Source Studies

Figure 1(below): Kinematic source model of the 05/21/2003 earthquake Based on the method defined by Vallee and Bouchon (2003), we describe the rupture as a collection of slip patches. In this case, 2 patches are enough to insure a good fit to teleseismic P waves (see figure 2). The chosen focal mechanism is the Harvard-inferred mechanism, and the hypocentral depth is fixed at 10km. The hypocenter is denoted by a star. We obtain a well-resolved shallow asperity which could be responsible of the worst damage linked to this earthquake. The global duration of the earthquake is about 17s.

Figure 1

Figure 2: Fit to teleseismic P waves We present here the fit obtained at 11 eleven stations of the IRIS network. We have modelled here the 20 first seconds of the Pwave displacements. Blue curves are the data and red curves the synthetics corresponding to the kinematic model of figure 1. Azimuth and name of each station are specified in each subfigure. A more precise model will be defined later by the addition of SH waves and surface waves.

Figure 2

Figure 3: Geographical projection of the coseismic slip Map view of the kinematic model presented in figure 1.

Figure 3

Vallee, M. and M. Bouchon, Imaging coseismic rupture in far field by slip patches, accepted with minor revison in Geophys. J. Int., 2003.