东昆仑活动带断裂库赛湖段破裂行为及影响因素的初步研究

On November 14, 2001, an extraordinarily large earthquake (MS8.1) occurred on the Hoh Sai Hu segment of the Eastern Kunlun Fault, in the northern Qinghai-Tibetan Plateau. The seismogenic fault, the Hoh Sai Hu segment, is a left-lateral fault with a high slip rate in geological history, with the average slip rate reaching(14.8±2.8)mm/a since the late Pleistocene. Different slip rates of the Hoh Sai Hu segment can affect fault motion in the future. Therefore, this paper analyzes the effect of different slip rates and different initial friction coefficients on the fault plane of the Hoh Sai Hu segment of the eastern Kunlun Fault on the rupture behaviors of the fault. In this research, we apply the single degree of spring block model controlled by the rateand state-dependent frictional constitutive laws. Using the fault dislocation model and based on ancient earthquake research, historical earthquakes data and the achievements of previous researchers, we obtained the parameters of this model. Through numerical simulation of the rupturing motion of the Hoh Sai Hu segment in the next 6500 years under different slip rates, we find that a faster annual slip rate will shorten the recurrence interval of the earthquake. For example, the earthquake recurrence interval is 2100a at a slip rate of 0.014m/a, which agrees with previous research, 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. The fault slip rate has no regular effect on the coseismic slip rate and fault displacement in an earthquake. The initial friction coefficient on the fault surface has an effect on the earthquake recurrence interval. A smaller initial friction coefficient will lengthen the earthquake recurrence interval. At the same time, the smaller initial friction coefficient will lead to larger slip rates and fault displacement when earthquakes occur.

The Preliminary Research on Rupture and Factors Affecting Rupturing of the Hoh Sai Hu Segment in Eastern Kunlunshan