确定潜在震源区地震年平均发生率的方法研究

THE RESEARCH ON DETERMINING THE ANNUAL OCCURRENCE RATES OF POTENTIAL SEISMIC SOURCE AREAS

为了在地震危险性分析方法中,较好地反映大陆内部地震活动的时空不均匀性,按照震级分档和空间概率分布函数的思路,本文选取并量化了多个地震、地质特征,以描述各震级档地震活动在时间上和空间上的性质.为避免同一因素的重复使用和主观作用的介入,文中引入了分量分析方法对特征进行正交变换.对变换得到的互不相关的新特征进行模糊综合评判,再结合七级以上强震发生后的减震作用,确定了各潜在震源区各震级档的地震年平均发生率作为例子,试算了京-津-唐-张地区的地震烈度区划图.该例子说明,本文的分析方法,不仅能反映华北地区地震活动的时空不均匀性。

To actually reflect the seismic temporal-spatial inhomogeneity of intracontinental strong earthquakes of North China in seismic hazard analysis, several seismological and geological characteristics have been selected and quantized to describe the seismicity features in time and space of every magnitude interval with the thought of dividing the interesting magnitude range into several intervals and using of the spatial probability distribution function. A component analysis method with orthogonal transformation is introduced to avoid the repeated use of the same element and the subjective effects in determining the annual occurrence rates. By passing synthetic fuzzy judgement on the nonintercorrelated new characteristics, the annual occurrence rates of every magnitude interval of each potential source area are obtained associated with the adjustments of earthquake reducing process after the occurrence of M>7 quake. An intensity map of the Beijing-Tianjin-Tangshan-Zhangjiakou area is calculated as an example which shows a close coincidence with the seismic temporal-spatial inhomogeneity of North China.