2015年尼泊尔M_S8.1强震对中国大陆静态应力触发影响的初探

本研究基于地震危险性分析中地震重复原则和构造外推原则,以及一段时期内活动断裂上发生地震机制是相似或相近的假设,利用中国已发生的震级为MS5.0以上的地震震源机制解,将其中的一个节面视为实际地质断层参数和静态应力触发计算中的接收断层面,计算了2015年4月25日尼泊尔MS8.1地震对中国大陆地区的静态应力触发情况.研究结果表明:2015年4月25日尼泊尔MS8.1地震,触发了其后续的2次强余震的发生;本次地震对中国大陆产生的应力变化量值很小,其产生的应力加载主要集中在其邻近的西藏和新疆地区的部分断层上,而其余地区的断层则主要受到了应力卸载作用.

Preliminary study on the static stress triggering effects on China mainland with the 2015 Nepal MS8.1 earthquake

This study was based on the principles of earthquake recurrence and the structural extrapolation in seismic risk analysis, and the hypothesis that earthquakes occurring on an active fault would have similar or close focal mechanisms within a period of time. Based on the line of thought, we used the earthquake focal mechanism solutions of events greater than M_S 5.0 in China to calculate the static stress triggering by the M_S8.1 Nepal earthquake of 25 April 2015. In this analysis, one of the nodal plane of the focal mechanism solution was regarded as the actual geological fault parameter and the receive fault plane in the static stress triggering calculation. The results show that the two subsequent strong aftershocks in Nepal were triggered by the M_S8.1 Nepal shock. There was little change in the magnitude of stress generated by the main shock. The stress loading generated by the main shock was concentrated on some faults in Tibet and Xinjiang neighboring Nepal. While the faults in other regions suffered from stress unloading.