HR: 1340h
AN: T33B-0553    [Abstracts]
TI: Is Baja California part of the Pacific Plate?
AU: * Plattner, C
EM: plattner@geophysik.uni-muenchen.de
AF: Ludwig Maximilians University of Munich, Department of Geophysics Theresienstr. 41, Muenchen, 80333 Germany
AU: Malservisi, R
T33B-0553 AF: Ludwig Maximilians University of Munich, Department of Geophysics Theresienstr. 41, Muenchen, 80333 Germany
AU: Malservisi, R
T33B-0553 AF: RSMAS University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149-1098 United States
AU: Dixon, T H
T33B-0553 AF: RSMAS University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149-1098 United States
AU: Lafemina, P C
T33B-0553 AF: RSMAS University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149-1098 United States
AU: Schmalzle, G
T33B-0553 AF: RSMAS University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149-1098 United States
AU: Fletcher, J
T33B-0553 AF: CICESE, Km. 107 Carretera Tijuana Ensenada, Ensenada, BC 2732 Mexico
AU: Suarez-Vidal, F
T33B-0553 AF: CICESE, Km. 107 Carretera Tijuana Ensenada, Ensenada, BC 2732 Mexico
AB: Coupling GPS observations with numerical modeling we can answer this important question and evaluate the effect of a non-complete coupling on the kinematics of the Western hemisphere. Until 12 Ma the western coast of Baja California (BC) was the location of the subduction of the Pacific plate (PA) underneath the North American plate (NA). It is a common assumption that the eastward migration of the plate boundary was complete ~3.6Ma and that since that time the Gulf of California has accommodate the full relative motion between North America and Pacific. One of the main consequences of this assumption is that the magnetic anomalies in the Gulf of California allow estimating the average relative motion between NA and PA. On the other hand, published geodetic measurement (e.g. Sella et al, 2000) indicate that NA is moving respect to PA at an higher rate then estimated by the spreading rate (DeMets et al 1994) and the few published GPS measurements in the Baja California Peninsula (Dixon and DeMets 1999, Dixon et al 2000, Dixon et al. 2001, Beaven et al. 2002, Gonzalez-Garcia et al. 2003) indicate that the velocity of the sites with respect to a rigid Pacific plate have significant residuals. These observations suggest that the Peninsula is not completely coupled with the Pacific plate and the Gulf of California spreading does not fully represent the NA/PA motion. Here we suggest using the extensive network of campaign GPS of CICESE/University of Miami combined with the Southern California Earthquake Center (SCEC) for the Mexico/US border region, to quantify the missing motion and how it is accommodate. In particular, we will use the GPS and numerical models to verify if BC behaves as a rigid block as the absence of intra-peninsular faults seems to indicate (in this case the missing motion must be searched west of BC).
DE: 1209 Tectonic deformation (6924)
DE: 8105 Continental margins: divergent (1212, 8124)
DE: 8150 Plate boundary: general (3040)
DE: 8155 Plate motions: general (3040)
DE: 8158 Plate motions: present and recent (3040)
SC: Tectonophysics [T]
MN: Fall Meeting 2005