The Effect of Secondary Arrivals on Regional Earthquake Locations


Summary

Conclusions and Future Work
  1. A significant percentage of events listed in major catalogs have S phases available for location, but are seldom used.
  2. Synthetic tests demonstrate that we have adequate azimuthal coverage to locate events if the velocity model is constrained.
  3. With Gaussian noise added to synthetic detection, the locations scatter with an average mislocation of 8.1 km.
  4. Regional weighting of arrivals improves mislocations.
  5. The inclusion of LANL regional arrival picks help stabilize the main Tibet shock.
  6. Including S phases without PPCs biases the locations.
  7. Using PPCs with teleseimsic data for small events gives us better clustering, and events follow the surface rupture.
  8. The development of a regional S-wave velocity models should improve locations.
  9. PPCs for S phases should be calculated for Asia.

 

References

Bratt, S. R., and T. C. Bache (1988). Locating events with a sparse network of regional arrays, Bull. Seismo. Soc. Am. 78, 780-798.

Jih, R.-S. (1998). Location calibration efforts in China, in Proceedings of the 20th Annual Seismic Research Symposium, 12 pp.

Nagy, W. (1996). New region-dependent travel-time handling facilities at the IDC: Functionality, testing, and implementation details, SAIC Tech Rep. 96/1179, 57 pp.

Steck, L. K., A. A. Velasco, A. H. Cogbill, and H. J. Patton (2000). Improving regional seismic event location in China, Pure & Appl. Geophys., in press.

Velasco, A. A., C. J. Ammon, and S. L. Beck (2000). Broadband source modeling of the November 8, 1997 Tibet (Mw = 7.5) earthquake and its tectonic implications, J. Geophys. Res., in press.


Introduction | Catalog Locations with Secondary Phases | Ground Truth Constraints on Relocations Near a Large-Magnitude Event
Synthetic Tests Pt. 1 | Synthetic Tests Pt. 2 | Relocations of Actual Data | Relocations Using S Phases for the Asia Study Area | Summary