与特征断层结合的地震活动空间光滑模型在衡水市活断层地震危险性评价中的应用

The application of spatially smoothed seismicity model combined with the characteristics of the faults in Hengshui seismic risk evaluation

在衡水市活断层地震危险性评价中,应用研究区域的地震活动性数据建立恰当的分布式地震活动性空间光滑模型,并结合断层对周边地震危险性的影响,计算前磨头断裂和衡水断裂在不同超越概率下上限震级分别为6.5、6.0级的区域基岩峰值加速度。研究发现,研究区域内50年超越概率为63%的基岩峰值加速度略有增加;50年超越概率为10%、5%的基岩峰值加速度在断层附近有所增加。研究表明在较低超越概率的情况下,断层周围如深州市、冀州市和衡水市辖区的地震危险性大于其他地区;利用仪器记录资料得到的地震活动性模型并结合断层资料计算出的地震危险性结果能够反映衡水地区现今的地震活动水平和危险性水平。

Using the historic seismic data and the fault properties,we calculate the regional peak ground acceleration（ PGA） in the study area with the spatial distributed seismicity model and segmented seismicity model in the probabilistic seismic hazard analysis（ PSHA） of Hengshui City. Considering the impact of the characteristics of the faults,we obtain the PGA distribution for63%,10% and 5% P. E. in 50 a of two scenario earthquake and find that the PGA for 10% and5% in 50 a increased visibly. It indicates that if the probability of exceedance is low,the seismic risk is greater in near-field region such as Shenzhou,Jizhou and the downtown of Hengshui City.The result shows that,the seismic activity model based on the instrumental earthquake catalogs with the characteristics of the faults reflects the contemporary seismic hazard level of Hengshui area.