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SO2 degassing at Tu...
SO2 degassing at Tungurahua volcano (Ecuador) between 2007 and 2013: Transition from continuous to episodic activity
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- Hidalgo, Silvana (author)
- Escuela Politécnica Nacional
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Battaglia, Jean (author)
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- Arellano, Santiago, 1981 (author)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Steele, Alex (author)
- Escuela Politécnica Nacional
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- Bernard, Benjamin (author)
- Escuela Politécnica Nacional
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- Bourquin, Julie (author)
- Escuela Politécnica Nacional
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- Galle, Bo, 1952 (author)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Arrais, Santiago (author)
- Escuela Politécnica Nacional
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- Vásconez, Freddie (author)
- Escuela Politécnica Nacional
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(creator_code:org_t)
- Elsevier BV, 2015
- 2015
- English.
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In: Journal of Volcanology and Geothermal Research. - : Elsevier BV. - 0377-0273. ; 298, s. 1-14
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Abstract
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- We present continuous SO2 measurements performed at Tungurahua volcano with a permanent network of 4 scanning DOAS instruments between 2007 and 2013. The volcano has been erupting since September 1999, but on the contrary to the first years of eruption when the activity was quasi-continuous, the activity transitioned in late 2008 towards the occurrence of distinct eruptive phases separated by periods of quiescence. During our study period we distinguish 11 phases lasting from 17 to 527days separated by quiescence periods of 26 to 184days. We propose a new routine to quantify the SO2 emissions when data from a dense DOAS monitoring network are available. This routine consists in summing all the highest validated SO2 measurements among all stations during the 10h of daily working-time to obtain a daily observed SO2 mass. Since measurement time is constant at Tungurahua the "observed" amounts can be expressed in tons per 10h and can easily be converted to a daily average flux or mass per day. Our results provide time series having an improved correlation on a long time scale with the eruptive phases and with quiescence periods. A total of 1.25Mt (1.25×109kg) of SO2 has been released by Tungurahua during the study period, with 95% of these emissions occurring during phases of activity and only 5% during quiescence. This shows a contrast with previous volcanic behaviour when passive degassing dominated the total SO2 emissions. SO2 average daily mass emission rates are of 73±56t/d during quiescent periods, 735±969t/d during long-lasting phases and 1424±1224t/d during short-lasting phases. Degassing during the different eruptive phases displays variable patterns. However, two contrasting behaviours can be distinguished for the onset of eruptive phases with both sudden and progressive onsets being observed. The first is characterised by violent opening of the conduit by high energy Vulcanian explosions; and the second by a progressive, in crescendo, development of the activity. The first case is becoming more frequent at Tungurahua making the volcano more dangerous and less predictable.
Subject headings
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Annan geovetenskap och miljövetenskap (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Other Earth and Related Environmental Sciences (hsv//eng)
Keyword
- SO2 degassing
- Episodic volcanic
- Open and closed system behaviour
- Tungurahua
- DOAS
- Activity
Publication and Content Type
- art (subject category)
- ref (subject category)
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- By the author/editor
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Hidalgo, Silvana
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Battaglia, Jean
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Arellano, Santia ...
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Steele, Alex
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Bernard, Benjami ...
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Bourquin, Julie
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show more...
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Galle, Bo, 1952
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Arrais, Santiago
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Vásconez, Freddi ...
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show less...
- About the subject
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- NATURAL SCIENCES
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NATURAL SCIENCES
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and Earth and Relate ...
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and Other Earth and ...
- Articles in the publication
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Journal of Volca ...
- By the university
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Chalmers University of Technology