HR: 11:50h
AN: V12B-07    [Abstracts]
TI: Systematic gas flux cycles observed using very high temporal resolution DOAS and UV camera imagery at Santiaguito Volcano, Guatemala.
AU: * Watson, I M
EM: matt.watson@bristol.ac.uk
AF: Department of Earth Sciences, University of Bristol, Queen's Road, Bristol, BS8 1JR, United Kingdom
AU: * Watson, I M
EM: matt.watson@bristol.ac.uk
AF: Department of Geological and Mining Engineering and Sciences, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931-1295, United States
AU: Branan, Y K
EM: ykbranan@iup.edu
AF: Department of Geological and Mining Engineering and Sciences, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931-1295, United States
AU: Branan, Y K
EM: ykbranan@iup.edu
AF: Geoscience department, Indiana University of Pennsylvania, 1011 South Drive, Indiana, PA 15705-1085, United States
AU: Smekens, J
EM: jf.smekens@bristol.ac.uk
AF: Department of Earth Sciences, University of Bristol, Queen's Road, Bristol, BS8 1JR, United Kingdom
AU: Phillips, J C
EM: J.C.phillips@bristol.ac.uk
AF: Department of Earth Sciences, University of Bristol, Queen's Road, Bristol, BS8 1JR, United Kingdom
AU: Holland, P
EM: holland.asp@googlemail.com
AF: Department of Earth Sciences, University of Bristol, Queen's Road, Bristol, BS8 1JR, United Kingdom
AB: Cyclic gas production has been observed at Santiaguito volcano, Guatemala, using differential optical absorption spectroscopy (DOAS) and UV imaging systems. Santiaguito explodes regularly, on the order of once an hour, and produces weak ash plumes, that are mostly buoyancy driven, to an altitude of 1-2 km above its dome. Dara from campaigns in 2004-2006 yield striking similarities in the production of SO2 across an explosive cycle. This is only observable due to the instruments' rapid data acquisition of no more than a few seconds per measurement. There is an initial increase in output associated with the explosion (more than 2 kg per second SO2) which quickly returns to ‘background' levels (between 0.1-0.5 kg per second SO2). These background levels vary systematically between explosions and have a sinusoidal pattern. Normalization of the gas flux to a constant rise rate indicates the maximum passive output occurs at approximately 0.4-0.7 cycles which is followed by a significant drop in emission rate before the next explosion. These methods have the potential to provide real predictive capability at Santiaguito and provide insight into shallow processes governing gas production and release in quasi-open systems. Three potential mechanisms exist to explain the length of time the system requires to reset – (i) pistoning associated with unsteady flow, (ii) resealing of cracks and subsequent pressurization and (iii) defluidisation of the porous cap after perturbation. Each has its own merits and issues when explaining the observed gas cyles.
DE: 8419 Volcano monitoring (7280)
DE: 8428 Explosive volcanism
DE: 8430 Volcanic gases
DE: 8434 Magma migration and fragmentation
DE: 8485 Remote sensing of volcanoes
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting