DOCSLIB.ORG

Video Monitoring Reveals Pulsating Vents and Propagation Path of Fissure Eruption During the March 2011 Pu'u

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Video Monitoring Reveals Pulsating Vents and Propagation Path of Fissure Eruption During the March 2011 Pu'u Journal of Volcanology and Geothermal Research 330 (2017) 43–55 Contents lists available at ScienceDirect Journal of Volcanology and Geothermal Research journal homepage: www.elsevier.com/locate/jvolgeores Video monitoring reveals pulsating vents and propagation path of fissure eruption during the March 2011 Pu'u 'Ō'ō eruption, Kilauea volcano Tanja Witt ⁎,ThomasR.Walter GFZ German Research Centre for Geosciences, Section 2.1: Physics of Earthquakes and Volcanoes, Telegrafenberg, 14473 Potsdam, Germany article info abstract Article history: Lava fountains are a common eruptive feature of basaltic volcanoes. Many lava fountains result from fissure erup- Received 12 April 2016 tions and are associated with the alignment of active vents and rising gas bubbles in the conduit. Visual reports Received in revised form 18 November 2016 suggest that lava fountain pulses may occur in chorus at adjacent vents. The mechanisms behind such a chorus of Accepted 18 November 2016 lava fountains and the underlying processes are, however, not fully understood. Available online 5 December 2016 The March 2011 eruption at Pu'u 'Ō'ō (Kilauea volcano) was an exceptional fissure eruption that was well mon- fi fi Keywords: itored and could be closely approached by eld geologists. The ssure eruption occurred along groups of individ- Kilauea volcano ual vents aligned above the feeding dyke. We investigate video data acquired during the early stages of the Fissure eruption eruption to measure the height, width and velocity of the ejecta leaving eight vents. Using a Sobel edge-detection Vent migration algorithm, the activity level of the lava fountains at the vents was determined, revealing a similarity in the erup- Bubbling magma tion height and frequency. Based on this lava fountain time series, we estimate the direction and degree of cor- Video monitoring relation between the different vents. We find that the height and velocity of the eruptions display a small but systematic shift in time along the vents, indicating a lateral migration of lava fountaining at a rate of ~11 m/s from W to E. This finding is in agreement with a propagation model of a pressure wave originating at the Kilauea volcano and propagating through the dyke at ~10 m/s from W to E. Based on this approach from videos only 30 s long, we are able to obtain indirect constraints on the physical dyke parameters, with important implications for lateral magma flow processes at depth. This work shows that the recording and analysis of video data provide important constraints on the mechanisms of lava fountain pulses. Even though the video sequence is short, it al- lows for the confirmation of the magma propagation direction and a first-order estimation of the dyke dimensions. © 2016 Elsevier B.V. All rights reserved. 1. Introduction member mechanisms of these lateral and eccentric fissures are (i) hor- izontal dyke propagation or (ii) divergence of a magma path at great Fissure eruptions have been observed at Hekla (1947, 1970), Askja depth followed by predominantly vertical dyke ascent. Distinguishing (1961), Mauna Loa (1984), Kilauea (1983–2015, continuing), Dabbahu between these two mechanisms is often difficult (Acocella and Neri, (2005), Reunion (2006), Tolbachik (2013), and many other volcanoes 2003), which is why observation of a lateral-flow mechanism is so im- in past decades (Global Volcanism Project, 2016; Siebert et al., 2011). portant to understanding the link between fissure eruptions and their Commonly referred to as “Hawaiian-type eruptions”, they are predom- source region. inant on ocean islands and at divergent plate margins but also occur at Here, we demonstrate the utility of video monitoring in the study convergent margins and in intraplate settings (Valentine and Gregg, of fissure eruptions. We consider an exceptionally well-monitored 2008). Fissure eruptions can occur kilometers away from the volcano case example of a fissure eruption that occurred at Kilauea, Hawaii summit to which they are connected via crustal flow paths rather than (Poland, 2014). In March 2011, a fissureeruptionoccurredinthe forming a continuous fissure at the surface. At Mauna Loa (Hawaii), fis- East Rift Zone of Kilauea and was located at a distance of over sure eruptions have opened at distances exceeding 15 km from the vol- 17 km from the Kilauea summit crater (Orr et al., 2013a). Specifically, cano summit (Lockwood et al., 1985). The location of a fissure interacts the eruption occurred along several aligned vents, which followed the with the crustal stress field (Walter and Amelung, 2006). At Etna volca- surface expression of a geodetically and seismically inferred dyke intru- no (Italy), fissure eruptions may occur close to inhabited areas on the sion (Lundgren et al., 2013). A lateral magma flow is geometrically hy- lower slope of the volcanic edifice (Acocella and Neri, 2009). The end- pothesized because the eruption vents formed at a significant lateral distance from Kilauea (Lundgren et al., 2013). Additionally, fluctuations ⁎ Corresponding author. in the lava lake level at Kilauea were coincident with activity changes at E-mail address: [email protected] (T. Witt). Pu'u 'Ō'ō (Poland, 2014), suggesting a hydraulic connection (Montagna http://dx.doi.org/10.1016/j.jvolgeores.2016.11.012 0377-0273/© 2016 Elsevier B.V. All rights reserved. 44 T. Witt, T.R. Walter / Journal of Volcanology and Geothermal Research 330 (2017) 43–55 and Gonnermann, 2013). However, to date, no direct observations have of magmatic gas, magma and pyroclastic products. The height of a foun- tested or quantified the lateral magma flow concept based on vent ac- tain can reach hundreds of meters. The dynamics of lava fountains may tivity at an erupting fissure. Because fissures open sequentially and be governed by gas bubble layers that either form during magma rise or show venting activity that appears to be correlated to those fissures previously accumulate at depth and drive the intensity of the eruption (Björnsson, 1985; Jackson et al., 1975; Mangan et al., 1995), lateral (Allard et al., 2005; Manga, 1996). So far, this description has considered magma propagation may continue to dominate the subterranean only the vertical dynamics, but fissure eruptions represent structures system. with a considerable horizontal extent. Therefore, we attempt here to in- The pulsating behaviour of vents can be investigated in detail via vestigate the horizontal dynamics as well. video analysis, as this study shows. Video analyses have been per- formed elsewhere to investigate volcanic processes because camera 2.1. Hawaiian lava fountains and venting activity monitoring facilitates continuous footage at reasonable costs and in high resolution (Diefenbach et al., 2011; Walter, 2011). This moni- The classic type of lava fountaining can be regularly observed on Ha- toring technique is flexible over a wide range of time scales and al- waii and is therefore often referred to as “Hawaiian type”.Highlyener- lows both a broad spatial coverage and a precise measurement of getic fountain pulses can reach heights of up to 1500 m (Allard et al., local surface processes (e.g., Bluth and Rose, 2004; Honda and 2005). Lava fountains are thought to be caused by the rise of a mixture Nagai, 2002). However, for many applications, it has a lower preci- of gas bubbles and low-viscosity magma to the surface (Parfitt, 2004). sion than ground-based surveying techniques (Diefenbach et al., The gas bubbles may be formed at different depths due to volumetric 2011). The methods used for video monitoring are separated into expansion of volatiles and may be trapped in storage regions prior to satellite-, aerial- and terrestrial-based methods (Walter et al., eruption. 2013), in which quantitative image analysis, digital flow-field com- Different conceptual models of lava fountain dynamics suggest putation, image sequence matching and other photogrammetric different gas compositions (proportion of CO2 or H2O), formation and computer vision algorithms are applied (e.g., Baldi et al., 2000; mechanisms and bubble accumulation zones (Parfitt, 2004). The James et al., 2007; James et al., 2006; Julio Miranda and Delgado collapsing foam model (CF, e.g., Jaupart and Vergniolle, 1988; Granados, 2003). Common applications in volcanology have includ- Jaupart and Vergniolle, 1989; Vergniolle and Jaupart, 1986; ed the study of deforming craters (Patrick et al., 2010), extrusion Vergniolle and Jaupart, 1990; Vergniolle and Mangan, 2000)as- (Major et al., 2009) and collapse of lava domes (Walter, 2011), sumes that CO2 is the driving gas. Between the conduit and the changes in the volcanic topography (Cecchi et al., 2003), deforma- magma storage zone, bubbles form and become trapped. The bub- tion patterns, displacement vectors (Major et al., 2009) and