Quality Evaluation and Seismotectonic Application of BATS Centroid Moment Tensor Catalogue for Regional Earthquakes around Taiwan
Date Issued
2008
Date
2008
Author(s)
Liao, Che-Wei
Abstract
This study collected 1130 regional centroid moment tensor (CMT) solutions, which were obtained by the Institute of Earth Sciences, Academia Sinica for earthquakes occurred in the Taiwan region in 1995-2005 by inverting the BATS broadband waveforms, to characterize their statistic properties and tectonic implications. The moment magnitude ranges from 3.3 to 7.1 in this catalog with a complete magnitude (Mc) of ~4.0 and the b-value of 0.921. Predominant thrusting events(42.92％) are common in the colliding boundary, fold-and-thrusting belt, and subducting interface, whereas the normal faulting(4.51％) presents mainly in the Okinawa Trough, northern Hoping Basin, and the eastern Central Range.o evaluate the robustness of BATS CMT solutions, this study compares 96 CMT solutions in common between BATS and GCMT catalogs. Results show that the BATS solutions are well constrained for events with misfit < 0.5, which are roughly comparable to solutions of GCMT with moment error < 0.2. The BATS Mw is generally less than GCMT Mw by an average of ~0.17. This is very likely due to the insufficient quality of solutions in GCMT catalog for small earthquakes. For obtaining more robust solutions in the future, the uncertain of epicenter location, velocity model and station coverage must be improved by new techniques such like location searching, 3-D Green’s function.orizontal seismic strain directions, which are shown in terms of well constrained BATS CMT dataset, agree well with the surface geodetic GPS observations. Seismic strain rate along the Costal Range is ~1E-7/yr, which is about one order of magnitude smaller than the one derived from GPS measurements. This study applies Michael’s method (1984) to invert the stress tensor for obtaining the seismic stress field in the Taiwan region. Finally, we take advantage of these results to delineate the seismogenic structures associated with tectonic processes around Taiwan. Our results provide seismological constraints on the mode of deformation and stress field in the Taiwan region.
Subjects
BATS
CMT
Quality
Application
Stress
Strain
Taiwan
Type
thesis
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