HR: 1340h
AN: T13C-1482    [Abstracts]
TI: Seismic Pattern of the Guerrero-Oaxaca, Mexico Region and its Relationship to the Continental Margin Structure
AU: * Yamamoto, J
EM: yamas@ollin.igeofcu.unam.mx
AF: Instituto de Geofisica Universidad Nacional Autonoma de Mexico, Ciudad Universitaria Coyoacan, Mexico, DF 04510, Mexico
AU: Gonzalez-Moran, T
EM: tglez@geofisica.unam.mx
AF: Instituto de Geofisica Universidad Nacional Autonoma de Mexico, Ciudad Universitaria Coyoacan, Mexico, DF 04510, Mexico
AB: The purpose of this article is to make aware seismic evidences that suggest a possible segmentation of the continental margin at the Guerrero-Oaxaca, Mexico region. A survey of microseismicity using a portable seismographs network and the analysis of the aftershocks distribution of 1982 and 1995 major earthquakes permit to infer the characteristics of the seismic patterns of the Acapulco-Pinotepa segment of the Middle America subduction region. Two different seismic regimes are apparent, one in the Acapulco-Marquelia and another in the Marquelia-Pinotepa areas. In the Acapulco-Marquelia segment the seismicity is disperse and broader it starts at the coast up to 160 km inland approximately. Seismicity in the Marquelia-Pinotepa segment on the other hand, is narrower and concentrates near the coast. The seismic zones are separated by two narrow bands of low seismic activity nearly perpendicular to the coast and trench axis. These two low activity strips, located near the northern tip of the Ometepec submarine canyon and Punta Maldonado respectively, are interpreted in the present paper as corresponding to disruptions of the continental margin. Supplementary geophysical information in this area seems to additionally substantiate this interpretation. This result is important to understand the mechanics of the major earthquakes that frequently occur in this region.
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7240 Subduction zones (1207, 1219, 1240)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting