Anomalous Soil Temperature and CO<sub>2</sub> Emissions at Cerro Pacho (Coatepeque Caldera) and Santa Ana Volcano before the October 1, 2005 Eruption of Santa Ana Volcano

HR: 0800h
AN: V41A-04 [Abstracts]
TI: Anomalous Soil Temperature and CO₂ Emissions at Cerro Pacho (Coatepeque Caldera) and Santa Ana Volcano before the October 1, 2005 Eruption of Santa Ana Volcano
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. Norte, Ciudad Universitaria, San Salvador, El Salvador
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. Norte, Ciudad Universitaria, 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. Norte, Ciudad Universitaria, 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. Norte, Ciudad Universitaria, 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. Norte, Ciudad Universitaria, 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. Norte, Ciudad Universitaria, 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: Coatepeque Caldera and Santa Ana Volcano belong to the Santa Ana-Izalco-Coatepeque volcanic complex in western El Salvador. The last eruption of Santa Ana Volcano on October 1, 2005 killed two people and damaged 65% of the cultivated land around the volcano due to ash emissions and gases. Prior and after the eruption, we carry out several CO₂ soil efflux and soil temperature surveys of Cerro Pacho fumarolic field and Santa Ana Volcano crater. For the diffuse CO₂ emission, at Cerro Pacho the total CO₂ efflux emited to the atmosphere from an area of 2600 m² on April 1, September 7, and October 26, 2005, was 77, 99 and 64 kg/day respectively. In comparison, at the south-east perimeter of Santa Ana Crater, CO₂ emissions on September 2 and September 21, 2005, were 112 and 442 g/m² day, respectively (Barahona et al.,2007,this meeting). These values are one order of magnitude higher than the 15 g/m² day measured in the same region by Salazar et al. (2004). For the soil temperatures at Cerro Pacho and at the south of Santa Ana crater, three areas of temperatures higher than 60°C were identified. According to Allis (1979), for soil temperatures lower than 60°C the dominant heat transport mechanism is conductive, there is a transition zone between 60-70°C, and the convective zone occurs at temperatures higher than 70°C up to the boiling point. At Santa Ana crater and at Cerro Pacho, the temperature anomalies were oriented in the NW-SE and E-W direction. In Santa Ana crater, the conductive zone was more important with a 49.1% of the surveyed area on May 8, and a 57% on April 7, 2005. This increase in convective heat flow suggest an increase in thermal heat from the volcano. At Cerro Pacho we have only a slight difference of 90 to 92% in the conductive area during April 3 and October 26, 2005, respectively. The increase in diffuse soil CO₂ and the variations in the thermal field at the Santa Ana Crater and the Cerro Pacho fumarolic field can be interpreted as premonitory signals of the Santa Ana Volcano eruption. At other active volcanoes, monitoring of the soil temperature and diffuse emissions of gases could be important methods to follow the state of activity of a volcano.
DE: 8419 Volcano monitoring (7280)
DE: 8430 Volcanic gases
SC: Volcanology, Geochemistry, and Petrology [V]
MN: 2007 Joint Assembly