HR: 14:00h
AN: U53A-01    [Abstracts]
TI: Results From GPS Observations: No Evidence for Displacement Along the Polochic Fault in Southeastern Mexico
AU: * Guzman-Speziale, M
EM: marco@geociencias.unam.mx
AF: Centro de Geociencias, UNAM, Campus UNAM Juriquilla, Queretaro, Qro 76230, Mexico
AU: Kostoglodov, V
EM: vladi@servidor.unam.mx
AF: Instituto de Geofisica, UNAM, Ciudad Universitaria, Mexico, DF 04510, Mexico
AU: Manea, M
EM: marina@geociencias.unam.mx
AF: Centro de Geociencias, UNAM, Campus UNAM Juriquilla, Queretaro, Qro 76230, Mexico
AU: Manea, V
EM: vlad@geociencias.unam.mx
AF: Centro de Geociencias, UNAM, Campus UNAM Juriquilla, Queretaro, Qro 76230, Mexico
AB: From 2000 to 2005 we performed GPS observations in nine sites (occupational) in southeastern Mexico. At the same time, french colleagues measured 24 sites in Guatemala. We obtained displacement vectors, with respect to a stable North America and with respect to a no-net-rotation frame of reference (ITRF2000). In Guatemala, where the trace of the fault has a well-defined surface trace, displacement vecors agree well with a left-lateral relative displacement along the fault. In southeastern Mexico, the trace of the fault is uncertain and the observed displacement vectors do not correspond to a left-lateral displacement, as predicted in earlier models. Our results show displacement vectors oriented in a NNE direction with respect to North America, and in a NW direction in the ITRF2000 reference frame. This suggests a clockwise rotation of the block located just to the northeast of where the fault trace ends. Some authors have suggested that such rotation takes place at the terminus of a strike-slip fault. Therefore, we suggest that Polochic fault actually ends where its surface trace dissapears, in the Mexico-Guatemala border.
DE: 1209 Tectonic deformation (6924)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 8158 Plate motions: present and recent (3040)
SC: Union [U]
MN: 2007 Joint Assembly