论文部分内容阅读
2015年4月25日尼泊尔发生M w7.8级大地震,震源机制解结果一致表明该地震为低角度逆冲型.迄今发生百余次余震,其中包括M s7.0级以上强余震,并触发正断层型小震群.此次地震发生于喜马拉雅碰撞造山带中段,位于1934年比哈-尼泊尔M w~8.1级和1505年木斯塘M w~8.2级地震之间的地震空区内,是自1950年察隅M w~8.4级地震以来喜马拉雅主逆冲断裂上发生的最大震级地震.为更好地理解这次地震,本文综述喜马拉雅造山带的构造背景、断裂组合构成和几何形态、历史强震分布和破裂范围、现代小地震活动性特征、强震孕育的基本模式、震间加载和同震位移的空间互补性.在简单介绍同震破裂的断面初始解基本特征基础上,初步讨论了这次尼泊尔地震与喜马拉雅带特征型地震的关系,与2008年汶川地震的比较,以及低角度逆冲地震破裂的地表出露和对区域地震危险趋势的指示意义等问题.
The Mw7.8 earthquake occurred in Nepal on April 25, 2015. The results of the focal mechanism solution consistently show that the earthquake is a low-angle thrust type. Hundreds of aftershocks have occurred to date, including strong aftershocks above MS7.0 and Triggering a normal faulting type small swarm.These earthquakes occurred in the middle of the Himalayan collision orogenic belt and were located within the seismic space between Mha 8.1 of Biha-Nepal in 1934 and the Mwu 8.2 Mushtang earthquake in 1505 Is the largest magnitude earthquake on the Himalayan thrust since the Mw5.4 Qaqa earthquake in 1950. To better understand this earthquake, this paper reviews the tectonic setting, fracture composition and geometry of the Himalayan orogenic belt , The distribution and rupture range of historical strong earthquakes, the active characteristics of modern small earthquakes, the basic patterns of strong earthquakes, the spatial complementarity of seismic loading and the coseismic displacements.Based on the brief introduction of the basic characteristics of the initial solution of the coseismic rupture section, The relationship between this Nepal earthquake and the Himalayan characteristic earthquake was discussed tentatively, compared with the Wenchuan earthquake in 2008, and the surface exposure of the low-angle thrust earthquake rupture and its significance to the regional earthquake danger trend problem.