Figure 1(a) Four types of source representations arrayed near the end of the magnitude range of their applicability. We have developed the methodology for recovering FMT representations of earthquakes in the magnitude range 4-6 from regional broadband waveform data. The number of FMT parameters varies from 14 to 20, depending on the constraints on the source model.


Figure 1(b) The inverted FMT parameters for the 09/03/2002 M4.8 Yorba Linda earthquake. (Left) the map view: arrow shows the orientation of the fault plane and directivity. (Right) The characteristic dimensions of the rupture; arrow shows the orientation of directivity.


Figure 1(c) Projection of a 3D rendering of the Yorba Linda mainshock (blue sphere) and its aftershocks (gold sphere) relative to the Whittier fault (white triangulated surfaces). Our FMT determined fault plane is consistent with the aftershock distribution. The relocated hypocenters were provided by E. Hauksson, the CFM-A model was provided by A. Plesch and the 3D rendering using the LA3D visualization system was developed by SCEC/Information Technology Research (ITR) interns.