Layana, S., Aguilera, F., Inostroza, M. et al. (6 more authors) (2023) Evolution of the magmatic-hydrothermal system at Lastarria volcano (Northern Chile) between 2006 and 2019: insights from fluid geochemistry. Frontiers in Earth Science, 11. 1114001. ISSN 2296-6463
Abstract
One of the major problems in the volcanic surveillance is how data from several techniques can be correlated and used to discriminate between possible precursors of volcanic eruptions and changes related to non-eruptive processes. Gas chemical surveys and measurements of SO2 emission rates performed in the past (2006–2019) at Lastarria volcano in Northern Chile have revealed a persistent increment of magmatic sourced gas emissions since late November 2012, following a 13 years period of intense ground uplift. In this work, we provide new insights into the gas-chemical evolution of Lastarria’s fumarolic discharges obtained from direct sampling (2006–2019) and SO2 emission rates using UV camera and DOAS instruments (2018–2019) and link these to pre-existing information on ground deformation (1998–2016) in order to determine the origin of observed degassing and ground deformation processes. We revise the four mechanisms originally proposed as alternatives by Lopez et al. (Geosphere, 2018, 14 (3), 983–1007) to explain the changes observed in the fluid geochemistry and ground deformation between 2009 and 2012, in order to explain major changes in gas-geochemistry over an extended period between 1998 and 2019. We hypothesize that a continuous sequence of processes explains the evolution in the fluid geochemistry of fumarolic discharges. Two mechanisms are responsible of the changes in the gas composition during the studied period, corresponding to a 1) deep magma chamber (7–15 km depth) pressurized by volatile exsolution (1998–2020), which is responsible of the large-scale deformation; followed by 2) a crystallization-induced degassing (2001–2020) and pressurization of the hydrothermal system (2003-early November 2012), where the former process induced the changes in the gas composition from hydrothermal-dominated to magmatic-dominated, whereas the last produced the small-scale deformation at Lastarria volcano. The changes in the gas composition since late November 2012, which were strongly dominated by magmatic volatiles, produced two consecutive processes: 1) acidification (late November 2012–2020) and 2) depletion (2019–2020) of the hydrothermal system. In this work we have shown that a long-term surveillance of the chemistry of fluid discharges provides valuable insights into underlying magmatic/volcanic processes, and consequently, for forecasting future eruptions.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2023 Layana, Aguilera, Inostroza, Tassi, Wilkes, Bredemeyer, González, Pering and McGonigle. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. https://creativecommons.org/licenses/by/4.0/ |
Keywords: | volcanic degassing; volatile flux; central volcanic zone of the andes; PiCam; ground-based remote gas measurements; direct sampling |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Social Sciences (Sheffield) > Department of Geography (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 10 May 2023 15:47 |
Last Modified: | 10 May 2023 15:47 |
Status: | Published |
Publisher: | Frontiers Media SA |
Refereed: | Yes |
Identification Number: | 10.3389/feart.2023.1114001 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:199030 |