[关键词]
[摘要]
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。
[Key word]
[Abstract]
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 for 63%,10% and 5% P. E. in 50a of two scenario earthquake and find that the PGA for 10% and 5% in 50a 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.
[中图分类号]
[基金项目]
中国地震局地壳应力研究所中央级公益性科研院所基本科研业务专项( ZDJ2013-13)、国家青年科学基金项目(41404044)共同资助