HR: 0800h
AN: V41B-0605    [Abstracts]
TI: ANOMALOUS EMISSIONS OF SULFUR DIOXIDE AND SEISMICITY OF SAN MIGUEL VOLCANO, EL SALVADOR IN OCTOBER, 2006
AU: * Olmos, R
EM: rolmos99@yahoo.com
AF: Rodolfo Olmos, Consejo de Investigaciones Científicas. Universidad de El Salvador. El Salvador. C. America, San salvador, 1908,
AU: Barahona, F
EM: barahona_escoto@yahoo.es
AF: Rodolfo Olmos, Consejo de Investigaciones Científicas. Universidad de El Salvador. El Salvador. C. America, San salvador, 1908,
AU: Hernández, A
EM: agusthdc@yahoo.es
AF: Rodolfo Olmos, Consejo de Investigaciones Científicas. Universidad de El Salvador. El Salvador. C. America, San salvador, 1908,
AU: Cartagena, R
EM: el_ali_@yahoo.com
AF: Rodolfo Olmos, Consejo de Investigaciones Científicas. Universidad de El Salvador. El Salvador. C. America, San salvador, 1908,
AU: Henríquez, B
EM: benancio62@yahoo.com
AF: Rodolfo Olmos, Consejo de Investigaciones Científicas. Universidad de El Salvador. El Salvador. C. America, San salvador, 1908,
AU: López, D
EM: lopezd@ohio.edu
AF: Dina López, Department of Geological Sciences, Ohio University, Athens, OH 45701- 2979, USA, Ohio, 216,
AU: Cárdenas, C
EM: claudia.rivera@rss.chalmers.se
AF: Claudia Cárdenas, Consejo de Investigaciones Científicas. Universidad Department of Radio and Space Science, University of Chalmers, Gothenburg, Swedende El Salvador, San Salvador, 412,
AU: Galle, B
EM: bo.galle@rss.chalmers.se
AF: Claudia Cárdenas, Consejo de Investigaciones Científicas. Universidad Department of Radio and Space Science, University of Chalmers, Gothenburg, Swedende El Salvador, San Salvador, 412,
AB: San Miguel (also known as Chaparrastique) volcano in eastern El Salvador is located 15 km southwest of the city of San Miguel. This volcano has erupted more than 30 times since 1699, with the last gas and ash emission on January 16, 2002. During 2006, San Miguel presented anomalous gas emissions and seismicity. In this work, the seismic parameters reported by SNET (Servicio Nacional de Estudios Territoriales de El Salvador) and the crater gas emissions measured by researchers of the University of El Salvador are compared. For the gas efflux, two types of measurements were done using the Mini-DOAS system (Galle et al., 2002): transects around the crater perimeter (~100 m) and transects following roads located between 5 and 10 km from the crater. Several measurements between October 2005 and May 2006 indicate that the sulfur dioxide efflux during quiet periods is around 20 ton/day. From May to June 2006, a progressive increase in fumarolic activity and noise from gas emissions were observed. From May to August 2006, the sulfur dioxide emissions increased to 60 ton/day. A seismic crisis started on October 9, 2006, increasing the RSAM from 10-20 to 208 on October 10, 2006. During this time, the sulfur dioxide efflux reached a maximum of 492 ton/day. This increase in sulfur dioxide efflux represents 25 times the basic emissions during the previous quiet period and 8 times the values observed from May to August 2006. The correlation coefficient between sulfur dioxide efflux and RSAM values during this period of time was 0.81, which is statistically significant at a level higher than 99.9% . These anomalous changes in seismicity and sulfur dioxide emissions at San Miguel volcano suggest a magmatic reactivation with an increase in the exsolution of magma volatiles, long period seismic events, and volcanic tremor.
DE: 8419 Volcano monitoring (7280)
DE: 8430 Volcanic gases
DE: 8485 Remote sensing of volcanoes
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting