[J03-2] Deformation of the lithosphere: Integrating seismology and geodesy through modelling II

[J03-2-05] Crustal deformation and surface kinematics after the 2010 earthquakes in Latin America

^○Laura Sanchez, Hermann Drewes (Deutsches Geodaetisches Forschungsinstitut, Technische Universitaet Muenchen, Germany)

A continuous crustal deformation model for Latin America and the Caribbean inferred from GNSS measurements gained after the strong earthquakes occurred in 2010 in Chile and Mexico is presented. This model is based on a multi-year velocity solution for a network of 456 continuously operating GNSS stations covering a five years period. The deformation model is computed from the discrete station velocities using the least square collocation (LSC) approach with empirically determined covariance functions. While the effects of the Baja California earthquake can be considered as local, the effects of the Maule earthquake changed the surface kinematics of a large area (between the latitudes 30S-45S from the Pacific to the Atlantic coasts). Before the Maule earthquake, the strain rate field in this area showed a strong west-east compression with maximum rates of about 0.40 micro-strain/a. In accordance, the deformation vectors were roughly parallel to the plate subduction direction and their magnitudes decreased with the distance from the subduction front. After the earthquake, the largest compression (0.25 micro-strain/a) occurs between the latitudes 37S and 40S with a N30E direction. The maximum extensional strain rate (0.20 to 0.35 micro-strain/a) is observed in the Sub-Andean zone in the Patagonia south of latitude 40S. The extensional axes rotate from a N30E direction in the central Araucania zone to a westerly direction of N72W in the western part of Patagonia. In the northern region of parallel 35S, the extension is also directed to the Maule zone (S45W) but with quite small rates. This complex kinematics causes a large counter clockwise deformation pattern rotating around a point south of the epicentre (35.9S, 72.7W). The magnitude of the deformation vectors varies from 1 mm/a close to the rotation point up to 22 mm/a near the 2010 earthquake epicentre. The direction of the largest deformation vectors points to the epicentre.