Abstract: Most earthquakes result from fault activity under heterogeneous loading and complex physical properties, also affected by fault structure and interaction between faults. Such a complicated mechanism makes often failures of the "seismic gap" theory in the effort of medium-and long-term earthquake prediction. This study attempts to address this issue using the finite element method(FEM).The friction behavior of faults can be used to simulate the non-uniformity of rupture processes of the seismogenic structure. So we use the FEM containing non-linear friction to simulate fault ruptures in the Daliangshan sub-block and adjacent areas, and compare the results with time-space evolution of historical M_S ≥ 7 earthquakes since 1840 in this region. In the simulation, the sequence of large-batch fault contact nodes change from "stick state" to "slip state" in short time, which mimics the sudden fault slip and the occurrence of major earthquakes. The results show that the fault breaking lengths from simulation are largely consistent with the magnitudes of historical earthquakes in the study area, such as the 1850 Puge-Xichang M_S7.5, and 1887 Shiping M_S7.0 earthquakes. The simulation also shows the development of seismic gaps and "gap breaks" by major earthquakes on the Xianshuihe fault, such as 1955 Kangding M_S7.5 earthquake. Especially, the results illustrated the very long time of the seismogenic process of the 2008 Wenchuan M_S8.0 earthquake, and the corresponding sudden big rupture along the Longmenshan Fault, which is very similar to the observed surface rupture and very long incubation time and sudden co-seismic process. Then, this simulation is further applied to long-term earthquake prediction for the study area by calculation on a much longer time. The simulation results suggest that the Xiaojiang fault and the Zemuhe fault have relatively higher seismic risk, while moderate-sized earthquakes might occur on the Daliangshan fault and the Aninghe fault, and major earthquakes might rupture the northern segment of the Xianshuihe fault in a much longer time.

Key words: Non-linear friction, seismic risk, Daliangshan, Historical earthquake

摘要： 大部分地震是在复杂的物性条件下，应力不均匀加载作用下断层活动的结果，还受到断层结构和断层相互作用的影响，导致地震中长期预测研究中常用的"地震空区"理论出现误差。断层的摩擦行为可以体现断层的不均匀破裂过程，文中尝试将非线性摩擦有限元方法应用到区域地震危险性评价中，模拟计算了大凉山次级块体及周边地区主要断层的摩擦行为，将断层节点破裂与7级以上历史地震的时空演化进行对比。结果表明，模拟所得的断层破裂与历史地震对应较好，且在地震震级、地震破裂顺序上都有良好表现。模拟结果还显示，小江断裂和则木河断裂有可能是后续地震危险性较强的地区，在更长的时间内，大凉山断裂和安宁河断裂具有发生中等强度地震的可能，鲜水河断裂的北段可能发生较大地震。

关键词: 非线性摩擦, 地震危险性, 大凉山, 历史地震