**4.4** *sPmP* **modeling for two aftershocks of the** *M***W 6.5 2003/12/22 California earthquake**

Many regional records are available for the main shock and its aftershocks. We retrieved the records of some aftershocks at stations within 5º from IRIS for analysis. We found that two aftershocks have clear *sPmP* phase records at stations VCS (2.76º), CHF (2.89º), PAS (2.87º), and MWC (2.92º). We modeled the *sPmP* and *PmP* at station PAS, and obtained focal depths 6.5 km for the 05:30 event and 6 km for the 18:17 event (Fig. 17). The preliminary focal depths obtained by the local network for the two aftershocks are 5.9 km and 6.9 km, respectively.

Fig. 17. *sPmP* and *PmP* modeling for two aftershocks of the 2003/12/22 Central California *M*W 6.5 earthquake. Trace PAS/BHZ/03Dec23 18:15:08.6 is the record of the aftershock 2003/12/23/ 18:17:11.0 *M* 4.9 at station PAS. Trace PAS/BHZ/03Dec23 05:27:41.0 is the record of the aftershock 2003/12/23/ 05:30:19.0 *M* 4.5. Traces 060 and 065 are the synthetic waveforms generated with depths 6 and 6.5 km at the same station (320 km). The focal depth solution for the 18:17 event is 6 km and for the 05:30 event is 6.5 km.
