNPEI / KOSRAE / AUSTRALIA / INDONESIA / TUVALU / KIRIBATI / MARSHALL IS.

A TSUNAMI WATCH IS IN EFFECT FOR

GUAM / FIJI / N. MARIANAS / YAP / HOWLAND -BAKER / WALLIS- FUTUNA / BELAU / TOKELAU / KERMADEC IS / SAMOA / NEW ZEALAND / MARCUS IS. / WAKE IS. / AMERICAN SAMOA / TONGA / NIUE / COOK ISLANDS / PHILIPPINES / JARVIS IS. / PALMYRA IS. / JOHNSTON IS. !JAPAN

FOR ALL OTHER PACIFIC AREAS, THIS MESSAGE IS AN ADVISORY ONLY.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME - 2040Z 01 APR 2007 COORDINATES -8.6 SOUTH 157.2 EAST LOCATION - SOLOMON ISLANDS MAGNITUDE -8.1

EVALUATION

IT IS NOT KNOWN THAT A TSUNAMI WAS GENERATED. THIS WARNING IS BASED ONLY ON THE EARTHQUAKE EVALUATION. AN EARTHQUAKE OF THIS SIZE HAS THE POTENTIAL TO GENERATE A DESTRUCTIVE TSUNAMI THAT CAN STRIKE COASTLINES NEAR THE EPICENTER WITHIN MINUTES AND MORE DISTANT COASTLINES WITHIN HOURS. AUTHORITIES SHOULD TAKE APPROPRIATE ACTION IN RESPONSE TO THIS POSSIBILITY. THIS CENTER WILL MONITOR SEA LEVEL DATA FROM GAUGES NEAR THE EARTHQUAKE TO DETERMINE IF A TSUNAMI WAS GENERATED AND ESTIMATE THE SEVERITY OF THE THREAT.

ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES. ACTUAL ARRIVAL TIMES MAY DIFFER AND THE INITIAL WAVE MAY NOT BE THE LARGEST. THE TIME BETWEEN SUCCESSIVE TSUNAMI WAVES CAN BE FIVE MINUTES TO ONE HOUR.

LOCATION COORDINATES ARRIVAL TIME

SOLOMON IS. MUNDA 8.4S157.2E 2039Z01APR FALAMAE 7.4S155.6E 2103Z01APR PANGGOE 6.9S157.2E 2120Z01APR HONIARA 9.3S160.0E 2121Z01APR GHATERE 7.8S159.2E 2122Z01APR AUKI 8.8S160.6E 2134Z01APR KIRAKIRA 10.45161.9E 2140Z01APR PAPUA NEW GUINE AMUN 6.0S154.7E 2124Z01APR KIETA 6.1S155.6E 2133Z01APR RABAUL 4.2S152.3E 2145Z01APR LAE 6.8S147.0E 2218Z01APR KAVIENG 2.5S150.7E 2223Z01APR MADANG 5.2S146.0E 2241Z01APR PORT MORESBY 9.5S147.0E 2254Z01APR MANUS IS. 2.0S147.5E 2259Z01APR WEWAK 3.5S143.6E 2325Z01APR VANIMO 2.6S141.3E 2350Z01APR VANUATU ESPERITU SANTO 15.15167.3E 2236Z01APR ANATOM IS. 20.25169.9E 2322Z01APR NAURU NAURU 0.5S166.9E 2311201APR CHUUK CHUUK IS. 7.4N151.8E 2329Z01APR NEW CALEDONIA NOUMEA 22.35166.5E 2338Z01APR POHNPEI POHNPEI IS. 7.ON158.2E 2345Z01APR KOSRAE KOSRAE IS. 5.5N163.0E 2345Z01APR AUSTRALIA CAIRNS 16.75145.8E 2349Z01APR BRISBANE 27.25153.3E 0033Z02APR

[SOPAC Miscellaneous Report 654 - Pearce] [50]

SYDNEY 33.9S 151.4E 0114Z 02 APR GLADSTONE 23.8S 151.4E 0139Z 02 APR MACKAY 21.1S 149.3E 0144Z 02 APR HOBART 43.3S 147.6E 0245Z 02 APR INDONESIA JAYAPURA 2.4S 140.8E 2354Z 01 APR WARSA 0.6S 135.8E 0037Z 02 APR MANOKWARI 0.8S 134.2E 0056Z 02 APR

PATANI 0.4N 128.8E 0158Z 02 APR GEME 4.8N 126.8E 0202Z 02 APR MANADO 1.5N 124.8E 0242Z 02 APR TARAKAN 3.3N 117.6E 0400Z 02 APR SINGKAWANG 1.ON 108.8E 1240Z 02 APR PANGKALPINANG 2.OS 106.2E 1547Z 02 APR TUVALU FUNAFUTI IS. 7.9S 178.5E 2359Z 01 APR KIRIBATI TARAWA IS. 1.5N 173.0E 0007Z 02 APR KANTON IS. 2.8S 171.7W 0121Z 02 APR CHRISTMAS IS. 2.ON 157.5W 0325Z 02 APR MALDEN IS. 3.9S 154.9W 0336Z 02 APR FLINT IS. 11.4S 151.8W 0408Z 02 APR MARSHALL IS. KWAJALEIN 8.7N 167.7E 0022Z 02 APR MAJURO 7.1N 171.4E 0028Z 02 APR ENIWETOK 11.4N 162.3E 0037Z 02 APR GUAM GUAM 13.4N 144.7E 0035Z 02 APR FIJI SUVA 18.1S 178.4E 0038Z 02 APR N. MARIANAS SAIPAN 15.3N 145.8E 0041Z 02 APR YAP YAP IS. 9.5N 138.1E 0048Z 02 APR HOWLAND -BAKER HOWLAND IS. 0.6N 176.6W 0057Z 02 APR WALLIS -FUTUNA WALLIS IS. 13.2S 176.2W O100Z 02 APR BELAU MALAKAL 7.3N 134.5E 0103Z 02 APR TOKELAU NUKUNONU IS. 9.2S 171.8W 0119Z 02 APR KERMADEC IS RAOUL IS. 29.2S 177.9W 0131Z 02 APR SAMOA APIA 13.8S 171.8W 0135Z 02 APR NEW ZEALAND NORTH CAPE 34.4S 173.3E 0138Z 02 APR EAST CAPE 37.5S 178.5E 0214Z 02 APR AUCKLAND(W) 37.1S 174.2E 0238Z 02 APR GISBORNE 38.7S 178.0E 0247Z 02 APR MILFORD SOUND 44.5S 167.8E 0249Z 02 APR NEW PLYMOUTH 39.15 174.1E 0310Z 02 APR NAPIER 39.55 176.9E 0316Z 02 APR WESTPORT 41.85 171.2E 0332Z 02 APR AUCKLAND(E) 36.7S 175.0E 0332Z 02 APR WELLINGTON 41.5S 174.8E 0333Z 02 APR BLUFF 46.65 168.3E 0351Z 02 APR NELSON 41.3S 173.3E 0426Z 02 APR LYTTELTON 43.6S 172.7E 0439Z 02 APR DUNEDIN 45.9S 170.5E 0506Z 02 APR MARCUS IS. MARCUS IS. 24.3N 154.0E 0138Z 02 APR WAKE IS. WAKE IS. 19.3N 166.6E 0141Z 02 APR AMERICAN SAMOA PAGO PAGO 14.35 170.7W 0144Z 02 APR TONGA NUKUALOFA 21.0S 175.2W 0152Z 02 APR NIUE NIUE IS. 19.0S 170.0W 0209Z 02 APR COOK ISLANDS PUKAPUKA IS. 10.8S 165.9W 0212Z 02 APR PENRYN IS. 8.9S 157.8W 0316Z 02 APR RAROTONGA 21.2S 159.8W 0324Z 02 APR PHILIPPINES DAVAO 6.8N 125.7E 0215Z 02 APR LEGASPI 13.2N 124.0E 0248Z 02 APR ZAMBOANGA 7.ON 122.2E 0256Z 02 APR PALANAN 17.1N 122.6E 0307Z 02 APR LAOAG 18.2N 120.6E 0352Z 02 APR PUERTO PRINCESA 9.8N 119.0E 0404Z 02 APR SAN FERNANDO 16.6N 120.3E 0421Z 02 APR ILOILO 10.8N 122.8E 0438Z 02 APR MANILA 14.5N 120.8E 0517Z 02 APR JARVIS IS. JARVIS IS. 0.4S 160.1W 0256Z 02 APR PALMYRA IS. PALMYRA IS. 6.3N 162.4W 0300Z 02 APR JOHNSTON IS. JOHNSTON IS. 16.7N 169.5W 0308Z 02 APR JAPAN KATSUURA 35.1N 140.3E 0312Z 02 APR OKINAWA 26.2N 128.0E 0318Z 02 APR SHIMIZU 32.8N 132.8E 0359Z 02 APR KUSHIRO 42.8N 144.2E 0410Z 02 APR HACHINOHE 40.5N 141.8E 0415Z 02 APR

BULLETINS WILL BE ISSUED HOURLY OR SOONER IF CONDITIONS WARRANT. THE TSUNAMI WARNING AND WATCH WILL REMAIN IN EFFECT UNTIL FURTHER NOTICE.

[SOPAC Miscellaneous Report 654 - Pearce] [51]

TSUNAMI BULLETIN NUMBER 006

PACIFIC TSUNAMI WARNING CENTER /NOAA/NWS ISSUED AT 0158Z 02 APR 2007

THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.

NOTE: AREAS TO THE NORTH OF THE SOLOMON ISLANDS SHOULD NOT BE SIGNIFICANTLY AFFECTED

... A TSUNAMI WARNING AND WATCH ARE IN EFFECT ...

A TSUNAMI WARNING IS IN EFFECT FOR

SOLOMON IS. / PAPUA NEW GUINEA / VANUATU / NEW CALEDONIA / NORTHEASTERN AUSTRALIA / TUVALU / KIRIBATI / FIJI / KERMADEC IS / NEW ZEALAND

FOR ALL OTHER PACIFIC AREAS, THIS MESSAGE IS AN ADVISORY ONLY.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME - 2040Z 01 APR 2007 COORDINATES -8.6 SOUTH 157.2 EAST LOCATION- SOLOMON ISLANDS MAGNITUDE -8.1

MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY

GAUGE LOCATION LAT LON TIME AMPL PER

MANUS PG 2.0S147.4E 0040Z 0.09M= 0.3FT 40MIN VANUATU VU 17.85168.3E 0114Z 0.14M= 0.5FT 28MIN HONIARA SB 9.4S160.0E 2308Z 0.20M= 0.6FT 62MIN

LAT - LATITUDE (N= NORTH, S= SOUTH) LON - LONGITUDE (E =EAST, W =WEST) TIME - TIME OF THE MEASUREMENT (Z = UTC = GREENWICH TIME) AMPL - TSUNAMI AMPLITUDE MEASURED RELATIVE TO NORMAL SEA LEVEL. IT IS ...NOT... CREST -TO- TROUGH WAVE HEIGHT. IT IS ...NOT... CREST -TO- TROUGH WAVE HEIGHT. VALUES ARE GIVEN IN BOTH METERS (M) AND FEET (FT). PER - PERIOD OF TIME IN MINUTES(MIN) FROM ONE WAVE TO THE NEXT.

NOTE: PTWC HAS RECEIVED REPORTS OF TSUNAMI RELATED FATALITIES IN SOUTHEAST PAPUA NEW GUINEA AND THE SOLOMON ISLANDS.

EVALUATION

SEA LEVEL READINGS INDICATE A TSUNAMI WAS GENERATED. IT MAY HAVE BEEN DESTRUCTIVE ALONG COASTS NEAR THE EARTHQUAKE EPICENTER AND COULD ALSO BE A THREAT TO MORE DISTANT COASTS. AUTHORITIES SHOULD TAKE APPROPRIATE ACTION IN RESPONSE TO THIS POSSIBILITY. THIS CENTER WILL CONTINUE TO MONITOR SEA LEVEL DATA TO DETERMINE THE EXTENT AND SEVERITY OF THE THREAT.

FOR ALL AREAS - WHEN NO MAJOR WAVES ARE OBSERVED FOR TWO HOURS AFTER THE ESTIMATED TIME OF ARRIVAL OR DAMAGING WAVES HAVE NOT OCCURRED FOR AT LEAST TWO HOURS THEN LOCAL AUTHORITIES CAN ASSUME THE THREAT IS PASSED. DANGER TO BOATS AND COASTAL STRUCTURES CAN CONTINUE FOR SEVERAL HOURS DUE TO RAPID CURRENTS. AS LOCAL CONDITIONS CAN CAUSE A WIDE VARIATION IN TSUNAMI WAVE ACTION THE ALL CLEAR DETERMINATION MUST BE MADE BY LOCAL AUTHORITIES.

ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES. ACTUAL ARRIVAL TIMES MAY DIFFER AND THE INITIAL WAVE MAY NOT BE THE LARGEST. THE TIME BETWEEN SUCCESSIVE TSUNAMI WAVES CAN BE FIVE MINUTES TO ONE HOUR.

