[1]SU Shan,HAN Libo,GUO Xiangyun.Study on Focal Mechanism and Stress Field Before and After the Impoundment in the Vicinity of the Xiluodu Reservoir[J].Journal of Seismological Research,2020,43(02):402-411.
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Study on Focal Mechanism and Stress Field Before and After the Impoundment in the Vicinity of the Xiluodu Reservoir
Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
43
Number of periods:
2020 02
Page number:
402-411
Column:
Public date:
2020-06-10
- Title:
- Study on Focal Mechanism and Stress Field Before and After the Impoundment in the Vicinity of the Xiluodu Reservoir
- Keywords:
- Xiluodu Reservoir; focal mechanism solutions; stress field; HASH method; Spatial and temporal stress inversion(SATSI)
- CLC:
- P315.72
- DOI:
- -
- Abstract:
- The impoundment of water reservoirs may induce significant seismicity and increase regional seismic hazard,thus has attracted more attention in recent years. Here we focused on the Xiluodu Reservoir,one of the biggest hydropower stations worldwide. We collected digital waveform data during 01/2009 ～ 01/2018 recorded by regional seismic network from the Data Management Centre of China National Seismic Network at Institute of Geophysics,China Earthquake Administration. We first adopted the HASH method to determine the focal mechanism solutions of ML≥2.0 seismic events using their P wave first-motion polarities and S/P amplitude-ratios. Comparisons between different methods or agencies confirmed these solutions were well constrained. Then the source mechanism solutions with high quality were inverted to obtain the local stress field utilizing the spatial and temporal stress inversion(SATSI)method. The effect of reservoir impoundment on the changes in local stress was assessed by analyzing these focal mechanism solutions and the spatio-temporal distribution of the stress field. Most of earthquakes showed oblique focal mechanisms prior to the impoundment of reservoir while were dominated by the thrust or strike-slip focal mechanisms after that. In addition,the inversion of local stress field revealed relatively significant change in the plunge angle of the minimum stress axis after the impoundment. We suggest that the stress changes due to the impoundment of reservoir may have affected the stress state in the crust and therefore provide some constraints on the local stress field.
- References:
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Last Update:
2020-06-10