HR: 1400h
AN: S43B-03 [Abstracts]
TI: Determination of a three-dimensional velocity structure for the Southeastern of Mexico, by means of seismic ray tracing.
AU: * Rodriguez-Perez, Q
EM: quetza81@hotmail.com
AF: Intituto de gepfisica, Ciudad Universitaria.
Del Coyoacán, Mexico, DF 04510, Mexico
AU: Valdes-Gozalez, C
EM: carlosv@ollin.igeofcu.unam.mx
AF: Intituto de gepfisica, Ciudad Universitaria.
Del Coyoacán, Mexico, DF 04510, Mexico
AB:
The objective of the present study is to obtain a three-dimensional velocity structure for three different tectonic
provinces (Oaxaca, Chiapas and north of Guatemala). The Southeastern of Mexico is a seismic active region, in
which several geologic structures of great importance are located: the Tehuantepec ridge, the Central-American
volcanic arc, the Chiapas batholit, the extension of the Motagua-Polochic fault system, and also the existance of
complex tectonostratigrafic terrenes at cortical level. In this area of study, there are a considerable number of
tectonic studies and cortical velocity models (1D). For this reason is desired to obtain a three-dimensional
realistic velocity model that agrees with the results obtained in previous studies. To make it posible, a preliminary
velocity model has been proposed and has been discretized, and is now at the test stage. Also the geometry of
the Cocos plate is determined (variation of the subduction angle) and we will try to obtain the interaction between
the Motagua-Polochic fault system and the previously described subduction provinces. We will use P and S
waves, from local and regional earthquakes from 1994 to 2004 reported by National Seismological Service (SSN)
in eight broadband seismic stations in the Southeastern of Mexico (CCIG, CMIG, EVV, HUIG, OXIG, SCX TPX,
TUIG). In the study earthquake relocalizations with the DD method will be performed, and a 3-D ray tracing will be
used to test the seismic model. The 3-D velocity model will allow us to better understand the wave propagation
characteristics, and apply them to the mitigation of the seismic risk in the region.
1. Earth Science Graduate Program. UNAM.
2. Institute of Geophysics. UNAM.
DE: 1207 Transient deformation (6924, 7230, 7240)
DE: 1219 Gravity anomalies and Earth structure (0920, 7205, 7240)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 7240 Subduction zones (1207, 1219, 1240)
SC: Seismology [S]
MN: 2007 Joint Assembly