شبیه سازی زمین لرزه های احتمالی مطابق دینامیک گسستگی
Abstract
1- Introduction
2- Method and model
3- Results
4- Discussion
5- Conclusions
References
Abstract
The XiLuoDu reservoir dam located on the Jinsha River is one of the largest dams in the world. Nearby faults are very active, and two M > 7 strong earthquakes have occurred around the dam. Simulating the rupture dynamics of potential earthquakes on the surrounding faults is very important to estimate the seismic hazard for the dam. In this research, we use the curved grid finite difference method (CG-FDM) to simulate spontaneous ruptures on the major faults around the dam. The main results are that the Leibo middle and south faults (LBMF and LBSF) are more likely to have large destructive earthquakes than the Mabian-Yanjin east fault (MB-YJEF). Asperities on faults that have an impact on strong ground motion are formed under the combined influence of the regional background stress field and fault geometry. Spontaneous ruptures on the LBMF and LBSF are mainly strike-slip with minor thrust components, while those on the MB-YJEF are strike-slip and thrust; these results are consistent with the focal mechanisms of recorded small and moderate earthquakes in this area.
Introduction
The Jinsha River , with a total length of 3364 km, is located in the upper reaches of the Yangtze River in China and is rich in water energy resources. There are four world -class reservoir dams on its lower reaches . The XiLuoDu reservoir is located in the Jinsha River gorge section between Leibo County in Sichuan Province and Yongshan County in Yunnan Province; it has a total reservoir capacity of 13.6 billion m3 and a maximum dam height of 278 m (https://www.ctg.com.cn/sxjt/zt98/cyjsj/xwtqh/313438/index.html). This reservoir is a large -scale project that is useful for power generation, flood control, sediment retention and improvement of downstream shipping conditions, but the reservoir is located within the Daliangshan sub -block at the junction of the Qinghai -Tibetan block and the South China block (Deng et al., 2003; Diao et al., 2014; Zhang et al., 2003 ). The seismicity and earthquake intensity are both very strong in this area. The seismic resistance of the reservoir dam is very important (https://www.ctg.com.cn/sxjt/zt98/cyjsj/xwtqh/313438/index.html), and a more accurate estimation of earthquake disasters in the dam site area is urgently needed. Some faults are active around the dam. The Lianfeng fault (LFF) and many small faults in the Mabian -Yanjin fault zone are mainly distributed within 20 -30 km of the XiLuoDu dam, forming a nearly triangular small block called the Leibo -Yongshan triangular block.