A comparison between short term (co-seismic) and long term (one year) slip for the Landers earthquake: Measurements from strong motion and SAR interferometry

The long term relative displacements in the region of the Landers earthquake were measured over a time interval of about one year using SAR interferometry. We have also evaluated the co-seismic slip distribution through a strong motion inversion [Cotton and Campillo, 1995] and these results are used to compute the static displacement field associated with the coseismic slip. We show that the synthetic static and the interferometry measurements are in very good agreement. To give an evaluation of the magnitude of the pre- and post-seismic slip, a residual interferogram between data and synthetic co-seismic slip has been computed. A simple analysis of the residual displacements gives a limiting value of the amplitude of pre- and post-seismic slip integrated over a period of one year and suggests that it is on the order of a few decimeters.