LOCATION COORDINATES ARRIVAL TIME

SOLOMONIS. MUNDA 8.4S157.2E 2039Z01APR FALAMAE 7.4S155.6E 2103Z01APR PANGGOE 6.9S157.2E 2120Z01APR HONIARA 9.3S160.0E 2121Z01APR GHATERE 7.8S159.2E 2122Z01APR AUKI 8.8S160.6E 2134Z01APR KIRAKIRA 10.45161.9E 2140Z01APR

[SOPAC Miscellaneous Report 654 - Pearce] [52]

PAPUA NEW GUINEAMUN 6.OS154.7E 2124201APR KIETA 6.1S155.6E 2133201APR RABAUL 4.2S152.3E 2145201APR LAE 6.8S147.0E 2218201APR KAVIENG 2.5S150.7E 2223201APR MADANG 5.2S146.0E 2241201APR PORT MORESBY 9.5S147.0E 2254201APR MANUS IS. 2.0S147.5E 2259201APR WEWAK 3.5S143.6E 2325201APR VANIMO 2.6S141.3E 2350201APR VANUATU ESPERITU SANTO 15.15167.3E 2236201APR ANATOM IS. 20.25169.9E 2322201APR NEW CALEDONIA NOUMEA 22.35166.5E 2338201APR AUSTRALIA CAIRNS 16.75145.8E 2349201APR BRISBANE 27.25153.3E 0033202APR SYDNEY 33.95151.4E 0114202APR GLADSTONE 23.85151.4E 0139202APR MACKAY 21.15149.3E 0144202APR HOBART 43.35147.6E 0245202APR TUVALU FUNAFUTI IS. 7.9S178.5E 2359201APR KIRIBATI TARAWA IS. 1.5N173.0E 0007202APR KANTON IS. 2.8S171.7W 0121202APR CHRISTMAS IS. 2.ON157.5W 0325202APR MALDEN IS. 3.9S154.9W 0336202APR FLINT IS. 11.45151.8W 0408202APR FIJI SUVA 18.15178.4E 0038202APR KERMADEC IS RAOUL IS. 29.25177.9W 0131202APR NEW ZEALAND NORTH CAPE 34.45173.3E 0138202APR EAST CAPE 37.55178.5E 0214202APR AUCKLAND(W) 37.15174.2E 0238202APR GISBORNE 38.75178.0E 0247202APR MILFORD SOUND 44.55167.8E 0249202APR NEW PLYMOUTH 39.15174.1E 0310202APR NAPIER 39.55176.9E 0316202APR WESTPORT 41.85171.2E 0332202APR AUCKLAND(E) 36.75175.0E 0332202APR WELLINGTON 41.55174.8E 0333202APR BLUFF 46.65168.3E 0351202APR NELSON 41.35173.3E 0426202APR LYTTELTON 43.65172.7E 0439202APR DUNEDIN 45.95170.5E 0506202APR

BULLETINS WILL BE ISSUED HOURLY OR SOONER IF CONDITIONS WARRANT. THE TSUNAMI WARNING AND WATCH WILL REMAIN IN EFFECT UNTIL FURTHER NOTICE.

TSUNAMI BULLETIN NUMBER 004 PACIFIC TSUNAMI WARNING CENTER /NOAA /NWS ISSUED AT 00132 02 APR 2007

THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.

NOTE: AREAS TO THE NORTH OF THE SOLOMONS SHOULD NOT BE SIGNIFICANTLY AFFECTED.

...A TSUNAMI WARNING AND WATCH REMAINS IN EFFECT...

A TSUNAMI WARNING IS IN EFFECT FOR

SOLOMON IS./ PAPUA NEW GUINEA / VANUATU / NEW CALEDONIA / AUSTRALIA / TUVALU / KIRIBATI / FIJI

A TSUNAMI WATCH IS IN EFFECT FOR

KERMADEC / NEW ZEALAND

FOR ALL OTHER PACIFIC AREAS, THIS MESSAGE IS AN ADVISORY ONLY.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME - 2040Z 01 APR 2007 COORDINATES - 8.6 SOUTH 157.2 EAST LOCATION - SOLOMON ISLANDS MAGNITUDE - 8.1

[SOPAC Miscellaneous Report 654 - Pearce] [53]

MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY

GAUGE LOCATION LAT LON TIME AMPL PER

HONIARA SB 9.4S 160.0E 22352 0.14M = 0.5FT 70MIN VANUATU VU 17.85 168.3E 23512 0.11M = 0.4FT 26MIN

LAT LATITUDE (N= NORTH, S= SOUTH) LON LONGITUDE (E =EAST, W =WEST) TIME TIME OF THE MEASUREMENT (Z = UTC = GREENWICH TIME) AMPL TSUNAMI AMPLITUDE MEASURED RELATIVE TO NORMAL SEA LEVEL. IT IS ...NOT... CREST -TO- TROUGH WAVE HEIGHT. IT IS ...NOT... CREST -TO- TROUGH WAVE HEIGHT. VALUES ARE GIVEN IN BOTH METERS(M) AND FEET(FT). PER PERIOD OF TIME IN MINUTES(MIN) FROM ONE WAVE TO THE NEXT.

EVALUATION

SEA LEVEL READINGS INDICATE A TSUNAMI WAS GENERATED. IT MAY HAVE BEEN DESTRUCTIVE ALONG COASTS NEAR THE EARTHQUAKE EPICENTER AND COULD ALSO BE A THREAT TO MORE DISTANT COASTS. AUTHORITIES SHOULD TAKE APPROPRIATE ACTION IN RESPONSE TO THIS POSSIBILITY. THIS CENTER WILL CONTINUE TO MONITOR SEA LEVEL DATA TO DETERMINE THE EXTENT AND SEVERITY OF THE THREAT.

FOR ALL AREAS - WHEN NO MAJOR WAVES ARE OBSERVED FOR TWO HOURS AFTER THE ESTIMATED TIME OF ARRIVAL OR DAMAGING WAVES HAVE NOT OCCURRED FOR AT LEAST TWO HOURS THEN LOCAL AUTHORITIES CAN ASSUME THE THREAT IS PASSED. DANGER TO BOATS AND COASTAL STRUCTURES CAN CONTINUE FOR SEVERAL HOURS DUE TO RAPID CURRENTS. AS LOCAL CONDITIONS CAN CAUSE A WIDE VARIATION IN TSUNAMI WAVE ACTION THE ALL CLEAR DETERMINATION MUST BE MADE BY LOCAL AUTHORITIES.

ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES. ACTUAL ARRIVAL TIMES MAY DIFFER AND THEINITIALWAVE MAY NOT BE THE LARGEST. THE TIME BETWEEN SUCCESSIVETSUNAMIWAVES CAN BE FIVE MINUTES TO ONE HOUR.

LOCATION COORDINATES ARRIVAL TIME

SOLOMON IS. MUNDA 8.4S157.2E 2039201 APR FALAMAE 7.4S155.6E 2103201 APR PANGGOE 6.9S157.2E 2120201 APR HONIARA 9.3S160.0E 2121201 APR GHATERE 7.8S159.2E 2122201 APR AUKI 8.8S160.6E 2134201 APR KIRAKIRA 10.45161.9E 2140201 APR PAPUA NEW GUINE AMUN 6.0S154.7E 2124201 APR KIETA 6.1S155.6E 2133201 APR

[SOPAC Miscellaneous Report 654 - Pearce] [54]

2007 Solomon Earthquake 3 DART52402 15° 1.2 0.008 0.8 0.004 0.4 0.900 ÿ ; 0.0 -0.904 -0.4 0.008 = -0k 1.2 120 240 360 480 600 0 120 240 360 480 600

0.008 3 DARi52403 0.4 0.004 02 0.000 0.2 -0.004 - 0- -0.008 = -10° 0.4 120 240 360 480 600 0 120 240 360 480 600

04Rabaul 0.4 0.2 0.2 0.0 0.0 -20° - 0.2 ![J!ryf -0.2 - 0.4 .0.4F-...... 120 240 360 480 600 -25° 0 120 240 300 480 602

1.2 oA-Noumera 0.8 0.2 - 0.4 -30" 0.0 140° 150° 160" 170° 180' 190 0.0 `n -0.4 "Mini -0.2 ¢ -0.8 -1.2 0.4 0 120 240 360 480 600 0.00 0.05 0.10 0.15 0.20 0 120 240 360 480 600 Time (min) Water height (m) Time [min}

Figure A2 -4: Tide gauge recordings for Solomon Islands tsunami 2 April, 2007

Figure A2 -5: Tide gauge recording for 2 April 2007 tsunami over the deep -water model scenario closest to the event.

[SOPAC Miscellaneous Report 654 - Pearce] [55]

(a) HONIARA, GUADALCANAL, SOLOMON ISLANDS-LAST 24 HOURS LAT 9 25.3' S LONG 159 57.3' E SIX MINUTE OBSERVATIONS & PREDICTIONS TO 20:54 02 APR 2007 UTC

1.2 PRE BS

1.0

0.8 G1 ö1 r E 0.6

0.4

0.2

20 21 2223 00 01 02 0304 0506070809 10 11 12 1314 15 16 17181920 21 01 April 2007 02 April 2007 (b)

HONIARA, GUADALCANAL, SOLOMON ISLANDS-LAST 24 HOURS LAT 9° 25.3' S LONG 159° 57.3' E SIX MINUTE RESIDUALS TO 20:54 02 APR 2007 UTC

0.5

0.4

0.3

0.2

_0 -2

-0.3

-0.4

-0.5

20 21 22 2300 01 0203 0405 06 07080910 11 12 13 14 1516 17 18 1920 21 01 April 2007 02 April 2007 Figure A2 -6: Tide gauge recording at Honiara for 2 April 2007 tsunami (a) Tide and tsunami signal (b) tsunami signal with predicted tide removed (ABoM)

[SOPAC Miscellaneous Report 654 - Pearce] [56]

(a) PORT VILA, EFATE, VANUATU - LAST 24 HOURS LAT 17' 45.7' S LONG 168' 17.6' E ONE MINUTE OBSERVATIONS & PREDICTIONS TO 20:01 02 APR 2007 UTC

1.6 FIRE BS 1.4

1.2

1.0 N

460.8 E 0.6

0.4

0.2

0.0

20 21 222300 01 0203040506 07 0809 10 11 121314151617181920 21 01 April 2007 02 April 2007 (b) PORT VILA, EFATE, VANUATU - LAST 24 HOURS LAT 17 45.7' S LONG 168 17.6' E ONE MINUTE RESIDUALS TO 20:01 02 APR 2007 UTC

0.5

0.4

0.3

0.2 {

0.1

-0.0 15 E -0.1

-0.2

-0.3

-0.4

-0.5

20 21 22 23 00 01 020304 050607080910 11 12 13 14 15 1617 181920 21 01 April 2007 02 April 2007

Figure A2 -7: Tide gauge recording at Port Vila for 2 April 2007 tsunami (a) tide and tsunami signal (b) tsunami signal with predicted tide removed (Source ABoM, 2007)

[SOPAC Miscellaneous Report 654 - Pearce] [57]

(ii) September 2007 Santa Cruz Tsunami Bulletins

The Santa Cruz earthquake 7.4Mw 2 September 2007, was within the range 6.5 -7.5Mw and the bulletin (rather than warning) produced by the PTWC advised of the potential for a Local (see A2 -4 (i)) Tsunami within 100km. The distances to Honiara and Port Villa were greater than 100km and travel estimated travel times greater than 1 hour. The Port Vila tide gauge recorded 4 cm amplitude (8cm peak -to- trough)..

TSUNAMI BULLETIN NUMBER 001 PACIFIC TSUNAMI WARNING CENTER/NOAA /NWS ISSUED AT 0121Z 02 SEP 2007

THIS BULLETIN APPLIES TO AREAS WITHIN AND BORDERING THE PACIFIC OCEAN AND ADJACENT SEAS...EXCEPT ALASKA...BRITISH COLUMBIA... WASHINGTON...OREGON AND CALIFORNIA.

...TSUNAMI INFORMATION BULLETIN...

THIS BULLETIN IS FOR INFORMATION ONLY.

THIS BULLETIN IS ISSUED AS ADVICE TO GOVERNMENT AGENCIES. ONLY NATIONAL AND LOCAL GOVERNMENT AGENCIES HAVE THE AUTHORITY TO MAKE DECISIONS REGARDING THE OFFICIAL STATE OF ALERT IN THEIR AREA AND ANY ACTIONS TO BE TAKEN IN RESPONSE.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME - 0105Z 02 SEP 2007 COORDINATES - 11.8 SOUTH 166.0 EAST DEPTH - SHALLOWER THAN 100 KM LOCATION- SANTA CRUZ ISLANDS MAGNITUDE - 7.4

EVALUATION

NO DESTRUCTIVE WIDESPREAD TSUNAMI THREAT EXISTS BASED ON HISTORICAL EARTHQUAKE AND TSUNAMI DATA.

HOWEVER - EARTHQUAKES OF THIS SIZE SOMETIMES GENERATE LOCAL TSUNAMI THAT CAN BE DESTRUCTIVE ALONG COASTS LOCATED WITHIN A HUNDRED KILOMETERS OF THE EARTHQUAKE EPICENTER. AUTHORITIES IN THE REGION OF THE EPICENTER SHOULD BE AWARE OF THIS POSSIBILITY AND TAKE APPROPRIATE ACTION.

THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT UNLESS ADDITIONAL INFORMATION BECOMES AVAILABLE.

THE WEST COAST /ALASKA TSUNAMI WARNING CENTER WILL ISSUE PRODUCTS FOR ALASKA...BRITISH COLUMBIA... WASHINGTON ...OREGON...CALIFORNIA. TSUNAMI BULLETIN NUMBER 002 PACIFIC TSUNAMI WARNING CENTER/NOAA /NWS ISSUED AT 0159Z 02 SEP 2007

THIS BULLETIN APPLIES TO AREAS WITHIN AND BORDERING THE PACIFIC OCEAN AND ADJACENT SEAS...EXCEPT ALASKA...BRITISH COLUMBIA... WASHINGTON...OREGON AND CALIFORNIA.

