DOCSLIB.ORG

Hot Rocks and Oil: Are Volcanic Margins the New Frontier?

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hot Rocks and Oil: Are Volcanic Margins the New Frontier? FOR OIL & GAS ARTICLE Hot Rocks and Oil: Are Volcanic Margins the New Frontier? ASSESSING THE CHALLENGES AND OPPORTUNITIES OF FINDING AND EXTRACTING NATURAL RESOURCES FROM A VOLATILE ENVIRONMENT By Dougal A. Jerram Hot rocks and oil: Are volcanic margins the new frontier? VISITING MODERN VOLCANOES: LEARNING FROM PAST AND PRESENT Volcanoes evoke a classic image of a cone-shaped mountain exploding ash, or rivers of molten rock. The lure of the volcano is almost primordial. Looking back into the Earth’s past volcanic events—including some of nature’s most beautiful volcanoes and eruptions in the present (e.g., Bárðarbunga, Iceland; Stromboli, Italy; Pu`u `O`o, Hawaii - see Figure 1)—can shed light on the active cooling planet and the role volcanoes played in Earth’s evolution1. Figure 1: Understanding modern volcanic systems; a) recent volcanic activity at Bárðarbunga with fissure eruptions which fed lava flows (Sept 2014), b) sampling at the front of the advancing lava where it is diverting a meltwater river (Sept 2014), c) sampling lava flows at Hawaii1, d) the volcano Stromboli erupting at sunset1. Every new volcanic eruption is a real-time opportunity to capture exactly what happens over time and allows researchers to examine the resultant lava flows, explosive ash horizons and other deposits. The spectacular Bárðarbunga, for instance, provided examples of the erup- tion entering and diverting a modern river system that came down from the ice cap (e.g. Figure 1b). This eruption also became the largest in Iceland for over 200 years with the lava field covering 85 km², and an erupted volume of 1.4 km³ of new lava2. Older rock masses also provide clues of where ancient volcanic episodes occurred, their timing and their relationship to surrounding rocks and Earth history. Modern systems provide the key to understanding the past volcanic events, and geoscientists use the ancient dissected systems to help them understand what happens within and beneath volcanoes as they build volcanic constructions. 2 Examining modern volcanoes and the ancient volcanic past can offer insights into the relationships between volcanic rocks, the sediment/petroleum systems associated with them and the exploration potential in volcanic basins – between hot rocks and oil. Seeing how modern sedimentary systems interact with volcanic eruptions and the resultant deposits provides a direct view of how both competing processes act on one another. Studying the ancient deposits preserved in onshore segments of volcanic systems also allows analogues to be drawn with offshore exploration targets3. These insights, when applied with other research findings, can improve the understanding of exploration plays, reduce risk and lead to better outcomes. The next stage is to investigate the role of volcanic margins in present and future natural resource exploration. WHAT ARE VOLCANIC MARGINS AND WHY MIGHT THEY BE IMPORTANT FOR NATURAL RESOURCE EXPLORATION? Many of the sedimentary basins that have accumulated the rocks that can create, trans- port and store oil and gas in the subsurface have also been the sites of major volcanic episodes in Earth’s history. At punctuated stages in the past there have been large volcanic eruptions, termed ‘flood basalts’, which have been responsible for millions of cubic kilometres of erupted rocks, and similar amounts of frozen magma, stored in the plumbing systems beneath these ancient volcanoes. These events leave footprints on the Earth’s surface known as large igneous provinces (LIPs)4. These flood basalts and their magma feeding systems are often found intricately associ- ated with some of the major sedimentary basins. A look at the world map (Figure 2) with indicated basins and volcanics paints this picture5, and helps geoscientists define areas where exploration of the sediments will be affected by volcanic rocks along ‘volca- nic margins’. Hydrocarbons, as well as aquifer reservoirs, occur in many of these prospective volcanic basins. It is believed that many more exist and are yet to be discovered. Figure 2. World map highlighting the main mafic large igneous provinces, sedimentary basins and the volcanic basins where there is a good association of the LIPs with sedimentary basins4, 5. 3 ISSUES WITH VOLCANIC ROCKS AND EXPLORATION In order to get an oil or gas prospect one needs what is known as the ‘5 steps to heaven’. 1. Reservoir – the rock mass that has void space to host the hydrocarbon. 2. Seal – a rock that is impermeable to the migration of hydrocarbons. 3. Trap – a structure/orientation of rock strata that will trap the migration of hydrocarbons to the surface. 4. Source – an organic-rich sediment that will mature with burial and lead to the production of hydrocarbons (e.g. organic shales, coal, etc.). 5. Timing/migration – the set of events that allows the maturation and migration of the hydrocarbons to occur after the trap is in place so that they are successfully fed into the reservoir. How these ‘5 steps to heaven’ are found in a volcanic basin will depend on the timing of the volcanic events, the intrusion of the magma through the sediments and the development of traps prior to any charging of hydrocarbons. Hot magma can, in principle, act as a heat source to mature the petroleum system. For the most part, thick igneous rocks are thought to have reasonably good sealing properties. It is also known from exposed rock sequences that volcanic rocks can have a variety of shapes and geometries that create traps. Volcanic rocks, however, are unlikely to be source rocks as they do not contain organic material. So the volcanic system—from intrusions through the basins to the eruptions at the sur- face—can contribute multiple scenarios that can lead to a working hydrocarbon prospect6,7. The most common volcanic margins are those found at rifting settings. This setting can be used to further explore what types of exploration targets may be available. A schematic vol- canic rifted margin is presented as a 3D model and in cross-section in Figure 3 (with various aspects of the potential petroleum system highlighted in Figure 3b)5. Mixed sequences of hydro volcanic and lava flows are found along with associated sills and dykes which form the plumbing systems of the volcanic margins underneath. These systems develop where the rifting apart of continents coincides with flood basalt volcanism and creates LIPs. With continued rifting, the volcanic deposits are preserved on either side of the rifted continents. Examples of these are the North and South Atlantic margins with the North Atlantic Igneous Province (NAIP) and the Parana-Etendeka Province (see map in Figure 2)8. In the rifted volcanic margin model, hydrocarbon reservoirs can be found in common styles of trap (e.g. structural, stratigraphic, etc.) in structures and sediments that are above (supra) or below (sub) the volcanics. The volcanic rocks might not have influenced the prospect, but may now cause imaging and drilling concerns. The emplacement of the volcanics through their plumbing systems of dykes and sill can create fluid migration pathways where hydro- carbons are channelled. This can create structures where hydrocarbons may be trapped. The intrusion of the hot magma into organic rich sediments may also affect and enhance the maturation, leading to the generation of hydrocarbons. A picture, therefore, develops where the presence of significant volcanic material can both hinder and be advantageous depending on the circumstances. There is a certain asymme- try to the distribution of the volcanic and intrusive rocks in this rifted margin model. The amount and thickness of the units change from very minor — in parts of the basins where only the sills are found — to much thicker, where the thick lava sequences and associated sills are found (e.g., Figure 3b). The existing and potential exploration into these thicker zones, however, can prove prob- lematic. Technical issues include imaging within and beneath the volcanics and the prospect of drilling through thick lava flows. 4 Figure 3. Volcanic rifted margins; a) schematic 3D cartoon of the development of a typical volcanic margin, b) the resultant cross-section of a typical volcanic rifted margin (e.g. NE Atlantic Margin), with volcanic facies and possible hydrocarbon traps and migration pathways indicated5. IMAGING BENEATH VOLCANICS In order to confidently explore the subsurface, successfully imaging possible hydrocarbon targets is important. This is where volcanic rocks provide a specific problem, often termed the ‘Sub-Basalt Imaging’ problem9. Volcanic intervals in the subsurface, usually thick sequences of basalt but can also include relatively thin horizons, often masks the rock units below. When imaging the Earth’s interior with seismic waves, the volcanic units contain high velocity horizons, a massive range in high to low velocity in repeated cycles within the volcanic stratigraphy. They can have markedly irregular surfaces and geometries compared to simple flat sediments. All of these factors can reduce the transmission of seismic energy below, provide increased noise and also lead to ‘false’ layers/structures (multiples) in the data. Oil and gas companies looking to drill in these challenging areas need as much ‘visible’ data as possible before deciding whether to engage. 