Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published August 19, 2006 | Published
Journal Article Open

An aseismic slip pulse in northern Chile and along-strike variations in seismogenic behavior


We use interferometric synthetic aperture radar, GPS, and seismic observations spanning 5 to 18 years to reveal a detailed kinematic picture of the spatiotemporal evolution of fault slip in a region corresponding to the 30 July 1995 M_w 8.1 subduction zone megathrust earthquake in northern Chile. In a single area, we document a complex mosaic of phenomena including large earthquakes, postseismic afterslip with a spatial distribution that appears to be tied to variations in coastal morphology, and a completely aseismic pulse that may have triggered a M_w 7.1 earthquake on 30 January 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. The low amount of afterslip from the M_w 8.1 earthquake relative to other similar events suggests that postseismic behavior may be modulated by the amount of sediment subducted.

Additional Information

© 2006 American Geophysical Union. Received 2 January 2006; revised 6 April 2006; accepted 12 May 2006; published 19 August 2006. ERS SAR imagery for this study was acquired as a category 1 research project from the European Space Agency. We thank R. Bürgmann, T. Baba, and Associate Editor S. Cohen for critical reviews, as well as M. Chlieh, H. Kanamori, J. Klotz, T. Heaton, and M. Gurnis for discussions. GMT was used to create several figures [Wessel and Smith, 1998]. M.E.P. was partly supported by a Hess postdoctoral fellowship at Princeton University. This is Caltech Tectonics Observatory contribution 41 and Caltech Seismological Laboratory contribution 9151.

Attached Files

Published - pritchard_simonsJGR2006.pdf


Files (6.0 MB)
Name Size Download all
6.0 MB Preview Download

Additional details

August 22, 2023
October 20, 2023