4:45 PM - 5:00 PM
[S10-1-02] Using GNSS data to analysis the earthquake potential of Sichuan-Yunnan region, western China
We used GNSS data to estimate the seismic hazard potential in the Sichuan-Yunnan region, western China by two approaches.
The first approach, based on the assumption that the earthquake probability is proportional to crustal strain rate, is to use secular geodetic strain rate deduced from GPS velocity data to constrain the probability model. Retrospective test of the model with earthquake occurrence of the past 30 years shows that the model ‘forecasted' poorly. However, the model seems to ‘forecast' spatial intensity of earthquakes for the past 500 years reasonably well, suggesting that the geodetic strain rate obtained at the decadal scale may still be a good indicator of long term earthquake activity in the region, but only at a time scale of hundreds of years.
The second approach is to use GPS velocity data to determine the seismic moment accumulation rates on major faults, and use a historical earthquake catalog to estimate seismic moments released in the past. Comparison of the two yields estimates of present day seismic moments accumulated on major faults, and a retrospective test shows some predictive power of the method.
Our result shows that numerous faults in the Sichuan-Yunnan region have accumulated seismic moments capable of producing M > 7.5 earthquakes, which are the Xiaojiang, Jiali, Northern Nujiang, Nandinghe, Red River-Puer faults, and the junction fault between the Xianshuihe and Ganzi-Yushu faults.
The first approach, based on the assumption that the earthquake probability is proportional to crustal strain rate, is to use secular geodetic strain rate deduced from GPS velocity data to constrain the probability model. Retrospective test of the model with earthquake occurrence of the past 30 years shows that the model ‘forecasted' poorly. However, the model seems to ‘forecast' spatial intensity of earthquakes for the past 500 years reasonably well, suggesting that the geodetic strain rate obtained at the decadal scale may still be a good indicator of long term earthquake activity in the region, but only at a time scale of hundreds of years.
The second approach is to use GPS velocity data to determine the seismic moment accumulation rates on major faults, and use a historical earthquake catalog to estimate seismic moments released in the past. Comparison of the two yields estimates of present day seismic moments accumulated on major faults, and a retrospective test shows some predictive power of the method.
Our result shows that numerous faults in the Sichuan-Yunnan region have accumulated seismic moments capable of producing M > 7.5 earthquakes, which are the Xiaojiang, Jiali, Northern Nujiang, Nandinghe, Red River-Puer faults, and the junction fault between the Xianshuihe and Ganzi-Yushu faults.