5 Two possible solutions to the Sub-Basalt Imaging problem are to: 1. Find better ways to process existing data to emphasize the signal that one gets in the ‘sub-basalt’ domain. 2. Better design and plan new acquisitions where thick volcanic sequences are known to present a challenge. Improvements in acquiring new data include: 1. The position and recording of the seismic source at specific depths in the water. 2. The types of source fired. 3. The types and position of the receivers used. For example: long offset arrays of receivers, bespoke 3D seismic surveys and even ocean bottom situated seismometers. These are all designed to reduce the amount of noise and enhance low frequency data, which is known to penetrate through the volcanics.
Load more

Recommended publications
  • Volcanic Gases and Aerosols Guidelines Introduction
    IVHHN Gas Guidelines www.ivhhn.org/gas/guidelines.html Volcanic Gases and Aerosols Guidelines The following pages contain information relating to the health hazards of gases and aerosols typically emitted during volcanic activity. Each section outlines the properties of the emission; its impacts on health; international guidelines for concentrations; and examples of concentrations and effects in volcanic contexts, including casualties. Before looking at the emissions data, we recommend that you read the general introduction to volcanic gases and aerosols first. A glossary to some of the terms used in the explanations and guidelines is also provided at the end of this document. Introduction An introduction to the aims and purpose of the Gas and Aerosol Guidelines is given here, as well as further information on international guideline levels and the units used in the website. A brief review of safety procedures currently implemented by volcanologists and volcano observatories is also provided. General Introduction Gas and aerosol hazards are associated with all volcanic activity, from diffuse soil gas emissions to 2- plinian eruptions. The volcanic emissions of most concern are SO2, HF, sulphate (SO4 ), CO2, HCl and H2S, although, there are other volcanic volatile species that may have human health implications, including mercury and other metals. Since 1900, there have been at least 62 serious volcanic-gas related incidents. Of these, the gas-outburst at Lake Nyos in 1986 was the most disastrous, causing 1746 deaths, >845 injuries and the evacuation of 4430 people. Other volcanic-gas related incidents have been responsible for more than 280 deaths and 1120 injuries, and contributed to the evacuation or ill health of >53,700 people (Witham, in review).
    [Show full text]
  • GY 111: Physical Geology
    UNIVERSITY OF SOUTH ALABAMA GY 111: Physical Geology Lecture 9: Extrusive Igneous Rocks Instructor: Dr. Douglas W. Haywick Last Time 1) The chemical composition of the crust 2) Crystallization of molten rock 3) Bowen's Reaction Series Web notes 8 Chemical Composition of the Crust Element Wt% % of atoms Oxygen 46.6 60.5 Silicon 27.7 20.5 Aluminum 8.1 6.2 Iron 5.0 1.9 Calcium 3.6 1.9 Sodium 2.8 2.5 Potassium 2.6 1.8 Magnesium 2.1 1.4 All other elements 1.5 3.3 Crystallization of Magma http://myweb.cwpost.liu.edu/vdivener/notes/igneous.htm Bowen’s Reaction Series Source http://www.ltcconline.net/julian Igneous Rock Composition Source: http://hyperphysics.phy-astr.gsu.edu Composition Formation Dominant Silica content Temperature Minerals Ultramafic Very high Olivine, pyroxene Very low (<45%) Mafic High Olivine, pyroxene, low Ca-plagioclase Intermediate Medium Na-Plagioclase, moderate amphibole, biotite Felsic Medium-low Orthoclase, quartz, high (>65%) muscovite, biotite Igneous Rock Texture Extrusive Rocks (Rapid Cooling; non visible* crystals) Intrusive Rocks (slow cooling; 100 % visible crystals) *with a hand lens Igneous Rock Texture Igneous Rock Texture Today’s Agenda 1) Pyro-what? (air fall volcanic rocks) 2) Felsic and Intermediate Extrusive Rocks 3) Mafic Extrusive Rocks Web notes 9 Pyroclastic Igneous Rocks Pyroclastic Igneous Rocks Pyroclastic: Pyro means “fire”. Clastic means particles; both are of Greek origin. Pyroclastic Igneous Rocks Pyroclastic: Pyro means “fire”. Clastic means particles; both are of Greek origin. Pyroclastic rocks are usually erupted from composite volcanoes (e.g., they are produced via explosive eruptions from viscous, “cool” lavas) Pyroclastic Igneous Rocks Pyroclastic: Pyro means “fire”.
