HR: 0800h
AN: V41D-0799    [Abstracts]
TI: A Study of the Source Processes of Colima Volcano Explosions
AU: * Nunez-Cornu, F J
EM: pacornu77@gmail.com
AF: Centro de Sismologia y Volcanologia de Occidente. Univ. de Guadalajara, Universidad 203, Puerto Vallarta, Jal 48280, Mexico
AU: Vargas-Bracamontes, D
AF: Institute of Geophysics and Tectonics, University of Leeds, Leeds, UK LS29JT, United Kingdom
AU: Sanchez, J J
AF: Centro de Sismologia y Volcanologia de Occidente. Univ. de Guadalajara, Universidad 203, Puerto Vallarta, Jal 48280, Mexico
AU: Suarez-Plascencia, C
AF: Centro de Sismologia y Volcanologia de Occidente. Univ. de Guadalajara, Universidad 203, Puerto Vallarta, Jal 48280, Mexico
AB: Colima volcano, considered as Mexico's most active volcano, has presented several intermittent effusive and explosive phases in recent years. During 2005, a sequence of explosive events with VEI less than or equal to 3 occurred. This activity presented the most intense explosions since the seismic network was deployed. Many of the explosive events were recorded by the digital three-component seismic stations operated by the University of Guadalajara and Jalisco State Civil Defense. These signals were recorded not only by stations located on the volcanic edifice, but also by stations on the northern coast of Jalisco (MCUJ, BSSJ) and Ceboruco Volcano at 184, 182 and 200 km distance, respectively. A study of these signals will be presented. Each explosion was preceded by a seismic event. Nevertheless, the located earthquakes preceding the explosions did not show a common source under the volcano structure, which suggests the existence of a complex structure with possibly more than one conduit, this is also confirmed from a first motion analysis for station F03J, located 12 km at north of the volcano. From analysis of the first ten seconds of the seismic signal on F03J using different representations of the seismic signals, such as waveforms, spectra, time-frequency and time-scale analysis, it is suggested that the source processes are non-stationary, implying that for the case of this period, a general model of the source process of the Colima volcano explosions can not be formulated. The size of the events is evaluated using different criteria. A clear relation between the magnitude of the seismic signals and the amplitude of the sonic and infrasonic waves was not observed.
DE: 7280 Volcano seismology (8419)
DE: 8413 Subduction zone processes (1031, 3060, 3613, 8170)
DE: 8414 Eruption mechanisms and flow emplacement
DE: 8419 Volcano monitoring (7280)
DE: 8488 Volcanic hazards and risks
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting