HR: 1400h
AN: G33A-05    [Abstracts]
TI: Slow slip events in the Mexican subduction zone (Guerrero-Oaxaca) observed by the analysis of continuous GPS
AU: * Cotte, N
EM: ncotte@obs.ujf-grenoble.fr
AF: LGIT CNRS - Université Joseph Fourier, CNRS - UJF Maison des Géosciences - BP53, Grenoble, 38041, France
AU: Walpersdorf, A
EM: awalpers@obs.ujf-grenoble.fr
AF: LGIT CNRS - Université Joseph Fourier, CNRS - UJF Maison des Géosciences - BP53, Grenoble, 38041, France
AU: Kostoglodov, V
EM: vladi@servidor.unam.mx
AF: Instituto de Geofisica - UNAM, Ciudad Universitaria Del. Coyoacan, Mexico, DF 04510, Mexico
AU: Vergnolle, M
EM: mathilde.vergnolle@obs.ujf-grenoble.fr
AF: LGIT CNRS - Université Joseph Fourier, CNRS - UJF Maison des Géosciences - BP53, Grenoble, 38041, France
AU: Santiago, J
EM: santiago@geofisica.unam.mx
AF: Instituto de Geofisica - UNAM, Ciudad Universitaria Del. Coyoacan, Mexico, DF 04510, Mexico
AB: Aseismic slow slip events (SSE) have been observed in the last decade with GPS, in particular in the Mexican subduction zone, Guerrero-Oaxaca. Thanks to the effort of the UNAM (Universidad Nacional Autonoma de Mexico), 21 permanent GPS stations are currently operating within or close to this zone. We present the results of an analysis of the available continuous GPS data that we have conducted using the Gamit/Globk softwares developped by MIT (Massachusetts Institute of Technology) and SIO (Scripps Institution of Oceanography). The analysis includes up to date atmospheric loading models and mapping functions, what helps us to gain more precision in the positioning results. We have analyzed the complete time series running from 1997 (first GPS station installed in Cayaco) up to present. One of our major objectives is to study the time evolution of the slow slip events and to determine the amplitude and the direction of the slips. A first major result from our analysis is that we do not find in the time series any clear evidence of a number of the smallest transient slip events (i.e., total displacements of 1-2 cm at the coast) that had been reported before in Guerrero-Oaxaca and we suggest that some of them may actually be artefacts.
DE: 1207 Transient deformation (6924, 7230, 7240)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
DE: 7240 Subduction zones (1207, 1219, 1240)
SC: Geodesy [G]
MN: 2007 Joint Assembly