T52A-08
Toward Building a New Seismic Hazard Model for Mainland China
Friday, 18 December 2015: 12:05
304 (Moscone South)
Yufang Rong1, Xiwei Xu2, Guihua Chen1,2, Jia Cheng1,3, Harold Magistrale1 and Zhengkang Shen4, (1)FM Global Research, Norwood, MA, United States, (2)Institute of Geology, China Earthquake Administration, Beijing, China, (3)CEA China Earthquake Administration, China Earthquake Networks Center, Beijing, China, (4)University of California Los Angeles, Dept. of Earth, Planetary, and Space Sciences, Los Angeles, CA, United States
Abstract:
At present, the only publicly available seismic hazard model for mainland China was generated by Global Seismic Hazard Assessment Program in 1999. We are building a new seismic hazard model by integrating historical earthquake catalogs, geological faults, geodetic GPS data, and geology maps. To build the model, we construct an Mw-based homogeneous historical earthquake catalog spanning from 780 B.C. to present, create fault models from active fault data using the methodology recommended by Global Earthquake Model (GEM), and derive a strain rate map based on the most complete GPS measurements and a new strain derivation algorithm. We divide China and the surrounding regions into about 20 large seismic source zones based on seismotectonics. For each zone, we use the tapered Gutenberg-Richter (TGR) relationship to model the seismicity rates. We estimate the TGR a- and b-values from the historical earthquake data, and constrain corner magnitude using the seismic moment rate derived from the strain rate. From the TGR distributions, 10,000 to 100,000 years of synthetic earthquakes are simulated. Then, we distribute small and medium earthquakes according to locations and magnitudes of historical earthquakes. Some large earthquakes are distributed on active faults based on characteristics of the faults, including slip rate, fault length and width, and paleoseismic data, and the rest to the background based on the distributions of historical earthquakes and strain rate. We evaluate available ground motion prediction equations (GMPE) by comparison to observed ground motions. To apply appropriate GMPEs, we divide the region into active and stable tectonics. The seismic hazard will be calculated using the OpenQuake software developed by GEM. To account for site amplifications, we construct a site condition map based on geology maps. The resulting new seismic hazard map can be used for seismic risk analysis and management, and business and land-use planning.
