鲜水河断裂带北西段大地震破裂模式及断裂行为研究

认识大地震破裂模式和断裂行为对于评估断裂带发震能力和地震危险性有重要意义。滑动速率相对较高的鲜水河断裂带是位于青藏高原东缘的大型左旋走滑断裂带，是川藏铁路穿过的活动性最强的断裂之一。本申请以几何结构相对简单，但兼具大地震同震破裂、无震滑移（蠕滑）及中小地震等多重滑动行为的鲜水河断裂带北西段为研究对象，一方面，结合卫星影像解译、无人机摄影测量、野外调查等方法刻画断裂带精细的几何结构，获取1973年炉霍7.6级大地震等现今地震的详实的地表破裂展布形态和同震位移分布规律；另一方面，通过寻找最佳古地震研究点位开挖探槽，尽可能准确、完整的限定古地震序列。利用地质学方法，研究大地震时空分布、破裂特征和重复行为及其与蠕滑段和断层摩擦行为的关系；进一步综合古地震、历史地震、现今大地测量等资料，分析断裂带发震能力和地震危险性。

It is significant to understand the rupture characteristics and faulting behavior in order to evaluate the seismogenic capacity and seismic hazard. The Xianshuihe fault zone with a high slip rate is a large left-lateral active fault located at the eastern margin of the Tibet Plateau, and it is one of the most active faults along the Sichuan-Tibet railway. The fund application focuses on the northwest section of the Xianshuihe fault zone, which has a relatively simple geometric structure, however, has multiple slip behaviors such as great earthquake coseismic rupture, aseismic slip, and small-moderate earthquakes. On the one hand, combining with satellite image interpretation, UAV photogrammetry, and field geological investigation, the detailed geometry structure of the fault will be described, and the distribution of surface rupture and coseismic displacement of the great historical earthquakes, such as the 1973 Luhuo 7.6 earthquake, will be obtained. On the other hand, by searching for the best paleoseismic research site to excavate the trenches, the accurate and complete sequences of paleoearthquake may be defined. Using geological methods, the relationship between the spatial and temporal distribution, the rupture and recurrence characteristics of great earthquakes and the friction behavior along the present creep and stick sections of the fault will be studied. And the data of paleoearthquakes, historical earthquakes and present geodesy are further integrated to contribute to the analysis of seismic capacity and seismic hazard of the northwestern section of the Xianshuihe fault zone.