Ground Truth Locations Using Synergy Between Remote Sensing and Seismic Methods

摘要

In this study, we have relocated a set of 50 ground truth (GT) earthquakes as determined from regional modeling, to estimate the performance of the station correction methodology. We constructed station-specific source correction or 'station correction' surface from 760 station correction (global distribution) based on a small set of five well and closely located earthquakes in the central Tibetan Plateau. The station corrections were interpolated to develop a global surface for P-wave travel time corrections. As a test, we relocated a set of 50 GT earthquakes, with some seismic events located about 800 km from the center of the PASSCAL array across the Tibetan Plateau and surrounding regions. When the corrections were applied to the iasp91 velocity model, the mislocations decreased by an average by 37% for 37 out of the 50 GT events. This indicates significant improvement in seismic event locations relative to using the iasp91 model without P-wave travel-time corrections. Surprisingly, the distribution of mislocations did not vary or correlate with distance and some of the farthest events from the center of the Tibetan Plateau were improved more than the locations in the center where the travel time corrections are more relevant. Myers and Schultz (2000) noted that correction surfaces for nearby stations are similar, suggesting coherent assessment of the results, corrections could be developed from a small cluster of earthquakes and transported for use with seismic events outside of the area out to a radius of 800 km. Additional tests should be performed to further validate these claims especially when crossing tectonic boundaries.