    [Show full text]
  • Deep Carbon Emissions from Volcanoes Michael R
    Reviews in Mineralogy & Geochemistry Vol. 75 pp. 323-354, 2013 11 Copyright © Mineralogical Society of America Deep Carbon Emissions from Volcanoes Michael R. Burton Istituto Nazionale di Geofisica e Vulcanologia Via della Faggiola, 32 56123 Pisa, Italy [email protected] Georgina M. Sawyer Laboratoire Magmas et Volcans, Université Blaise Pascal 5 rue Kessler, 63038 Clermont Ferrand, France and Istituto Nazionale di Geofisica e Vulcanologia Via della Faggiola, 32 56123 Pisa, Italy Domenico Granieri Istituto Nazionale di Geofisica e Vulcanologia Via della Faggiola, 32 56123 Pisa, Italy INTRODUCTION: VOLCANIC CO2 EMISSIONS IN THE GEOLOGICAL CARBON CYCLE Over long periods of time (~Ma), we may consider the oceans, atmosphere and biosphere as a single exospheric reservoir for CO2. The geological carbon cycle describes the inputs to this exosphere from mantle degassing, metamorphism of subducted carbonates and outputs from weathering of aluminosilicate rocks (Walker et al. 1981). A feedback mechanism relates the weathering rate with the amount of CO2 in the atmosphere via the greenhouse effect (e.g., Wang et al. 1976). An increase in atmospheric CO2 concentrations induces higher temperatures, leading to higher rates of weathering, which draw down atmospheric CO2 concentrations (Ber- ner 1991). Atmospheric CO2 concentrations are therefore stabilized over long timescales by this feedback mechanism (Zeebe and Caldeira 2008). This process may have played a role (Feulner et al. 2012) in stabilizing temperatures on Earth while solar radiation steadily increased due to stellar evolution (Bahcall et al. 2001). In this context the role of CO2 degassing from the Earth is clearly fundamental to the stability of the climate, and therefore to life on Earth.
