A tectonic stress map of China and adjacent regions from earthquakes occurred during 2000∼2004

Abstract

Earthquake focal mechanism solutions provide the basic information about the present-day regional tectonics stress distribution, which controls the activities of crustal faults. Therefore, continued efforts for updating the database of earthquake focal mechanism solutions are quite valuable and important. The international lithosphere program initiated the ′′world stress map project′′ (Zoback, 1992) since 1980′s. During this project, worldwide studies and measurements of present-day regional tectonics stresses had been put together to establish the database of the global tectonics stresses, and to produce the ′′world stress map′′, which also included information about the present-day regional tectonics stresses of the East Asia. Based on the 1992 version of the world stress map, XU Zhong-huai (2001) had made several improvements, including earthquake centroid moment tensor (CMT) solutions of 2 993 shallow events, focal mechanism solutions according to the P-wave first motions of 404 earthquakes, and 47 bore-hole breakout measurements, and had produced the maps of the present-day regional tectonics stresses, and earthquake focal mechanism solutions of the east Asia. In this study we have tabulated all the available earthquake CMT solutions within China and adjacent regions from the Harvard University catalog for the 5-year period starting on January 1, 2000. Following Xu′s (2001) approach we have derived the maps of hypocenter distribution and earthquake focal mechanism solutions within China and adjacent regions for 2000~2004. Based on the analyses of these data we have discussed the seismic activity and the distribution of earthquakes within different tectonic regions and at different depths. This study has extended the database presented in XU (2001) for another 5 years to 2004.