other bles accumulate as a foam (Parfitt, 2004)oralayerofgas(Allard physical parameters, such as ejection velocities of pyroclasts et al., 2005)atasignificant depth, as much as 1.5 km beneath the (Taddeucci et al., 2012a; Taddeucci et al., 2012b). Using thermal surface. Some bubbles collapse, coalesce or ascend as an annular cameras a lava flow flux variations (James et al., 2007), cyclic rising two-phase flow of gas and melt through the conduit, with the two and falling of a lava lake surface during unrest (Spampinato et al., phases exhibiting significantly different flow velocities. The erup- 2013), dome building (Schneider et al., 2008), fumarole activity tion style depends on whether the foam is collapsing instanta- (Stevenson and Varley, 2008) and many other volcanic
Load more

Recommended publications
  • Volcanic Landforms: the Landform Which Is Formed from the Material Thrown out to the Surface During Volcanic Activity Is Called Extrusive Landform
    Download Testbook App Volcanic Geography NCERT Notes Landforms For UPSC ABOUT VOLCANIC LANDFORM: Volcanic landform is categorised into two types they are:extrusive and intrusive landforms. This division is done based on whether magma cools within the crust or above the crust. By the cooling process of magma different types of rock are formed. Like: Plutonic rock, it is a rock which is magma within the crust whereas Igneous rock is formed by the cooling of lava above the surface. Along with that “igneous rock” term is also used to refer to all rocks of volcanic origin. Extrusive Volcanic Landforms: The landform which is formed from the material thrown out to the surface during volcanic activity is called extrusive landform. The materials which are thrown out during volcanic activity are: lava flows, pyroclastic debris, volcanic bombs, ash, dust and gases such as nitrogen compounds, sulphur compounds and minor amounts of chlorine, hydrogen and argon. Conical Vent and Fissure Vent: Conical Vent: It is a narrow cylindrical vent through which magma flows out violently. Such vents are commonly seen in andesitic volcanism. Fissure vent: Such vent is a narrow, linear through which lava erupts with any kind of explosive events. Such vents are usually seen in basaltic volcanism. Mid-Ocean Ridges: The volcanoes which are found in oceanic areas are called mid-ocean ridges. In them there is a system of mid-ocean ridges stretching for over 70000 km all through the ocean basins. And the central part of such a ridge usually gets frequent eruptions. Composite Type Volcanic Landforms: Such volcanic landforms are also called stratovolcanoes.
    [Show full text]
  • Magma Emplacement and Deformation in Rhyolitic Dykes: Insight Into Magmatic Outgassing
    MAGMA EMPLACEMENT AND DEFORMATION IN RHYOLITIC DYKES: INSIGHT INTO MAGMATIC OUTGASSING Presented for the degree of Ph.D. by Ellen Marie McGowan MGeol (The University of Leicester, 2011) Initial submission January 2016 Final submission September 2016 Lancaster Environment Centre, Lancaster University Declaration I, Ellen Marie McGowan, hereby declare that the content of this thesis is the result of my own work, and that no part of the work has been submitted in substantially the same form for the award of a higher degree elsewhere. This thesis is dedicated to Nan-Nar, who sadly passed away in 2015. Nan, you taught our family the importance and meaning of love, we love you. Abstract Exposed rhyolitic dykes at eroded volcanoes arguably provide in situ records of conduit processes during rhyolitic eruptions, thus bridging the gap between surface and sub-surface processes. This study involved micro- to macro-scale analysis of the textures and water content within shallow (emplacement depths <500 m) rhyolitic dykes at two Icelandic central volcanoes. It is demonstrated that dyke propagation commenced with the intrusion of gas- charged currents that were laden with particles, and that the distribution of intruded particles and degree of magmatic overpressure required for dyke propagation were governed by the country rock permeability and strength, with pre-existing fractures playing a pivotal governing role. During this stage of dyke evolution significant amounts of exsolved gas may have escaped. Furthermore, during later magma emplacement within the dyke interiors, particles that were intruded and deposited during the initial phase were sometimes preserved at the dyke margins, forming dyke- marginal external tuffisite veins, which would have been capable of facilitating persistent outgassing during dyke growth.
