HR: 1330h
AN: V42B-0351    [PDF]
TI: Monitoring Morphological Changes at Colima Volcano Crater and Explosive Activity in 2003
AU: * Suarez-Plascencia, C
EM: csuarez@cencar.udg.mx
AF: Depto. de Geografia/SisVoc U.de Guadalajara, M.Barcena y Av. de los Maestros, Guadalajara, Jal 44220 Mexico
AU: Nunez-Cornu, F
EM: fcornu@pv.udg.mx
AF: Depto. de Geografia/SisVoc U.de Guadalajara, M.Barcena y Av. de los Maestros, Guadalajara, Jal 44220 Mexico
AU: Reyes-Davila, G
EM: gard@cgic.ucol.mx
AF: RESCO U. de Colima, Av.G.de Sandoval 444, Colima, Col 28045 Mexico
AB: The Colima Volcano is located in the West of the Volcanic Mexican Belt, since February 10 1999 has presented an alternated efusive and explosive activity, which has generated constant morphological changes at the summit. As result of the several explosions occurred in 1999, 2000 and at the beginning of the year 2001, a new crater was formed with dimensions of 260 for 225 meters, and an average depth of 40 m. This crater began to be filled by the end of October 31, 2001 by a extrusion dome that reach an approximate volume 2 x 106 m3. In the first week of February 2002 this dome reach the edge of the crater, beginning to form lava flows by the western, northeastern, and south flanks. This effusive activity continued in 2002, and small gas emission and explosions were observed. In April 2003 the number of explosions and degassings became more frequent in the dome, this activity was registred by the seismic networks (RESCO and RESJAL) and recorded by video cameras located at Jalisco Civil Defense Nevado Base, 5 km away of the volcano. Aerial reconnaissance carried out in May 16 showed a complete change in the morphology of the dome as was observed in February 2002, identifying a new crater with a elipsoidal concave shape with approximate dimensions of 140 x 110 m and a depth in its central part of 15 mts. In the SE flank we observed another crater with similar form to the previous one whose dimensions are of 30 x 20 m with depth of 15 m, where continuous explosions have been appraised. At dawn of June 17, August 2 and 28, 2003 explosions happened that reached an altitude between 2000 and 3000 m, which were of smaller magnitude than happened the 22 of February of the 2000. These explosions were preceded of prolonged periods of tremor reported by RESCO. This explosive activity also present gas emission gas in form of jets, with duration from some seconds until more a than minute and altitude of approximate 500 meters, like the occurred on June 7, its point of emission was located in the crater of the SE sector. The eruptive columns begin to reach greater heights, since the conduit offers less resistance to the outgoing of material and gas, since the seismic energy released is smaller each time, most of the energy is concentrating in the exhalation. As a result of this explosive activity, we observed in the last aerial reconnaissance an important change in the morphology in the summit in relation to the observed in the month of May. The crater reaches approximate dimensions of 160 x 120 m, and a depth of approximately 30 m. The edges of the dome present an irregular morphology and a series of heterometrics blocks launched by the constant explosions.
DE: 7280 Volcano seismology (8419)
DE: 8419 Eruption monitoring (7280)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting