HR: 10:35h
AN: G42A-02 INVITED     [Abstracts]
TI: Surface deformation during the subduction zone earthquake cycle in southern Peru and northern Chile
AU: * Pritchard, M E
EM: mp337@cornell.edu
AF: Department of Earth & Atmospheric Science, Cornell University, Snee Hall, Ithaca, NY 14853, United States
AU: Loveless, J P
EM: jpl34@cornell.edu
AF: Department of Earth & Atmospheric Science, Cornell University, Snee Hall, Ithaca, NY 14853, United States
AU: Finnegan, N J
EM: njf7@cornell.edu
AF: Department of Earth & Atmospheric Science, Cornell University, Snee Hall, Ithaca, NY 14853, United States
AU: Norabuena, E O
EM: enorab@nazca.igp.gob.pe
AF: Departamento de Geodesia y Sismotectonica, Instituto Geofisico del Peru, Calle Badajoz 169, Urb. Mayorazgo-4Etapa, Lima, Peru
AU: Simons, M
EM: simons@caltech.edu
AF: Seismological Laboratory, Division of Geological and Planetary Sciences, California Institute of Technology, MC 252-21, Pasadena, CA 91125, United States
AB: We use InSAR, GPS, teleseismic, and strong motion data to constrain the location of inter-seismic, co-seismic, and post-seismic fault slip on the shallow megathrust in the southern Peru and northern Chile subduction zone during the last 20 years. For six of the earthquakes studied (6.7 < Mw < 8.4), we invert seismic and geodetic data both jointly and separately to determine the rupture processes (co-seismic deformation). In northern Chile, because of the spatially and temporally dense geodetic data, we can clearly separate co-seismic and post-seismic deformation. We document a complex mosaic of phenomena including large earthquakes, post-seismic after-slip with a spatial distribution that appears to be related to variations in coastal morphology, and a completely aseismic pulse that may have triggered a Mw 7.1 earthquake in 1998. In contrast to simple models of fault slip behavior, this spatial heterogeneity indicates that frictional parameters on the fault do not have a systematic transition with depth and also vary rapidly along-strike. Finally, we discuss our ability to measure inter-seismic deformation given the various sources of noise in the InSAR data, including: changes in the water vapor content of the troposphere, perturbations in the ionosphere, and uncertainty in the precise orbital positions of the satellites.
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