    [Show full text]
  • LERZ) Eruption of Kīlauea Volcano: Fissure 8 Prognosis and Ongoing Hazards
    COOPERATOR REPORT TO HAWAII COUNTY CIVIL DEFENSE Preliminary Analysis of the ongoing Lower East Rift Zone (LERZ) eruption of Kīlauea Volcano: Fissure 8 Prognosis and Ongoing Hazards Prepared by the U.S. Geological Survey Hawaiian Volcano Observatory July 15, 2018 (V 1.1) Introduction In late April 2018, the long-lived Puʻu ʻŌʻō vent collapsed, setting off a chain of events that would result in a vigorous eruption in the lower East Rift Zone of Kīlauea Volcano, as well as the draining of the summit lava lake and magmatic system and the subsequent collapse of much of the floor of the Kīlauea caldera. Both events originated in Lava Flow Hazard Zone (LFHZ) 1 (Wright et al, 1992), which encompasses the part of the volcano that is most frequently affected by volcanic activity. We examine here the possible and potential impacts of the ongoing eruptive activity in the lower East Rift Zone (LERZ) of Kīlauea Volcano, and specifically that from fissure 8 (fig. 1). Fissure 8 has been the dominant lava producer during the 2018 LERZ eruption, which began on May 3, 2018, in Leilani Estates, following intrusion of magma from the middle and upper East Rift Zone, as well as the volcano’s summit, into the LERZ. The onset of downrift intrusion was accompanied by collapse of the Puʻu ʻŌʻō vent, which started on April 30 and lasted several days. Kīlauea Volcano's shallow summit magma reservoir began deflating on about May 2, illustrating the magmatic connection between the LERZ and the summit. Early LERZ fissures erupted cooler lava that had likely been stored within the East Rift Zone, but was pushed out in front of hotter magma arriving from farther uprift.
    [Show full text]
  • Lunar Crater Volcanic Field (Reveille and Pancake Ranges, Basin and Range Province, Nevada, USA)
    Research Paper GEOSPHERE Lunar Crater volcanic field (Reveille and Pancake Ranges, Basin and Range Province, Nevada, USA) 1 2,3 4 5 4 5 1 GEOSPHERE; v. 13, no. 2 Greg A. Valentine , Joaquín A. Cortés , Elisabeth Widom , Eugene I. Smith , Christine Rasoazanamparany , Racheal Johnsen , Jason P. Briner , Andrew G. Harp1, and Brent Turrin6 doi:10.1130/GES01428.1 1Department of Geology, 126 Cooke Hall, University at Buffalo, Buffalo, New York 14260, USA 2School of Geosciences, The Grant Institute, The Kings Buildings, James Hutton Road, University of Edinburgh, Edinburgh, EH 3FE, UK 3School of Civil Engineering and Geosciences, Newcastle University, Newcastle, NE1 7RU, UK 31 figures; 3 tables; 3 supplemental files 4Department of Geology and Environmental Earth Science, Shideler Hall, Miami University, Oxford, Ohio 45056, USA 5Department of Geoscience, 4505 S. Maryland Parkway, University of Nevada Las Vegas, Las Vegas, Nevada 89154, USA CORRESPONDENCE: gav4@ buffalo .edu 6Department of Earth and Planetary Sciences, 610 Taylor Road, Rutgers University, Piscataway, New Jersey 08854-8066, USA CITATION: Valentine, G.A., Cortés, J.A., Widom, ABSTRACT some of the erupted magmas. The LCVF exhibits clustering in the form of E., Smith, E.I., Rasoazanamparany, C., Johnsen, R., Briner, J.P., Harp, A.G., and Turrin, B., 2017, overlapping and colocated monogenetic volcanoes that were separated by Lunar Crater volcanic field (Reveille and Pancake The Lunar Crater volcanic field (LCVF) in central Nevada (USA) is domi­ variable amounts of time to as much as several hundred thousand years, but Ranges, Basin and Range Province, Nevada, USA): nated by monogenetic mafic volcanoes spanning the late Miocene to Pleisto­ without sustained crustal reservoirs between the episodes.
    [Show full text]
  • Assessing Eruption Column Height in Ancient Flood Basalt Eruptions
    This is a repository copy of Assessing eruption column height in ancient flood basalt eruptions. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/109782/ Version: Accepted Version Article: Glaze, LS, Self, S, Schmidt, A orcid.org/0000-0001-8759-2843 et al. (1 more author) (2017) Assessing eruption column height in ancient flood basalt eruptions. Earth and Planetary Science Letters, 457. pp. 263-270. ISSN 0012-821X https://doi.org/10.1016/j.epsl.2014.07.043 © 2016 Elsevier B.V. and United States Government as represented by the Administrator of the National Aeronautics and Space Administration. Published by Elsevier B.V. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version - refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher’s website. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request.
    [Show full text]
  • Controls on Lunar Basaltic Volcanic Eruption Structure and Morphology: 2 Gas Release Patterns in Sequential Eruption Phases 3 L
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Lancaster E-Prints 1 Controls on Lunar Basaltic Volcanic Eruption Structure and Morphology: 2 Gas Release Patterns in Sequential Eruption Phases 3 L. Wilson1,2 and J. W. Head2 4 1Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK 5 2Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 6 02912 USA 7 8 Key Points: 9 Relationships between a diverse array of lunar mare effusive and explosive volcanic 10 deposits and landforms have previously been poorly understood. 11 Four stages in the generation, ascent and eruption of magma and gas release patterns are 12 identified and characterized. 13 Specific effusive, explosive volcanic deposits and landforms are linked to these four 14 stages in lunar mare basalt eruptions in a predictive and integrated manner. 15 16 Abstract 17 Assessment of mare basalt gas release patterns during individual eruptions provides the basis for 18 predicting the effect of vesiculation processes on the structure and morphology of associated 19 features. We subdivide typical lunar eruptions into four phases: Phase 1, dike penetrates to the 20 surface, transient gas release phase; Phase 2, dike base still rising, high flux hawaiian eruptive 21 phase; Phase 3, dike equilibration, lower flux hawaiian to strombolian transition phase; Phase 4, 22 dike closing, strombolian vesicular flow phase. We show how these four phases of mare basalt 23 volatile release, together with total dike volumes, initial magma volatile content, vent 24 configuration and magma discharge rate, can help relate the wide range of apparently disparate 25 lunar volcanic features (pyroclastic mantles, small shield volcanoes, compound flow fields, 26 sinuous rilles, long lava flows, pyroclastic cones, summit pit craters, irregular mare patches 27 (IMPs) and ring moat dome structures (RMDSs)) to a common set of eruption processes.
    [Show full text]
  • Episodic Triggering of the Rise of Resident Small-Scale Basaltic Magmas from the Mantle
    IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan Forecasting Volcanic Activity - Reading and translating the messages of nature for society 1A1_3B-O1 Room A5 Date/Time: July 21 8:45-9:00 Episodic triggering of the rise of resident small-scale basaltic magmas from the mantle Ian E M Smith1, Lucy E McGee1, Shane J Cronin2, Jan M Lindsay1 1Geology-School of Environment, University of Auckland, New Zealand, 2Institute of Natural Resources, Massey University, New Zealand E-mail: [email protected] Small scale basaltic magmatic systems are expressed at the Earth’s surface as fields of individual volcanoes, each representing a discrete batch of magma erupted within a defined period of time (weeks to years). Characteristically each volcano shows chemical compositions that are distinct from that of other volcanoes in the field and this can be explained in terms of variation in the parameters of magma generation, specifically depth and proportion of melting. Fundamental to an understanding of the behaviour of such systems is the behaviour of their mantle source. The scale of these systems precludes large scale plume related processes such as those implicated in the origin of large igneous provinces. Rather, adiabatic melting linked to small scale mantle convection can explain both the size and longevity (up to 10 Ma) of these systems. However, the important questions are does each volcano in a field represent a single melting event and what triggers each event? To address these questions we investigate the Quaternary Auckland Volcanic Field (AVF) in northern New Zealand. The field exhibits the common volcanological and chemical behaviour of classic monogenetic volcanic systems.
