Unrest at the Nevados de Chillán volcanic complex: a failed or yet to unfold magmatic eruption?
Resuming erupting activity at volcanoes that have been long quiescent poses a significant challenge to hazard assessment, as it require assessment of whether the change in activity is an isolated event or the beginning of a new eruptive sequence. Such inception is often poorly characterised as quies...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Volcanica
2018-05-01
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| Series: | Volcanica |
| Subjects: | |
| Online Access: | https://www.jvolcanica.org/ojs/index.php/volcanica/article/view/7 |
| _version_ | 1818878475908415488 |
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| author | Yves Moussallam Philipson Bani C. Ian Schipper Carlos Cardona Luis Franco Talfan Barnie Álvaro Amigo Aaron Curtis Nial Peters Alessandro Aiuppa Gaetano Giudice Clive Oppenheimer |
| author_facet | Yves Moussallam Philipson Bani C. Ian Schipper Carlos Cardona Luis Franco Talfan Barnie Álvaro Amigo Aaron Curtis Nial Peters Alessandro Aiuppa Gaetano Giudice Clive Oppenheimer |
| author_sort | Yves Moussallam |
| collection | DOAJ |
| description | Resuming erupting activity at volcanoes that have been long quiescent poses a significant challenge to hazard assessment, as it require assessment of whether the change in activity is an isolated event or the beginning of a new eruptive sequence. Such inception is often poorly characterised as quiescent volcanoes tend to be poorly equipped and not extensively monitored, especially with respect to gas geochemistry. Here, we report gas composition and flux measurements from a newly opened vent at the very onset of eruptive activity at the Nevados de Chillán volcanic complex (Chile) in January-February 2016. The molar proportions of H2O, CO2, SO2, H2S and H2 gases are found to be 98.4, 0.97, 0.11, 0.01 and 0.5 mol% respectively. The mean SO2 flux recorded in early February 2016 during periods of eruptive discharge amounts to 0.4-0.6 kg s-1. Our results indicate that the new vent opening was propelled by magmatic gases, triggering repeated eruptions. Ash particles ejected by the first blast of 8 January are dominated by lithic fragments of dacitic composition. By contrast the ash ejected in a subsequent eruption contains both lithic fragments of dense dacite, and a fresher, sparsely vesicular material of basaltic andesite composition. By October 2017 the ejected ash is back to being dominated by the dense dacitic lithic material. Together with the seismic and deformation record, these observations point to the explosive activity resulting from a small intrusion of basaltic to andesitic magma at shallow level. The fate of this magma, whether stalling or eventually triggering a magmatic eruption, remains to be seen, but current observations suggest the former is most likely. |
| first_indexed | 2024-12-19T14:14:47Z |
| format | Article |
| id | doaj.art-54b39aaa28b14e66958147b138f6787f |
| institution | Directory Open Access Journal |
| issn | 2610-3540 |
| language | English |
| last_indexed | 2024-12-19T14:14:47Z |
| publishDate | 2018-05-01 |
| publisher | Volcanica |
| record_format | Article |
| series | Volcanica |
| spelling | doaj.art-54b39aaa28b14e66958147b138f6787f2022-12-21T20:18:00ZengVolcanicaVolcanica2610-35402018-05-0111193210.30909/vol.01.01.19327Unrest at the Nevados de Chillán volcanic complex: a failed or yet to unfold magmatic eruption?Yves Moussallam0Philipson Bani1C. Ian Schipper2Carlos Cardona3Luis Franco4Talfan Barnie5Álvaro Amigo6Aaron Curtis7Nial Peters8Alessandro Aiuppa9Gaetano Giudice10Clive Oppenheimer11Université Clermont AuvergneUniversité Clermont AuvergneVictoria University of WellingtonObservatorio Vulcanológico de los Andes del SurObservatorio Vulcanológico de los Andes del SurNordic Volcanological CenterObservatorio Vulcanológico de los Andes del SurJet Propulsion Laboratory - California Institute of TechnologyUniversity of CambridgeUniversità di PalermoIstituto Nazionale di Geofisica e VulcanologiaUniversity of CambridgeResuming erupting activity at volcanoes that have been long quiescent poses a significant challenge to hazard assessment, as it require assessment of whether the change in activity is an isolated event or the beginning of a new eruptive sequence. Such inception is often poorly characterised as quiescent volcanoes tend to be poorly equipped and not extensively monitored, especially with respect to gas geochemistry. Here, we report gas composition and flux measurements from a newly opened vent at the very onset of eruptive activity at the Nevados de Chillán volcanic complex (Chile) in January-February 2016. The molar proportions of H2O, CO2, SO2, H2S and H2 gases are found to be 98.4, 0.97, 0.11, 0.01 and 0.5 mol% respectively. The mean SO2 flux recorded in early February 2016 during periods of eruptive discharge amounts to 0.4-0.6 kg s-1. Our results indicate that the new vent opening was propelled by magmatic gases, triggering repeated eruptions. Ash particles ejected by the first blast of 8 January are dominated by lithic fragments of dacitic composition. By contrast the ash ejected in a subsequent eruption contains both lithic fragments of dense dacite, and a fresher, sparsely vesicular material of basaltic andesite composition. By October 2017 the ejected ash is back to being dominated by the dense dacitic lithic material. Together with the seismic and deformation record, these observations point to the explosive activity resulting from a small intrusion of basaltic to andesitic magma at shallow level. The fate of this magma, whether stalling or eventually triggering a magmatic eruption, remains to be seen, but current observations suggest the former is most likely.https://www.jvolcanica.org/ojs/index.php/volcanica/article/view/7Volcanic unrestEruption triggerUV cameraMulti-GASTrail By FireVolcanic gases |
| spellingShingle | Yves Moussallam Philipson Bani C. Ian Schipper Carlos Cardona Luis Franco Talfan Barnie Álvaro Amigo Aaron Curtis Nial Peters Alessandro Aiuppa Gaetano Giudice Clive Oppenheimer Unrest at the Nevados de Chillán volcanic complex: a failed or yet to unfold magmatic eruption? Volcanica Volcanic unrest Eruption trigger UV camera Multi-GAS Trail By Fire Volcanic gases |
| title | Unrest at the Nevados de Chillán volcanic complex: a failed or yet to unfold magmatic eruption? |
| title_full | Unrest at the Nevados de Chillán volcanic complex: a failed or yet to unfold magmatic eruption? |
| title_fullStr | Unrest at the Nevados de Chillán volcanic complex: a failed or yet to unfold magmatic eruption? |
| title_full_unstemmed | Unrest at the Nevados de Chillán volcanic complex: a failed or yet to unfold magmatic eruption? |
| title_short | Unrest at the Nevados de Chillán volcanic complex: a failed or yet to unfold magmatic eruption? |
| title_sort | unrest at the nevados de chillan volcanic complex a failed or yet to unfold magmatic eruption |
| topic | Volcanic unrest Eruption trigger UV camera Multi-GAS Trail By Fire Volcanic gases |
| url | https://www.jvolcanica.org/ojs/index.php/volcanica/article/view/7 |
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