    [Show full text]
  • Insights Into the Recurrent Energetic Eruptions That Drive Awu Among the Deadliest Volcanoes on Earth
    Insights into the recurrent energetic eruptions that drive Awu among the deadliest volcanoes on earth Philipson Bani1, Kristianto2, Syegi Kunrat2, Devy Kamil Syahbana2 5 1- Laboratoire Magmas et Volcans, Université Blaise Pascal - CNRS -IRD, OPGC, Aubière, France. 2- Center for Volcanology and Geological Hazard Mitigation (CVGHM), Jl. Diponegoro No. 57, Bandung, Indonesia Correspondence to: Philipson Bani ([email protected]) 10 Abstract The little known Awu volcano (Sangihe island, Indonesia) is among the deadliest with a cumulative death toll of 11048. In less than 4 centuries, 18 eruptions were recorded, including two VEI-4 and three VEI-3 eruptions with worldwide impacts. The regional geodynamic setting is controlled by a divergent-double-subduction and an arc-arc collision. In that context, the slab stalls in the mantle, undergoes an increase of temperature and becomes prone to 15 melting, a process that sustained the magmatic supply. Awu also has the particularity to host alternatively and simultaneously a lava dome and a crater lake throughout its activity. The lava dome passively erupted through the crater lake and induced strong water evaporation from the crater. A conduit plug associated with this dome emplacement subsequently channeled the gas emission to the crater wall. However, with the lava dome cooling, the high annual rainfall eventually reconstituted the crater lake and created a hazardous situation on Awu. Indeed with a new magma 20 injection, rapid pressure buildup may pulverize the conduit plug and the lava dome, allowing lake water injection and subsequent explosive water-magma interaction. The past vigorous eruptions are likely induced by these phenomena, a possible scenario for the future events.
    [Show full text]
  • Volcano Hazards at Newberry Volcano, Oregon
    Volcano Hazards at Newberry Volcano, Oregon By David R. Sherrod1, Larry G. Mastin2, William E. Scott2, and Steven P. Schilling2 1 U.S. Geological Survey, Hawaii National Park, HI 96718 2 U.S. Geological Survey, Vancouver, WA 98661 OPEN-FILE REPORT 97-513 This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 1997 U.S. Department of the Interior U.S. Geological Survey CONTENTS Introduction 1 Hazardous volcanic phenomena 2 Newberry's volcanic history is a guide to future eruptions 2 Flank eruptions would most likely be basaltic 3 The caldera would be the site of most rhyolitic eruptions—and other types of dangerously explosive eruptions 3 The presence of lakes may add to the danger of eruptions in the caldera 5 The most damaging lahars and floods at Newberry volcano would be limited to the Paulina Creek area 5 Small to moderate-size earthquakes are commonly associated with volcanic activity 6 Volcano hazard zonation 7 Hazard zone for pyroclastic eruptions 7 Regional tephra hazards 8 Hazard zone for lahars or floods on Paulina Creek 8 Hazard zone for volcanic gases 10 Hazard zones for lava flows 10 Large-magnitude explosive eruptions of low probability 11 Monitoring and warnings 12 Suggestions for further reading 12 Endnotes 13 ILLUSTRATIONS Plate 1. Volcano hazards at Newberry volcano, Oregon in pocket Figure 1. Index map showing Newberry volcano and vicinity 1 Figure 2.
    [Show full text]
  • Origins of High-Temperature Fluids in the Goshogake Mud Volcano Field, Tohoku, Northern Japan: Chemical and Isotopic Studies of Gas and Water
    49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083) 1210.pdf ORIGINS OF HIGH-TEMPERATURE FLUIDS IN THE GOSHOGAKE MUD VOLCANO FIELD, TOHOKU, NORTHERN JAPAN: CHEMICAL AND ISOTOPIC STUDIES OF GAS AND WATER. R. Ishimaru1, N. Miyake1, G. Komatsu2, K. Kawai3, M. Kobayashi4, H. Sakuma5, T. Matsui1 1Planetary Exploration Research Center (PERC), Chiba Institute of Technology (Chitech) (2-17-1 Tsudanuma, Narashino, Chiba 275-0016, Japan; [email protected]), 2International Research School of Planetary Sciences, Università d'Annunzio (Viale Pindaro 42, 65127 Pescara, Italy), 3Department of Earth and Planetary Science, School of Science, University of Tokyo (Hongo 7-3-1, Bunkyo, Tokyo 113-0033, Japan), 4Department of Earth and Planetary Environmental Sci- ence, School of Science, University of Tokyo (Hongo 7-3-1, Bunkyo, Tokyo 113-0033, Japan), 5Reseach Center for Functional Materials, National Institute for Materials Science (1-1 Namiki, Tsukuba, 305-0044 Japan). Introduction: Mud volcanoes occur everywhere Gas sampling and laboratory analysis. Gases were in various geological settings on the Earth [e.g., 1] and, collected with a custom-made sampling device for possibly, on other planetary bodies, such as Mars [e.g., laboratory measurement of the gas species. The com- 2] and Enceladus ocean floor. Their surface terrains position analysis of the gas samples in the chamber are formed by mud ascending and erupting, together was conducted using Gas Chromatography (GS) in the with water and gas, from depths. Therefore, mud vol- laboratory. The GC analyses are made in two ways: cano is one of the most suitable landforms for explor- qualitative and quantitative analyses.
    [Show full text]
  • 1998 Volcanic Activity in Alaska and Kamchatka: Summary of Events and Response of the Alaska Volcano Observatory by Robert G
    1998 Volcanic Activity in Alaska and Kamchatka: Summary of Events and Response of the Alaska Volcano Observatory by Robert G. McGimsey, Christina A. Neal, and Olga Girina Open-File Report 03-423 U.S. Department of the Interior U.S. Geological Survey 1998 Volcanic Activity in Alaska and Kamchatka: Summary of Events and Response of the Alaska Volcano Observatory By Robert G. McGimsey1, Christina A. Neal1, and Olga Girina2 1Alaska Volcano Observatory, 4200 University Dr., Anchorage, AK 99508-4664 2Kamchatka Volcanic eruptions Response Team, Institute of Volcanic Geology and Geochemistry, Piip Blvd., 9 Petropavlovsk-Kam- chatsky, 683006, Russia AVO is a cooperative program of the U.S. Geological Survey, University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys. AVO is funded by the U.S. Geological Survey Volcano Hazards Program and the State of Alaska Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government Open-File Report 03-423 U.S. Department of the Interior U.S. Geological Survey TABLE OF CONTENTS Introduction. 1 Reports of volcanic activity, northeast to southwest along Aleutian arc . 4 Shrub Mud Volcano . 4 Augustine Volcano . 6 Becharof Lake Area . 8 Chiginagak Volcano . 10 Shishaldin Volcano. 12 Akutan Volcano . 12 Korovin Volcano . 13 Reports of Volcanic activity, Kamchatka, Russia, North to South . 15 Sheveluch Volcano . 17 Klyuchevskoy Volcano. 19 Bezymianny Volcano . 21 Karymsky Volcano . 23 References. 24 Acknowledgments . 26 Figures 1 A. Map location of historically active volcanoes in Alaska and place names used in this summary .
    [Show full text]
  • One Hundred Volatile Years of Volcanic Gas Studies at the Hawaiian Volcano Observatory
    Characteristics of Hawaiian Volcanoes Editors: Michael P. Poland, Taeko Jane Takahashi, and Claire M. Landowski U.S. Geological Survey Professional Paper 1801, 2014 Chapter 7 One Hundred Volatile Years of Volcanic Gas Studies at the Hawaiian Volcano Observatory By A. Jeff Sutton1 and Tamar Elias1 The smell of sulphur is strong, but not unpleasant to Kīlauea’s summit, together with surface-deformation and a sinner. other data, detected an increase in deep magma supply more than a year before a corresponding surge in effusive activity. —Mark Twain, Letters from Hawaii, 1866 Correspondingly, HVO routinely uses SO2 emissions to study shallow eruptive processes and effusion rates. HVO gas studies and Kīlauea’s long-running East Rift Zone eruption also demonstrate that volatile emissions can be a substantial Abstract volcanic hazard in Hawai‘i. From its humble beginning, trying to determine the chemical composition of volcanic The first volcanic gas studies in Hawai‘i, beginning gases over a century ago, HVO has evolved to routinely use in 1912, established that volatile emissions from Kīlauea real-time gas chemistry to track eruptive processes, as well Volcano contained mostly water vapor, in addition to as hazards. carbon dioxide and sulfur dioxide. This straightforward discovery overturned a popular volatile theory of the day and, in the same action, helped affirm Thomas A. Jaggar, Introduction Jr.’s, vision of the Hawaiian Volcano Observatory (HVO) as a preeminent place to study volcanic processes. Decades later, the environmental movement produced a watershed Volcanic gases are a dominating force in eruptive of quantitative analytical tools that, after being tested activity.
    [Show full text]
  • Volcanic SO2 Emissions and the Abundance and Distribution of Exsolved Gas in Magma Bodies
    Journal of Volcanologyand Geothermal Research 108 2001) 85±106 www.elsevier.com/locate/jvolgeores Volcanic SO2 emissions and the abundance and distribution of exsolved gas in magma bodies P.J. Wallace* Ocean Drilling Program, Texas A & M University, College Station, TX 77845, USA Abstract The mass of sulfur dioxide SO2) released bymost explosive volcanic eruptions greatlyexceeds the amount originally dissolved in the erupted volume of silicate melt. Several lines of evidence suggest that this discrepancyis due to the presence of SO2-bearing gas bubbles in the magma before the time of eruption. Comparison of remote sensing data for SO2 emissions with conventional petrologic estimates suggests that the discrepancycan be resolved if andesitic and dacitic magmas contain about 1±6 wt% exsolved gas, equivalent to 5±30 vol%, prior to eruption. Such large mass fractions of exsolved gas in pre-eruptive magma are consistent with previously published physical models in which crystallization-induced gas exsolution gradually increases overpressuring of a magma reservoir, eventuallytriggering an eruption. Simple mass balance models for SO 2 emissions from magma bodies in which there is an upwards increasing gradient in exsolved gas mass fraction i.e. gas-rich at the top) yield SO2 vs. eruptive volume trends that are similar to those observed for eruptions ranging in size from 0.01 to 10 km3 of magma. Despite the manyuncertainties involved, these patterns are consistent with the hypothesisthat subvolcanic magma reservoirs are separated from volcanic vents bycupolas of gas-rich magma that supplymuch of the gas released in explosive eruptions. The volume fraction of exsolved gas inferred from SO2 data for the upper regions of manypre-eruptive magma bodies ,30 vol%) is similar to the percolation threshold at which gas bubbles become suf®cientlyinterconnected to allow permeable gas ¯ow through a bubble network.
    [Show full text]
  • Chemical Composition of a Mud Volcano LUSI and the Health Risk
    Sains Malaysiana 47(8)(2018): 1665–1674 http://dx.doi.org/10.17576/jsm-2018-4708-05 Chemical Composition of a Mud Volcano LUSI and the Health Risk Involved based on the Air Quality Index that Occurred as a Result of Disastrous Gas Exploration Drilling Activities in Sidoarjo, Indonesia (Komposisi Kimia daripada Gunung berapi LUSI dan Risiko Kesihatan yang Terlibat Berdasarkan Indeks Kualiti Udara Hasil daripada Aktiviti Penggerudian Eksplorasi Gas Bencana di Sidoarjo, Indonesia) DEWI HIDAYATI, ISMAIL B.S., SHUHAIMI-OTHMAN M. & NORELA SULAIMAN* ABSTRACT LUSI (Lumpur“mud”-Sidoarjo) is the mud volcanic which was initiated by the failed gas drilling exploration activities carried out near an urban area. The evaluation of the LUSI mud volcanic emission and its dried mud effects on air pollution and human health was carried out from 2011 to 2012. The concentrations of particulate matter (PM2.5), hazardous gases (H2S, SO2, NO2), volatile organic compounds (VOC): Including total hydrocarbons (THC)), toluene (C6H5CH3) and benzene (C6H6) as well as heavy metals (Pb, Cr and Cd) were measured following standard methods. The results showed 3 that the average concentration of PM2.5 ranged from 24.0-399.9 μg/m , H2S: 1.53-2.92 ppm; SO2: 0.021-1.321 ppm and NO2: 0.007-0.076 ppm. The VOC included total hydrocarbons from 0.57-0.96 ppm, toluene 0.33-0.92 ppm and benzene 0.33-0.40 ppm. Furthermore, heavy metal concentrations were as follows: Pb 2.6-37.34 μg/m3; Cr 0.14-12.8 μg/m3 and 3 Cd 0.78-4.16 μg/m .