    [Show full text]
  • Oregon Geology
    OREGOM GEOLOGY published by the Oregon Department of Geology and Mineral Industries VOLUME 44 , NUMBER 11 NOVEMBER 19B2 '" ;. OREGON GEOLOGY OIL AND GAS NEWS (ISSN 0164-3304) Columbia County VOLUME 44, NUMBER 11 NOVEMBER 1982 Reichhold Energy Corporation drilled Adams 34-28 to a total depth of 2,572 ft. The well, in sec. 28, T. 7 N., R. 5 W., Published monthly by the State of Oregon Department of was abandoned as a dry hole in September. Geology and Mineral Industries (Volumes I through 40 were en­ The company will soon spud Libel 12-14 in the Mist gas titled The Ore Bin). field. The proposed 2,900-ft well is to be located in sec. 14, T. 6 N., R. 5 W .. The location is half a mile from the recently Governing Board completed redrill of Columbia County 4. C. Stanley Rasmussen ........................... Baker Allen P. Stinchfield ........................ North Bend Clatsop County Donald A. Haagensen. .. Portland Oregon Natural Gas Development Company's Patton 32-9 in sec. 9, T. 7 N., R. 5 W., is idle pending the decision State Geologist .. .. Donald A. Hull whether to redrill. Deputy State Geologist ..................... John D. Beaulieu Douglas County Editor .... .. Beverly F. Vogt Florida Exploration Company has abandoned the 1-4 well near Drain. It is not known whether the company will drill Main Ollice: 1005 State Office Building, Portland 97201, other locations. phone (503) 229-5580. Yamhill County Baker Field Office: 2033 First Street, Baker 97814, phone (503) Nahama and Weagant Energy Company recently drilled 523-3133. Klohs 1 in sec. 6, T.
    [Show full text]
  • A Geologic Study of the Capulin Volcano National Monument and Surrounding Areas, Union and Colfax Counties, New Mexico
    A Geologic Study of the Capulin Volcano National Monument and surrounding areas, Union and Colfax Counties, New Mexico by William O. Sayre and Michael H. Ort New Mexico Bureau of Geology and Mineral Resources, New Mexico Tech Socorro, New Mexico 87801 Open-file Report 541 August, 2011 A geologic study of Capulin Volcano National Monument and surrounding areas Final Report Cooperative Agreement CA7029-2-0017 December 4, 1999 Submitted to: Capulin Volcano National Monument P. O. Box 80 Capulin, New Mexico 88414 Submitted by: William O. Sayre, Ph.D., P.G. College of Santa Fe 1600 St. Michael’s Drive Santa Fe, New Mexico 87505-7634 and Michael H. Ort, Ph.D. Department of Geology PO Box 4099 Northern Arizona University Flagstaff, Arizona 86011 Table of Contents Executive Summary ........................................................................................................ 2 Introduction ..................................................................................................................... 2 Body of Report .............................................................................................................. 17 Discussion and Conclusions ......................................................................................... 22 Recommendations for Future Work .............................................................................. 64 References .................................................................................................................... 65 Appendices…………………………………………………………………………………….
    [Show full text]
  • Volcano ­ Accessscience from Mcgraw­Hill Education
    10/3/2016 Volcano ­ AccessScience from McGraw­Hill Education (http://www.accessscience.com/) Volcano Article by: Tilling, Robert I. Branch of Igneous and Geothermal Processes, U.S. Geological Survey, Menlo Park, California. Publication year: 2014 DOI: http://dx.doi.org/10.1036/1097­8542.735200 (http://dx.doi.org/10.1036/1097­8542.735200) Content Volcanic vents Volcanic products Volcanic landforms Submarine volcanism Fumaroles and hot springs Distribution of volcanoes Bibliography Additional Readings A mountain or hill, generally steep­sided, formed by accumulation of magma (molten rock with associated gas and crystals) erupted through openings or volcanic vents in the Earth's crust; the term volcano also refers to the vent itself. During the evolution of a long­lived volcano, a permanent shift in the locus of principal vent activity can produce a satellitic volcanic accumulation as large as or larger than the parent volcano, in effect forming a new volcano on the flanks of the old. Planetary exploration has revealed dramatic evidence of volcanoes and their products on extra­terrestrial bodies, such as the Earth's Moon, Mars, Mercury, Venus, and the moons of Jupiter (Fig. 1), Neptune, and Uranus on a scale much more vast than on Earth. For example, Olympus Mons, a gigantic shield volcano on Mars about 600 km (375 mi) in diameter, is larger across than the length of the Hawaiian Islands. However, only the products and landforms of terrestrial volcanic activity are described here. See also: Mars (/content/mars/407700); Mercury (planet) (/content/mercury­ planet/415700); Moon (/content/moon/434600); Neptune (/content/neptune/449000); Uranus (/content/uranus/722800); Venus (/content/venus/730100); Volcanology (/content/volcanology/735300) http://www.accessscience.com/content/volcano/735200 1/17 10/3/2016 Volcano ­ AccessScience from McGraw­Hill Education Fig.
