历史强震震中精度统计特征及其对地震危险性研究的影响  

Statistical feature of epicenter accuracy of historical strong earthquakes and its effect on seismic hazard study

作　　者：吴清[1] 高孟潭[1] 徐伟进[1] 

机构地区：[1]中国地震局地球物理研究所,中国北京100081

出　　处：《地震学报》2012年第4期537-548,580,共12页Acta Seismologica Sinica

基　　金：科技部科技支撑项目"强震危险区划关键技术研究"(2006BAC13B01)资助

摘　　要：以《中国历史强震目录(公元前23世纪—公元1911年)》为基础,将目录中给出的震中精度参数在分段时间和分段震级上进行统计分析,并给出各类精度地震的地理分布.研究结果表明,58.4%的历史强震震中精度都在3类及以上,其震中不确定范围大于25km;一般来说,年代越久远的历史地震,其震中精度越差,而且公元1500年以后的历史强震低精度地震所占比例仍然不小;MS6.0以上的历史强震,3类、4类和5类精度地震占了60.1%;不同精度历史强震的地理分布各有特点,云南省1类、2类精度地震最多,而新疆和西藏的历史强震绝大部分都是低精度地震事件.以震中精度表述的历史强震震中位置不确定性会对潜在震源区划分、近场区地震活动性研究以及地震构造环境评价等工作造成影响,因此在地震危险性研究与地震地质工作中,都需对低精度历史地震重新考证或适当取舍.Based on Catalogue of Chinese Historical Strong Earthquakes （23rd century B.C. to 1911 A. D. ）, we statistically analyzed the epicenter accuracy parameters given by the catalogue in different time and magnitude intervals, and gave geographical distribution of the earthquakes with different categories of accuracy. The result shows that percentage of the historical strong earthquakes with the category 3 accuracy or above is 58.4%, with corresponding epicenter uncertainty being greater than 25 km. Generally speaking, the historical strong earthquakes have a low epicenter accuracy while they have a longer history. The percentage of low accuracy historical earthquakes is not small even after 1500 A.D. For the historical Ms^6.0 earthquakes the percentage of category 3, 4 and 5 events is 60.1%. The geographical distribution of historical strong earthquakes with different epicenter accuracies shows different characteristics. For example, Yunnan Province has the largest number of category 1 and 2 earth- quakes, while most historical earthquakes in Xinjiang and Tibet regions are low accuracy events. We also illustrated that the epicenter uncertainty of historical strong earthquakes may af{ect the results of potential seismic source delineation, near- field seismicity study and seismogeological environment assessment. So, in seis- mic hazard evaluation and seismogeological study, it is necessary to make textual criticism on the historical earthquakes with low epicenter accuracy, or appropriately reject some of them.

关 键 词：中国历史强震目录 震中精度 统计特征 不确定性 地震危险性 

分 类 号：P315.5[天文地球—地震学]