Centroid Moment Tensor Solutions for Taiwan Earthquakes of the WWSSN Era (1963-1975)
Po-Fei Chen1*, Goran Ekstrom2, and Emile Okail1
ABSTRACT
We use analog seismograms to invert seventeen new centroid moment tensor solutions for shallow earthquakes in the vicinity of Taiwan during the period 1963-1975, with the exact same algorithm used to produce the Harvard catalog for modern events recorded on digital seismographs. The average rate of moment release featured by the 17 events is double that of the modern seismicity of the study area, as expressed in the Harvard catalog, and if the 1999 Chi-Chi earthquake and its aftershocks are discarded. Significant deviations in geometryare found between some of our solutions and focal mechanisms previously obstained for the same events by a variety of authors. Our study provides a more complete dataset of focal solutions in Taiwan for future analysis of the regional tectonic strain release.
(key words: Harvard CMT catalog, Taiwan earthquakes, WWSSN)
1. Department
of GEological Sciences, Northwestern University, Evanstion, IL 60201, USA
2. Department of Earth and Planetary Sciences, Harvard University, Cambridge,
MA 02138, USA
* Corresponding author address: Dr. Po-Fei
Chen, National Centeral University, Taiwan
Phone: 886-3-422-7151 ext.65647
E-mail: bob@geps.gep.ncu.edu.tw