    [Show full text]
  • Pre-Eruptive Storage Conditions and Eruption Dynamics of a Small Rhyolite Dome: Douglas Knob, Yellowstone Volcanic Field, USA
    Bull Volcanol (2014) 76:808 DOI 10.1007/s00445-014-0808-8 RESEARCH ARTICLE Pre-eruptive storage conditions and eruption dynamics of a small rhyolite dome: Douglas Knob, Yellowstone volcanic field, USA Kenneth S. Befus & Robert W.Zinke & Jacob S. Jordan & Michael Manga & James E. Gardner Received: 14 May 2013 /Accepted: 5 February 2014 # Springer-Verlag Berlin Heidelberg 2014 Abstract The properties and processes that control the size, ranging from 0.03 to 0.11 MPa h−1 (∼0.4–1.3 mm s−1 ascent duration, and style of eruption of rhyolite magma are poorly rates). Such slow ascent would allow time for passive constrained because of a paucity of direct observations. Here, degassing at depth in the conduit, thus resulting in an effusive we investigate the small-volume, nonexplosive end-member. eruption. Using calculated melt viscosity, we infer that the In particular, we determine the pre-eruptive storage conditions dike that fed the eruption was 4–8 m in width. Magma flux and eruption dynamics of Douglas Knob, a 0.011-km3 obsid- through this dike, assuming fissure dimensions at the surface ian dome that erupted from a 500-m-long fissure in the represent its geometry at depth, implies an eruption duration Yellowstone volcanic system. To determine pre-eruptive stor- of 17–210 days. That duration is also consistent with the shape age conditions, we analyzed compositions of phenocrysts, of the dome if produced by gravitational spreading, as well as matrix glass, and quartz-hosted glass inclusions by electron the ascent time of magma from its storage depth.
    [Show full text]
  • STATE of OREGON DEPARTMENT of GEOLOGY and MINERAL INDUSTRIES the Ore Bin Published Monthly By
    LiaR. Marine ace Laboratory Oregon State University Vol. 32, No. 6 June 1970 STATE OF OREGON DEPARTMENT OF GEOLOGY AND MINERAL INDUSTRIES The Ore Bin Published Monthly By STATE OF OREGON DEPARTMENT OF GEOLOGY AND MINERAL INDUSTRIES Head Office: 1069 State Office Bldg., Portland, Oregon - 97201 Telephone: 226 - 2161, Ext. 488 FIELD OFFICES 2033 First Street 521 N. E. "E" Street Baker 97814 Grants Pass 97526 XX X XX X X XX X X XX X X XX X X X Subscription rate $1.00 per year. Available back issues 10 cents each. Second class postage paid at Portland, Oregon 'X 'X' 'X' 'X 'X' 5Z 'X• 5Z 5Z 'X 5Z 5Z 5Z 5Z 5Z SZ 5Z 5Z 5r 'X GOVERNING BOARD Fayette I. Bristol, Rogue River, Chairman R. W. deWeese, Portland Harold Banta, Baker STATE GEOLOGIST R. E. Corcoran GEOLOGISTS IN CHARGE OF FIELD OFFICES Norman S. Wagner, Baker Len Ramp, Grants Pass 5Z 5Z 5Z 'k 5Z 5Z 'k 5Z 5Z 5Z 5Z 5Z 5Z 5Z 5Z Permission is granted to reprint information contained herein. Credit given the State of Oregon Department of Geology and Mineral Industries for compiling this information will be appreciated. • State of Oregon The ORE BIN Department of Geology Volume 32, No.6 and Mineral Industries June 1 970 1069 State Office Bldg. Portland Oregon 97201 CENOZOIC ASH-FLOW TUFFS OF OREGON* By George W. Walker U.S. Geological Survey, Menlo Park, California 94025. ABSTRACT Periodic violent eruptions from many different centers during Cenozoic time deposited vast quantities of pyroclastic material as ash-flow tuffs over most of Oregon, although the Coast Ranges and isolated patches elsewhere in the state appear to have been spared these recurring inundations.
    [Show full text]