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,...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.展开更多
In this study, the North China seismic region was selected as the study area, and evaluation of seismic hazard using the spatial smoothing seismicity model was performed. Firstly, the study area is divided into grids,...In this study, the North China seismic region was selected as the study area, and evaluation of seismic hazard using the spatial smoothing seismicity model was performed. Firstly, the study area is divided into grids, and some parameters （e. g. b-value, Mo, Me, azimuth and M-L relationship ） for each seismotectonic model were assigned. Secondly, using elliptical smoothing based on a seismotectonic background model, the statistical earthquake incidence rate in each grid is successively calculated. Lastly, the relevant ground motion attenuation relationship is chosen to assess seismic hazard of general sites. The maps for the distribution of horizontal peak ground acceleration with 10% probability of exceedance in 50 years were obtained by using the seismic hazard analysis method based on grid source. This seismicity model simplifies the methodology of probabilistic seismic hazard analysis, especially appropriate for those places where seismic tectonics is not yet clearly known. This method can provide valuable references for seismic zonation and seismic safety assessment for significant engineering projects.展开更多
基金jointly sponsored by the Special Program of Basic R&D Fund,Institute of Geology,CEAthe Seismic Industry Research Program,CEA( 200808018)
文摘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.
基金funded by the Special Fund for Fundamental Research of Central-level Public Interest Institutions,China(ZDJ2011-13)
文摘In this study, the North China seismic region was selected as the study area, and evaluation of seismic hazard using the spatial smoothing seismicity model was performed. Firstly, the study area is divided into grids, and some parameters （e. g. b-value, Mo, Me, azimuth and M-L relationship ） for each seismotectonic model were assigned. Secondly, using elliptical smoothing based on a seismotectonic background model, the statistical earthquake incidence rate in each grid is successively calculated. Lastly, the relevant ground motion attenuation relationship is chosen to assess seismic hazard of general sites. The maps for the distribution of horizontal peak ground acceleration with 10% probability of exceedance in 50 years were obtained by using the seismic hazard analysis method based on grid source. This seismicity model simplifies the methodology of probabilistic seismic hazard analysis, especially appropriate for those places where seismic tectonics is not yet clearly known. This method can provide valuable references for seismic zonation and seismic safety assessment for significant engineering projects.