    [Show full text]
  • Volatile Metal Emissions from Volcanic Degassing and Lava–Seawater
    ARTICLE https://doi.org/10.1038/s43247-021-00145-3 OPEN Volatile metal emissions from volcanic degassing and lava–seawater interactions at Kīlauea Volcano, Hawai’i ✉ Emily Mason 1 , Penny E. Wieser 1, Emma J. Liu 2, Marie Edmonds 3, Evgenia Ilyinskaya 4, Rachel C. W. Whitty5, Tamsin A. Mather 5, Tamar Elias 6, Patricia Amanda Nadeau 6, Thomas C. Wilkes 7, Andrew J. S. McGonigle7, Tom D. Pering7, Forrest M. Mims 8, Christoph Kern 9, David J. Schneider10 & Clive Oppenheimer 11 Volcanoes represent one of the largest natural sources of metals to the Earth’s surface. 1234567890():,; Emissions of these metals can have important impacts on the biosphere as pollutants or nutrients. Here we use ground- and drone-based direct measurements to compare the gas and particulate chemistry of the magmatic and lava–seawater interaction (laze) plumes from the 2018 eruption of Kīlauea, Hawai’i. We find that the magmatic plume contains abundant volatile metals and metalloids whereas the laze plume is further enriched in copper and seawater components, like chlorine, with volatile metals also elevated above seawater con- centrations. Speciation modelling of magmatic gas mixtures highlights the importance of the S2− ligand in highly volatile metal/metalloid degassing at the magmatic vent. In contrast, volatile metal enrichments in the laze plume can be explained by affinity for chloride com- plexation during late-stage degassing of distal lavas, which is potentially facilitated by the HCl gas formed as seawater boils. 1 Department of Earth Sciences, University of Cambridge, Cambridge, UK. 2 Department of Earth Sciences, University College London, London, UK.
    [Show full text]
  • The Volcanology Revolution
    Feature NURUL HIDAYAT/ANTARA FOTO/BISNIS INDONESIA VIA REUTERS FOTO/BISNIS HIDAYAT/ANTARA NURUL When Anak Krakatau in Indonesia erupted on 22 December 2018, part of the island collapsed into the ocean, causing a deadly tsunami. THE VOLCANOLOGY REVOLUTION Forty years after the Mount St Helens eruption galvanized volcano science, researchers are harnessing powerful new tools to forecast and understand eruptions. By Jane Palmer arly in 2018, the volcano Anak Krakatau the mountain began showing obvious signs of killed at least 430 people along the nearby in Indonesia started falling apart. It was unrest. It spewed fiery ash and rocks into the sky coasts of Java and Sumatra. Although nobody a subtle transformation — one that in a series of small eruptions. And it was heating foresaw that disaster, a 2019 study found that nobody noticed at the time. The south- up. Another satellite instrument recorded ther- satellite and ground-based instruments had ern and southwestern flanks of the vol- mal emissions from Anak Krakatau that reached picked up a suite of precursory signals that cano were slipping towards the ocean 146 megawatts — more than 100 times the could help forecast similar events in the future at a rate of about 4 millimetres per normal value. With the increased activity, the at Anak Krakatau and other peaks. month, a shift so small that research- slippage jumped to 10 millimetres per month. The unexpected collapse at Anak Krakatau Eers only saw it after the fact as they combed Then, on 22 December, the southern flank shows some of the challenges facing research- through satellite radar data.
    [Show full text]