弱震区弱活动断裂的地震危险性评价——以丹江断裂为例

Assessment of Seismic Risk of Weakly Active Faults in Weak Seismic Background Region:Taking Danjiang Fault as an Example

如何评价弱震区弱活动断裂的最大潜在地震震级及其危险性是地震中长期预测和地震区划研究中较为重要的问题之一。借鉴闻学泽等[1]对中国大陆东部中-弱活断层潜在地震最大震级评估的思路,对丹江口核心水源区已发最大地震震级M_(max)与断层小区震级-频度参数at/b值之间的关系进行统计分析。综合at/b值与最大地震震级上限Mu经验公式计算结果、老河口潜在震源区震级上限以及断裂活动性判断,丹江断裂的震级上限为MS6.0,并利用泊松模型方法评估了该断裂的地震平均复发间隔和发震概率。

An important problem in long-term prediction and seismic zonation analysis is how to evaluate the potential seismic risk of weakly active faults in weak seismic background.The authors refer to the method that Wen advances to estimate magnitudes of maximum potential earthquakes in sub-areas of the moderately and weakly active faults in eastern Chinese mainland.We build the empirical relationship between the maximum magnitudes M_（max）and the at/b values of the sub-areas＇ frequency-magnitude relationships.With the empirical relationship,the upper-limits Muof the Danjiang fault in Laohekou fault area is M_S6.0.The average interval recurrence time and the probabilities of destructive earthquake on the fault is evaluated with Possion model.