Using GPS observation data for the middle segment of the Fenwei seismic zone during the time period of 1996 ～ 2001, the velocity field of crustal movement is calculated. Thus, the vectors of relative horizontal movem...Using GPS observation data for the middle segment of the Fenwei seismic zone during the time period of 1996 ～ 2001, the velocity field of crustal movement is calculated. Thus, the vectors of relative horizontal movement between measuring points in the region are also obtained. Adopting a deformation model of homogeneous elastic body, the principal strain rate parameters of deformation units are calculated. A method is introduced to calculate the rate of seismic moment accumulation due to crustal deformation. The problems of using this rate to analyze the tendency of seismicity in the zone, and to estimate the recurrence interval of large earthquakes in the potential seismic source areas（PSSA） are discussed. The results show that the rate of seismic moment accumulation in the middle segment of the Fenwei zone is 4.22 x 1017 Nm/a, which is much higher than the average release rate of seismic moment in the current activity period. This means that the belt is now in a stage of seismic strain accumulation and that the seismicity would become stronger in the future than now. The results of estimation of the recurrence interval of large earthquakes in the Dingxiang and Huozhou PSSA are close to the results obtained from studying active faults. This implies that the use of the proposed estimation method is worthy of further investigation. In particular, it is of greater practical significance for those regions that have shorter history of earthquake records or lower degree of active structure study.展开更多
With the central part of Shanxi Province as an example, this paper studied seismic intensity zonation directly by use of the response intensity of historical earthquakes. From the result, some conclusions can be drawn...With the central part of Shanxi Province as an example, this paper studied seismic intensity zonation directly by use of the response intensity of historical earthquakes. From the result, some conclusions can be drawn as follows: ① For areas rich in data of historical earthquakes, the seismic intensity zonation map with probabilistic meanings can be compiled by use of the statistical features of the response intensity of sites; ② When determining the length of time for statistics, the completeness of response intensity data and the inhomogeneity of regional seismic activities should be fully considered; ③ By comparing the seismic intensity zonation result for recurrence interval of 500 years with the new Seismic Intensity Zonation Map of China (1990), it has been found that the two are roughly similar; though they are somewhat different for some localities, each has its own reasonableness.展开更多
文摘Using GPS observation data for the middle segment of the Fenwei seismic zone during the time period of 1996 ～ 2001, the velocity field of crustal movement is calculated. Thus, the vectors of relative horizontal movement between measuring points in the region are also obtained. Adopting a deformation model of homogeneous elastic body, the principal strain rate parameters of deformation units are calculated. A method is introduced to calculate the rate of seismic moment accumulation due to crustal deformation. The problems of using this rate to analyze the tendency of seismicity in the zone, and to estimate the recurrence interval of large earthquakes in the potential seismic source areas（PSSA） are discussed. The results show that the rate of seismic moment accumulation in the middle segment of the Fenwei zone is 4.22 x 1017 Nm/a, which is much higher than the average release rate of seismic moment in the current activity period. This means that the belt is now in a stage of seismic strain accumulation and that the seismicity would become stronger in the future than now. The results of estimation of the recurrence interval of large earthquakes in the Dingxiang and Huozhou PSSA are close to the results obtained from studying active faults. This implies that the use of the proposed estimation method is worthy of further investigation. In particular, it is of greater practical significance for those regions that have shorter history of earthquake records or lower degree of active structure study.
文摘With the central part of Shanxi Province as an example, this paper studied seismic intensity zonation directly by use of the response intensity of historical earthquakes. From the result, some conclusions can be drawn as follows: ① For areas rich in data of historical earthquakes, the seismic intensity zonation map with probabilistic meanings can be compiled by use of the statistical features of the response intensity of sites; ② When determining the length of time for statistics, the completeness of response intensity data and the inhomogeneity of regional seismic activities should be fully considered; ③ By comparing the seismic intensity zonation result for recurrence interval of 500 years with the new Seismic Intensity Zonation Map of China (1990), it has been found that the two are roughly similar; though they are somewhat different for some localities, each has its own reasonableness.
