Regional characterization of Western China

Abstract

Geological, geophysical, and seismic data are being assembled and organized into a knowledge base for Western China as part of the CTBT Research and Development regional characterization effort. We have begun our analysis using data from the station WMQ of the Chinese Digital Seismic Network (CDSN). Regional seismograms are being analyzed to construct travel time curves, velocity models, attenuation characteristics, and to quantify regional propagation effects such as phase blockages. Using locations from the USGS Preliminary Determination of Epicenters (PDE) we have identified Pn, Pg, Sn, and Lg phases, constructed travel time curves, and estimated apparent velocities using linear regression. Surface wave group velocities will be measured and inverted for regional structure. Preliminary noise spectra for WMQ have been obtained from the IRIS DMC. Chinese seismicity catalogs from the USGS and SSB are being used to identify and obtain seismic data (including mine seismicity) and information for lower magnitude events. We have identified the locations of nearly 500 mines in China for inclusion in the knowledge base. Future work will involve expanding the data collection and analysis efforts to a larger region using data from additional CDSN, IRIS and portable stations