Utilizing Results from InSAR to Develop Seismic Location Benchmarks and Implications for Seismic Source Studies

Relocation Results

  • Relocated the events using three different global and regional velocity models [IASP91, SSB (Jih, 1998), and TIBET (Jih, 1998)], PPCs when available (the TIBET model does not have calculated PPC surfaces), and a depth fixed at 3 km.
  • To show relative relocation differences between the candidate events, we restricted the stations used in the relocation to those common to both events.
  • Relocations appear to migrate towards the main rupture surface instead of the secondary rupture surface. Suggests both candidate events were, most likely, located on or near the main rupture.
  • The 90% error ellipses for the relocations do not encompass any part of the secondary rupture.
  • The relative distances between the relocated events are consistent with the ~30 km separation indicated by the Rayleigh wave offset. Again suggests that the candidate events are not associated with the secondary rupture.
  • Also relocated the candidate event above that was discarded due to lower than desired SNR at nearby stations.
    Using regional stations only with PPCs, the event relocated from ~110 km to ~30 km from the secondary rupture.
    Only event to relocate in relative proximity to the secondary rupture. When limiting the stations used to those common for the two candidate events above, the event relocated off the view of Figure 5. Relocation instability precludes us from identifying it as the secondary rupture event.

  • Introduction | Surface Rupture | Data and Velocity Models | Synthetic Tests and Relocation Procedure | Search for Secondary Rupture Event | Relocation Results | Waveforms for Candidate Events | Relocation of Candidate Events | Conclusions and Recommendations | References