...TSUNAMI INFORMATION BULLETIN...

THIS BULLETIN IS FOR INFORMATION ONLY.

THIS BULLETIN IS ISSUED AS ADVICE TO GOVERNMENT AGENCIES. ONLY NATIONAL AND LOCAL GOVERNMENT AGENCIES HAVE THE AUTHORITY TO MAKE DECISIONS REGARDING THE OFFICIAL STATE OF ALERT IN THEIR AREA AND ANY ACTIONS TO BE TAKEN IN RESPONSE.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

[SOPAC Miscellaneous Report 654 - Pearce] [58]

ORIGIN TIME - 0105Z 02 SEP 2007 COORDINATES - 11.8 SOUTH 166.0 EAST DEPTH - SHALLOWER THAN 100 KM LOCATION- SANTA CRUZ ISLANDS MAGNITUDE - 7.3 (NOTE THIS IS REDUCED FROM 7.4)

EVALUATION

FURTHER SEISMIC ANALYSIS INDICATES THAT THIS EARTHQUAKE MAY BE THE KIND OF EARTHQUAKE THAT RUPTURES MORE SLOWLY AND HAS AN INCREASED POTENTIAL TO GENERATE TSUNAMI WAVES THAT COULD BE DAMAGING NEAR THE EPICENTER. THIS CENTER WILL CONTINUE TO MONITOR NEARBY SEA LEVEL GAUGES AND WILL REPORT ANY TSUNAMI WAVES THAT ARE OBSERVED.

THIS WILL BE THE FINAL BULLETIN ISSUED FOR THIS EVENT UNLESS ADDITIONAL INFORMATION BECOMES AVAILABLE.

THE WEST COAST /ALASKA TSUNAMI WARNING CENTER WILL ISSUE PRODUCTS FOR ALASKA...BRITISH COLUMBIA... WASHINGTON ...OREGON...CALIFORNIA. TSUNAMI BULLETIN NUMBER 003 PACIFIC TSUNAMI WARNING CENTER/NOAA /NWS ISSUED AT 0426Z 02 SEP 2007

THIS BULLETIN APPLIES TO AREAS WITHIN AND BORDERING THE PACIFIC OCEAN AND ADJACENT SEAS...EXCEPT ALASKA...BRITISH COLUMBIA... WASHINGTON...OREGON AND CALIFORNIA.

...TSUNAMI INFORMATION BULLETIN...

THIS BULLETIN IS FOR INFORMATION ONLY.

THIS BULLETIN IS ISSUED AS ADVICE TO GOVERNMENT AGENCIES. ONLY NATIONAL AND LOCAL GOVERNMENT AGENCIES HAVE THE AUTHORITY TO MAKE DECISIONS REGARDING THE OFFICIAL STATE OF ALERT IN THEIR AREA AND ANY ACTIONS TO BE TAKEN IN RESPONSE.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME - 0105Z 02 SEP 2007 COORDINATES - 11.8 SOUTH 166.0 EAST DEPTH -33 KM LOCATION- SANTA CRUZ ISLANDS MAGNITUDE - 7.3

MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY

GAUGE LOCATION LAT LON TIME AMPL PER

VANUATU VU 17.85 168.3E 0339Z 0.04M / 0.1FT 26MIN

LAT - LATITUDE (N- NORTH, S- SOUTH) LON - LONGITUDE (E -EAST, W -WEST) TIME - TIME OF THE MEASUREMENT (Z IS UTC IS GREENWICH TIME) AMPL - TSUNAMI AMPLITUDE MEASURED RELATIVE TO NORMAL SEA LEVEL. IT IS ...NOT... CREST -TO- TROUGH WAVE HEIGHT. VALUES ARE GIVEN IN BOTH METERS(M) AND FEET(FT). PER - PERIOD OF TIME IN MINUTES(MIN) FROM ONE WAVE TO THE NEXT.

EVALUATION

SEA LEVEL READINGS INDICATE A TSUNAMI WAS GENERATED. IT MAY HAVE BEEN DESTRUCTIVE ALONG COASTS NEAR THE EARTHQUAKE EPICENTER. FOR THOSE AREAS - WHEN NO MAJOR WAVES ARE OBSERVED FOR TWO HOURS AFTER THE ESTIMATED TIME OF ARRIVAL OR DAMAGING WAVES HAVE NOT OCCURRED FOR AT LEAST TWO HOURS THEN LOCAL AUTHORITIES CAN ASSUME THE THREAT IS PASSED. DANGER TO BOATS AND COASTAL STRUCTURES CAN CONTINUE FOR SEVERAL HOURS DUE TO THE CONTINUING SEA LEVEL CHANGES AND RAPID CURRENTS. AS LOCAL CONDITIONS CAN CAUSE A WIDE VARIATION IN TSUNAMI WAVE ACTION THE ALL CLEAR DETERMINATION MUST BE MADE BY LOCAL AUTHORITIES.

NO TSUNAMI THREAT EXISTS FOR OTHER COASTAL AREAS IN THE PACIFIC ALTHOUGH SOME OTHER AREAS MAY EXPERIENCE SMALL NON -DESTRUCTIVE SEA LEVEL CHANGES LASTING UP TO SEVERAL HOURS.

[SOPAC Miscellaneous Report 654 - Pearce] [59]

3 Tsunami Warning Related Background

(i) Summary of JMA /PTWC causal earthquake criteria

Table A2 -3: JMA and PTWC use simple criteria based on magnitude of the earthquake as a quick approximate assessment of an earthquakes potential to generate Local, Regional and Ocean -wide Tsunami ( Pearce, 2006).

Magnitude (Mw) PTWC&JMA Bulletin /Warning if less than 100km deep Mw and depth may change in first hour Amplitude for Destructive Tsunami>0 .5 m Potential for a Locally destructivetsunami 6.5 to 7.5 within 1 hr (100km)

Potential for a Regionally destructive tsunami within 3 hr (1000km) 7.6 to 7.8

Potential for an Ocean Wide destructive 7.9 and above tsunami

Table A2 -3 provides a summary of the simple criteria, based on magnitude, from PTWC /JMA and ATAS, used as a first approximation of an earthquake's potential to produce a local, regional or ocean -wide tsunami. Maximum tsunami wave height is more directly proportional to the vertical displacement of the rupture; however as magnitude can generally be determined within 10 -15 minutes, it is used in the waarning process to provide a quick approximation.The vertical displacement takes considerably longer and is more difficult to estistimate.

If an earthquake is deeper than 100km in the Earth's crust, no tsunami will be generated. An event in the range 6.5 to 7.5 Mw could produce a locally destructive tsunami affecting an area within 100 km or 1 hour's travel time. An event between 7.6 to 7.9 Mw could produce a regionally destructive tsunami affecting an area within 1000 km or 3 hrs travel time. Anything 7.9 Mw and above has the potential to produce an ocean -wide destructive tsunami. The PTWC & JMA also use the criteria, equal to or greater than 0.5 m amplitude as the definition of a destructive tsunami.

