关键词: 断裂, 弹簧滑块模型, 破裂行为, 地震复发周期

Abstract: On 14 November 2001,an extraordinarily large earthquake(M_S 8.1)occurred on the Hoh Sai Hu segment of the eastern Kunlun Fault,northern Tibetan Plateau. The seismogenic fault,Hoh Sai Hu segment,is a left-lateral fault with a high slip rate in the geological history,and the average slip rate reaches(14.8±2.8)mm/a since the late Pleistocene. Different slip rates of Hoh Sai Hu segment can affect the fault motion in the future. So,the paper analyzes the effect of different slip rates and different initial friction coefficients on the fault surface of the Hoh Sai Hu segment of eastern Kunlun Fault on the rupture behaviors of the fault. In the research,we apply the single degree of spring block model controlled by the rate- and state-dependent frictional constitutive laws. Using the fault dislocation model and based on ancient earthquake researches,historical earthquakes data and the achievements of previous researchers,we obtained the parameters of the model. Through the numerical simulation of rupturing motion of the Hoh Sai Hu segment in the future 6500 years under different slip rates,we find that a faster annual slip rate will shorten the recurrence interval of earthquake. For example,the earthquake recurrence interval is 2100a at a slip rate of 0.014m/a,which agrees with previous research results,but,the recurrence interval will be 1000～1500a and 2100～2500a,corresponding to the slip rates of 0.018m/a and 0.008m/a,respectively. Slip rate of fault has no regular effect on the coseismic slip rate and displacement of fault in an earthquake. The initial friction coefficient on the fault surface has effect on earthquake recurrence interval. A smaller initial friction coefficient will lengthen earthquake recurrence interval. At the same time,the smaller initial friction coefficient will lead to larger slip rate and displacement of fault when earthquake occurs.

Key words: fault, spring-block model, rupture behavior, earthquake recurrence interval