HR: 0800h
AN: V41A-06    [Abstracts]
TI: Pre and Post-Eruptive Variations in Diffuse Soil CO₂ Degassing at the Crater Rim of Santa Ana Volcano, El Salvador, Central America
AU: * Barahona, F
EM: barahona_escoto@yahoo.es
AF: Consejo de Investigaciones Científicas. Universidad de El Salvador. El Salvador. C. America, Universidad de El Salvador, Autopista Norte y Final 25 Av., San Salvador, El Salvador
AU: Olmos, R
EM: rolmos99@yahoo.com
AF: Consejo de Investigaciones Científicas. Universidad de El Salvador. El Salvador. C. America, Universidad de El Salvador, Autopista Norte y Final 25 Av., San Salvador, El Salvador
AU: Henríquez, B
EM: benancio62@yahoo.com
AF: Consejo de Investigaciones Científicas. Universidad de El Salvador. El Salvador. C. America, Universidad de El Salvador, Autopista Norte y Final 25 Av., San Salvador, El Salvador
AU: Hernández, A
EM: agusthdc@yahoo.es
AF: Consejo de Investigaciones Científicas. Universidad de El Salvador. El Salvador. C. America, Universidad de El Salvador, Autopista Norte y Final 25 Av., San Salvador, El Salvador
AU: Benítez, J
EM: dleone67@yahoo.es
AF: Consejo de Investigaciones Científicas. Universidad de El Salvador. El Salvador. C. America, Universidad de El Salvador, Autopista Norte y Final 25 Av., San Salvador, El Salvador
AU: Funes, R
EM: renanfunes@yahoo.com
AF: Consejo de Investigaciones Científicas. Universidad de El Salvador. El Salvador. C. America, Universidad de El Salvador, Autopista Norte y Final 25 Av., San Salvador, El Salvador
AU: López, D
EM: lopezd@ohio.edu
AF: Department of Geological Sciences, Ohio University, Athens, Oh 45701, USA, Athens, OH , United States
AU: Hernández, P
EM: phdez@iter.es
AF: Enviromental Research Division, ITER, 38611 Granadilla, Tenerife, Canary Island, Spain
AU: Pérez, N
EM: nperez@iter.es
AF: Enviromental Research Division, ITER, 38611 Granadilla, Tenerife, Canary Island, Spain
AB: Santa Ana volcano, in western El Salvador, Central America, erupted on October 1st, 2005. Before and after the eruption, this volcano has been monitored seismically, with measurements of diffuse fluxes of soil gases and measurements of SO₂ emissions in the volcanic plume. In 2001, a survey of diffuse soil CO₂ around the crater found only very low or non-detectable values of diffuse soil CO₂ (Salazar. et., al 2001). After signs of in this volcano, a profile of diffuse emissions of CO₂ around a portion of the crater rim was monitored. This profile covers an arc of 65 m along the SE of the crater, in a zone that did not show emissions of CO₂ in 2001. 13 observation points were selected for this discrete monitoring in seven different dates, three before and four after the eruption. The measurements were done using the accumulation chamber method (Chiodini.,et al, 1998) and an infrared spectrometer Licor LI-820. The results show that the average, maximum, and minimum fluxes for the entire profile increased around one order of magnitude for the period between August 31st and September 21, 2005, with highest measured values in September 21st. The mean, maximum and minimum values were 442, 1439 and 5 g/m²d, respectively, on that day. The mean, maximum and minimum fluxes presented the lowest values in February 28, 2006, with values of 8 g/m²d for the mean, 40 g/m²d for the maximum and non-detectable for the minimum. After February 28, the flux of CO₂ has presented only small. These observations show that Santa Ana is in a period of minimum emission of diffuse gases due to a relatively low activity as compared with the August-September, 2005 activity. This work shows how important it is to monitor the diffuse soil gases in discrete mode for the detection of early signals of volcanic reactivation. This observations together with seismic monitoring and the monitoring of plume gases seem to be a promising methodology for the forecast of volcanic eruptions.
DE: 8419 Volcano monitoring (7280)
DE: 8430 Volcanic gases
SC: Volcanology, Geochemistry, and Petrology [V]
MN: 2007 Joint Assembly