The PTWC Bulletins are issued as advice to government agencies. Only national and local government agencies have the authority to make decisions regarding the official state of alert in their area and any actions to be taken in response. All PTWC warnings and travel -times are in UTC (equivalent Z and GMT).

It is a national responsibility to provide public information; e.g. expected time of arrival in local & UTC time, recorded heights, the need to wait approx 2 -3 hours from expected or actual time of arrival for all clear.

[SOPAC Miscellaneous Report 654 - Pearce] [60]

(ii) Tsunami hazard sources The source of historical earthquake generated tsunami events around the Pacific is shown in Figure A2 -8 and Figure A2 -9 shows the time it would take a tsunami from any location to reach Honiara (i.e. inverse Tsunami Travel Time).

Figure A2 -8: Historical Tsunami Events in the Pacific and Eastern Indian Ocean. Circle size indicates earthquake magnitude and colour indicates tsunami intensity (SPSLCMP Pacific Country Report, June 2005).

Figure A2 -9: Inverse Tsunami Travel Times (hours) for Solomon Islands Capital, Honiara. (SPSLCMP Pacific Country Report, June 2006).

[SOPAC Miscellaneous Report 654 - Pearce] [61]

(iii) Real -Time Sea level data available for Tsunami monitoring

The Solomon Island sea level monitoring gauge at Honiara was installed in 1974 by University of Hawai'i. After the Banda Ache Tsunami in 2004, semi real -time data communications was installed by ABoM allowing access to 10 minute updates of 1 minute data.

Real -time sea level data for monitoring tsunami in the Pacific is available from other Pacific sea level monitoring gauges to all National Meteorological Agencies through the World Meteorological Organisations (WMO) global telecommunications system (GTS) network. Software is available from the IOC to decode and display this data. SOPAC is looking at a range of options for making this data and the analysis tools available to PICs.

Currently most Pacific island countries access even their own data through web services such as University of Hawai'i (Figure A2 -10) and Australian Bureau of Meteorology (ABoM) (Figure A2 -11 and Table A2 -4).

Most of these gauges are in lagoons or harbours and readings will include a range of additional affects such as shoaling and seiching as well as other background noise which can make it hard to distinguish a small tsunami signal. Tidal information to compliment that can complement Tsunami warning arrival times is available at: http: / /www.bom.gov.au /oceanography /tides /MAPS /pac.shtml.

NOAA Dart Buoy network data (Figure A2 -12) is available in semi real -time through http : / /www.ndbc.noaa.gov /dart.shtml these gauges are in deep water (about 3000 m) and are not affected by shoaling or seiching.

Unfortunately, it is not possible to locate the current type of DART buoy too close to a Trench, such as between the Solomon' s Trench and the Solomon Islands, due to the effects of the seismic signal overpowering the tsunami wave signal. Therefore there would be little chance of confirming a tsunami has been generated by an earthquake from the Solomons Trench before it reached parts of the Solomon Islands. However the gauges on the University of Hawai'i web page are useful for early warning for the northwest sources.

Figure A2 -10: Location of University of Hawai'i real -time sea level sites ( http: / /uhslc.soest .hawaii.edu /uhslc /data.html).

[SOPAC Miscellaneous Report 654 - Pearce] [62]

FSM Marshall Islands

Kiribati o'- Nauru

Solomon Islands Tuvalu -1o' - Samoa Fiji Vanuatu -2a'- Cook Islands Tonga

ao'-

1 3 0 ' ' 15 16 170' 20ä 210'

Figure A2 -11: Locations of Australia's seaframe tide gauge network for Southwest Pacific. This network is also used for tsunami monitoring (Warne 2007).

Table A2 -4: List of seaframe gauges in Pacific and update frequency available for monitoring tsunami. The update frequency of the Pacific array is in the process of being upgraded to 10min updates.

Port Numbers NOAA ARRAY Position (Access Update PDF Plots r I ATT [GLOSS L11-11 Station name Latitude Longitude [ethod Frequency 7 day 7 day 4428 03 115 [Colombo, Sn Lanka 116° 56 54" N 079' 51' 1Z E1`1-.S115 Minutes1 -min1 -min 480 r 12ISiboIga, Sumatera, SW Coast 0.1 °4a'N 098 °46'E GTS 115 Minutes 1-rnin !{Hirt

8815 119 I 008 !Yap. Caroline Island, FSM, Pacific Océan 09° 30' 30" N 138° DT 42" E 1 GTS115 Minutes1 -min1 -min

680 120 007rMalakal, Belau, Pacific Qcean D7°19' 48" N 1 134° 27' 48" E TS 15 Minutes1 -min1 -min

1 Port Handlers 1 PACIFIC ARRAY Position Accu Update.I PDF Plats

A.-FF-1- GLOSS UHLC I Stallan name Latitude 1 Longitude Method Frequency 1 day 7 day 13-1-1-410D 1Lombrum. Manus Island, Papua New Guinea 112° 02' 31.5" S 147° 22' 25.6' E [MSS RD Minutes1 -min 1 -min r56û7 Iâ6 1109 !Honiara, Guadalcanal, Solomon Islands 119° 25'44.1" 5.1159° 5T 19.3" E GMS Hourly &min ûmin 5732 r 115!Part Vila, Efate, Vanuatu 17°45' 19.2" S 168° IF27.T'E CMSS 10 Minutes 1{nin 1nin 6518 r 4 -03 !Jackson Bay, South Island, New Zealand 43° 58' 222" S 168° 36'5ß_p' E GMS Hourly 6-min 6 -min 5598 139 ß23 Avatiu, Rarotonga. Cook Islands F21°1217.1' S 159°4T 52' W GMS Hourly r -minrFrmin 6óe r 938 INuku álofa; Tongatapu, Tonga 21° D8' 12.5" S 175° 10'50.5" W CMSS10 minute1 -min1 -min 584 r 401 !Apia, Upolu, Samoa 13° 49' 36.4" S 171' 45'40.7' W CMSS 10 minute 7q5 722 018!cuva Viti Levu. Fiji 78°08'3.1 "S .178 °25'24.8 "E CM55 10 minute1 -min .1 -min 6707 r 4521Lautoka, Viti Levu, Fiji 17` 3û' 17.T' S 1177° 2617.7E[MSS 10 minute I1 -min1 -min

16744 I 121 1 025 IFongafale, Funafuti, Tuvalu 08 °30'8.9 "S 1179 °11'42.6 E.1CMSS10 minute 1 -min1 -min 879 113 eel(Betio, Tarawa, Kiribati 01° 21' 54,2" N1112° 55.58.8" E GMS Hóurly menin 5 -min 7ûA 114 054 1Aiwo, Nauru. Nauru 119 °31'45.9 "S1166 °54'36.2'E GMS Hourly 6 -min.6 -min 6758 112 ßD5 Uliga, Majuro. Marshall Islands 07° 06' 21.T' N 171°2Z22.1" E GP/IS Hourly T -min 6 -min

75 115 0111 IDekehtik, Pohnpei, FSM e6° 58' 49.9" N 1 158° 1Z 0.8" E CMSS 1f minute 1 -nun1 -min

1

[SOPAC Miscellaneous Report 654 - Pearce] [63]

DART LOCATIONS March 2007

105.0E 1350E 1135 OE 135 OW

,..tiAfJT .' * . Clik,n DART * yk Planned Cliileon pJaonnYCldle,yn eJt fi PóiunedChikan 45 GS P -P acilic

Completed 1 281 * Palled 1111 *

Tolal R elvrco k1391

Figure A2 -12: Locations of Deep ocean tsunami monitoring buoy network.

[SOPAC Miscellaneous Report 654 - Pearce] [64]

APPENDIX 3

Additional Modelling

1 Modelling of major tsunami for sources around the Pacific

The deep -water modelling for the 39 magnitude 9 tsunami sources around the Pacific, used in the composite in Section 4, are shown in Figure A3 -1. Note that the main energy is beamed perpendicular to the trench and then channelled by bathymetry. The Solomons Trench source Figures A3 -1 (31, 32, 33 & 34) are the most critical for Solomon Islands..

120' 140' 160' 180' 200' 220' 240' 280'280' 300' 60' 60'

40' 40

20 20

o

-20' -20'

-40 -40'

-60' 60' 12.0' 140 160 16o. 200' 220 240' 260' 280' 300' m 1 00 0.1 0-2 0.3 0.4 0 -5 2 0.0 0.1 0.2 0.3 04 0.5 120 140 160' 180 200 220' 240' 260 2817' 300 120 1,0 1613- 160- 200' 220' 240' 26o. 280

60 - - i iLi 60

0/4 r

-60I - - - . -CO' 0 -0 0-1 0.2 0.3 0 -4 0.5 4 120' 140' 180' 160' 200' 220 240' 200' 280' 300' 120' 140 160 180- 200' 220' 240' 260' 280- 60' 60- 60'

40' 40

20' 20-

o-

-20'

-40'

-e0' : -60' 160' 160 200' 220' 240' 260' 280' 300' 1217' 140 160' i80 200' 220- 240' 260' 280'300' m 00 0.1 0.2 0.3 0.4 0.5 5 0.0 0.1 0.2 013 OA 0.5 6

[SOPAC Miscellaneous Report 654 - Pearce] [65]

120' 140 180 180. 200 220' 240' 260_260' 300' 120' 140 160' 180" 200' 220' 240' 260' 280' 300 80' - 60 60'

40' 40' 40'

20' 20

0' a

-40'

so. _60. 120' 140 169 180200 220' 240' 259' 280'300' 120' 140' 180' 160 200' 220' 240' 280 280' 300' m Fri 0.0 0.1 0.2 0.3 0.4 0.5 7 8 0.0 0.1 0.2 013 0.4 0.5 220' 240' 260 260' 300 120' 146' 160' 180 200' 226Y 240 260280300 fio ¡ - . i A 60'

40 49'

20' 20'

0 0

-40

. -60. 120' 140 150180 200'220' 240 260280 300' m 9 10 0.0 0.1 0.2 0.3 0.4 0.5

180' 260' 220' 240' 260' 290' 300'

120' 140" 160' 180' 200 220" 240' 260' 280' 300' Im 9.0 0"1 02 0.3 0:4 0"5 11 0.1 0.2 0.3 0.4 05

120. 140- 160- 180 200 220. 240'260 280' 300' 120' 140 160' 160 200 220' 240 260' 280 300 60 60 90'

4 40' 40'

20' 20'

0

-20'

-4 -40

-60 . 120' 140 160' 160' 200' 220' 249' 260 20.7 360 120' 140' 160' 180' 200' 220'240 280. 280' 300' 'Mr m 0.0 01 02 0.3 03 05 I m 14 0.0 0.1 02 0.3 0A 0.5 13

[SOPAC Miscellaneous Report 654 - Pearce] [66]

s20 140' 160 180 200' 220' 240' 26o' 280' 3ao 120. 14o. 1 s 1943 200' 220' 240' 2s0.2s0 390 ". p fio - so so s0 r

w ! ! w rr- 4e ao - ap'

.. 2a 20 - I t,, .} 7 e 0' . [

-20 ' . -20'

-40' - -ae' 40' y t 40

4 -60 -60. -60' 120' 140' 160 180' 200 220 290' 26o280300' 120 140' 160' t80' 200' 220 240 260" 280' 300' 1 m m 16 0"0 0.1 0.2 0.3 0.9 0.5 0.0 0.1 02 0.3 0.4 0"5 15 120 190 160' 180 200' 220' 240'260' 280' 300' 120' 140' 160 180' 200' 220' 240' 260' 280' 300 _ 60 60 60' +1.;J 60' .

. A ! rT_ r r 9° 40' 40

1 ' 20 2 0' aa 20 -. J

. S . . 0 0" 8 ..,t -20' 20 -20

-aO' _á°' r I -r.,.. .

r 1

so -60' 120 140' 160' 1N 200' 220' 240' 260280 300 120' 140 160 160' 200 220 240' 260' 260' 300' - - - -1m I,- I m 18 0.0 0.1 0.2 0:3 0.4 0.5 17 0.0 0"i 02 0.3 0.4 0"S 120' 140 160 480 200' 220' 240'260' 280' 300' i 1.". . 60 120 140' 160' t60' 200 220' 240' 260' 260' 300. 60 80' w r*- l a° - a r'. " 20 20 20 -!>,y fl 0 !ai- ._ o 77'tt'' ., i -20 . . . + -20 . -20.

r . 4o

.E 120' 140 160' 180' 200 220 240'260 280' 300 -BO' m 120' 140'160' 186' 200' 220' 240' 260' 280'300' 19 00 0.1 02 0.3 0.4 0.5 m 20 00 0.1 03 0.3 0.4 0.5 120 140' 160' 180' 200"220' 240' 260' 260' 300' 120 140" 160' 160 200' 220 240260' 280' 300' . _" ...... 60 " 60' 60 i 60 4.... r . .. , rr_ i}r 40- 40 4p'

20 20

. N. Z p

',` 0' ` 20' -20 . -20' i 1-40 _40' 4 0 -40' y 1}

-60' -60' -60' 120 140' 16o' 160'200' 220' 240' 260' 280 300' 120' 140' 160' 180' 200'22o' 240' 260' 260300' m m 22 0.0 0.1 0.2 0"3 0.4 0"5 21 on 0.1 0.2 03 0.4 0.5

[SOPAC Miscellaneous Report 654 - Pearce] [67]

120' 140' 160 180' 200' 220' 240' 260' 280 300' 123' 140' 180 180 230' 220' 240' 260' 280' 300'

83 /^ - 80 60 1 r -lffi 60'

A 40 40

20 20 20 20

0 0

-20 -20

40' -40"

_6o -so. 120' 140' 160 180' 200'220' 240 260 280 300' 120' 140' 160' 100' 200' 220'240' 260' 280' 330' m m 23 0.0 0.1 02 0 :3 0.4 0.5 24 3.3 0.1 0.2 0.$ 0,4 0.5 nnn nano non. 120' 140' 160" 180 200' 220' 240 260 200 300' 120' m wn xnn so' t 60' 60' 60

40" 4D' 40' 40

20' 20 20' 20'

0 0 0

- 20' -20' -20'

-40' J0' -40 -40'

-60' 120' 140 160' 180 200 220 240 260 260' 300' -60. Im 120' 140' 160 180' 200' 220' 240' 260280 300' 25 0.0 0.1 0,2 0.3 0.4 0.5 26 0:0 0.1 0.2 0.3 0.4 0.5 140 160' 160 204 220 240 260 260 160' 180' 200' 220' 240' 200' 280' 300'

27 0.0 0.1 0.2 0.3 0 "4 0 "5 28 0"0 0.1 02 0.3 0w 0.5

120 140' 160' 60

29 0.1 02 0.3 D.4 0.5

[SOPAC Miscellaneous Report 654 - Pearce] [68]

120' 140' 160' 180 200 220' 240' 260' 280' 300' rji 20 140' 160 180' 200' 220' 240' 200' 280' 300 60' ' 60' 60' 60

40 40

2 20

0'

-2 - 20'

40 -40' -40'

-60' - 60' 120' 260'280' 300' 120' 140' 160 180' 200' 220' 240' 260' 280' 300' m 31 0.0 0.1 0.2 0.3 0.4 0.5 32 0.0 0.1 0.2 Si 0 "4 0.6 120" 140 160 180 200 220" 240 260' 280 300' 120' 140' 160' 160 200' 220 240 269 280 30 T 60" 60 60 60

4 40 40 40'

20 20

-2 -20'

40 4

-60' 120' 140' 160' 180' 200' 220' 240 260 280'300' 1m 33 0.0 0.1 0.2 0.3 0.4 0.5 120' 140 160 180" 200 220' 240'260 280' 300' 120 140 160 15.0' 200' 220 40 200 260 300'

60" " 60' 60' 60" A 40' 40' 4 40'

2 20' 20' 20'

0' 0

-20 -2 -20

-40' -40' -40'

60' -60 80' - - 60' 120' 140' 160' 180 200' 220240 260' 260 300' 120' 140 160' 180' 200 220' 240'260' 280' 300' !m 36 0.0 0.1 02 0.3 0.4 0"5 35 9.0 0 1 3.2 G.3 0.4 0.5 120 140" 160' 160' 200 220 120 140 103 130 23.7 220 Zar 260' 280 300' 00 r 60'

d0 40'

20' 20'

0"

_20

-40' -40'

_.-154Y 120' 140' 160 180 200' 220. 240'260' 200' 300' im 38 37 0.0 0.1 0.2 0.3 0.4 0.5

[SOPAC Miscellaneous Report 654 - Pearce] [69]

120' 140 160 180' 200 220 240' 260' 280 300"

BO' 80'

40' 40'

20' 20

0

-20 -20'

-40' -40'

-80' 120' 140' 160' 180 200' 220'240' 260. 280' 300' m 39 0.0 0.7 02 0.2. 0.4 0.5

Figure A3 -1: Sources for 9Mw generated tsunami around the Pacific ( Thomas, personal comm. 2007)

[SOPAC Miscellaneous Report 654 - Pearce] [70]

2 MOSTscenarios for sources affecting Solomon Islands

(i) Solomons Trench

MOST ( Method of Splitting Tsunami) Model scenarios for 9.0, 8.5 ,8.0 and 7.5 Mw potential events on the Solomons Trench are at Figure A3 -3. For events up to 8 Mw most of the energy is contained within the Solomon Islands or focused to SW. Above this magnitude, by virtue of the larger rupture area (Figure A3 -2), the energy is also focused toNE.

156` 158' 160°

Historical Earthquakes C72007 Rupture Area ^ -6 Potential Triggered Earthquakes Mag 9 Earthquake Volcanoes

8°

IKavrle&l',mermen' .

-10

100 km I939111

Figure A3 -2: Pink represents area ruptured during 2 April event. Grey the area that would need to rupture to produce a Magnitude 9 generated tsunami event. (Cummins 2007)

,...... ,.... . ,. ,.. GI... ta t..1's :. ,:t 11.11..... - .1...." ` G _ : r a .. .. ~ .O^ . . . ''j p-+- .p Ç A I `E 4 f . .

, ..r.,.....-- ....,. .ti.., ...... ,,.....- ......

. `. . - y... ,....- -- ..,. ... ,,,-^,- 4. Ir. ÿ

1- -- .. q+dy ¡p' ` ° q£ s 1 `F S. r . .. .'

r1 4 }

v 1-,4-- A . . - Figure A3 -3: Solomon Islands Trench most significant, with very short warning times (ABoM 2007)

[SOPAC Miscellaneous Report 654 - Pearce] [71]

(ii) New Hebrides Trench

The New Hebrides Trench to the south east of Solomon Islands has travel times of less than 2 hours. Figure A3 -4 shows the 8.5 Mw, 8.0 Mw and 7.5 Mw model scenarios for the New Hebrides Trench.

.....n,. . ., >E .,..., .... 3.363, .,.Ifc.e1HUM .,,... -- ..., #Ww . ,.,..., '4 7V y.131^ . .felsa.

t\ii _,S.: ,.,.

p -_ .. a.`f `E% o - ÿ S jR Ç . .. '- . r..r,g. 1.. ei' 1

.. Il . 1 r7rc .e r s n.r .1 n ',d, °

PAM a 17 Pa 11215113 141.931E Yy...s xc ..p. 1M i M .16 - - wy.i y,l.

}+..... - ` +... ° 4 iii [l"4i. J ,i rA' . .

i

Figure A3 -4: New Hebrides trench a critical source from SE with limited warning time (ABoM 2007)

[SOPAC Miscellaneous Report 654 - Pearce] [72]

(iii) Mariana Trench

Tsunami events from the Mariana Trench to the NW would have longer travel times (4 -6 hours) to the Solomon Islands. Figure A3 -5 shows the 9 Mw and 8.5 Mw model scenarios.

A 1! I fl TS lB 1S ]A lG Y SI il F. NO 15i Na

Figure A3 -5: Mariana Trench a critical source from NW with approximately 4 hours lead time (ABoM 2007)

[SOPAC Miscellaneous Report 654 - Pearce]