HR: 1340h
AN: V33B-1467    [Abstracts]
TI: Detection of SO2, HCl and CO2 in Arenal Volcano Eruptive Plume Using MASTER Multispectral Images
AU: Bonatti, J
EM: jbonatti2000@yahoo.com
AF: CICANUM. Universidad de Costa Rica, San Pedro de Montes de Oca, Ciudad Universitaria Rodrigo Facio, San Jos‚, 2060 Costa Rica
AU: Berrocal, M
EM: milena03cr@yahoo.com.mx
AF: OVSICORI. Universidad Nacional, Universidad Nacional, Heredia, 86-3000 Costa Rica
AU: * Malavassi, E
EM: emalava@una.ac.cr
AF: OVSICORI. Universidad Nacional, Universidad Nacional, Heredia, 86-3000 Costa Rica
AB: The Costa Rica Airborne Research and Technology Applications (CARTA) Mission developed in March-April, 2003 was a join effort between the National Program for Airtransported Missions of the National Center for High Technology of Costa Rica formed by the four public universities in Costa Rica, and NASA. This mission took aerial infrared photography and multiespectral images using the MASTER sensor of 70% of the national territory of Costa Rica. Multiespectral images were taken from Arenal volcano at high (13780 m) and at low (3450 m) altitude. The MASTER images have an aperture ranging between 0.44 micrometers in the visible and 13 micrometers in the thermic infrared. In addition, the distribution of the 50 channels of the MASTER sensor, have been arranged to avoid the influence of water vapor, always present in large quantities in the atmosphere and also in volcanic gases. We determined that SO2 is clearly visible between 8.5-9.3 micrometers (LWIR), and CO2, H2S and HCl in a smaller bandwidth 3.5-4.4 micrometers (MWIR). Another gas detected at Arenal volcanic plumes is methane, in a bandwidth between 7.7-8.1 micrometers (LWIR). When both multispectral images were taken, Arenal volcano had an active lava flow descending its NE flank and no significative winds were blowing, so the eruptive plume was rising almost vertically from the active vent. Profiles of gas concentration collected from the above mentioned bands were performed on the image using the software ENVI to detect different species present in volcanic gases. The concentration of volcanic gases in the multiespectral image was largest above the active crater (north vent of Crater C), and lower on the short active lava flow whose blocks were cascading down up to 1 km on the NE flank. Significant amounts of SO2 were measured above the lava flow and the fan of cascading blocks suggesting that the cooling lava continues to release magmatic gases as their cascading blocks move down flank of the volcano. The higher resolution of the low altitude multispectral image assured better results when measuring volcanic gas species.
DE: 7280 Volcano seismology (8419)
DE: 3630 Experimental mineralogy and petrology
DE: 1040 Isotopic composition/chemistry
DE: 1065 Trace elements (3670)
DE: 1299 General or miscellaneous
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting