南北地震带北段主要断层的分区强震危险性评估

Strong earthquake risk evaluations on major fault subzones in northern section of the North-South Seismic Belt based on the time-and magnitude-predictable model

摘要:

根据时间-震级可预测模式研究中国南北地震带北段断裂系统的地震复发规律，利用历史地震记录和断层滑动速率资料计算得出区域时间可预测统计模型和震级可预测统计模型，并对4个主要潜在震源区在未来10年内的强震复发危险性进行概率评估。计算结果表明，危险性最高为S1区（海原断裂带），其综合危险率K值为0.841，预测下次主震为6.9级；其次为S2区（天桥沟-黄羊川、香山-天景山、六盘山断裂带等），K值为0.480，预测下次主震为6.4级；S3区（祁连山构造带）和S4区（西秦岭构造带）远低于S1和S2区。按照危险程度排序的前2位均位于东祁连山-六盘山构造带。

Abstract:

The law of earthquake recurrence in the northern section of North-South Seismic Belt fault system is studied based on the time-and magnitude-predictable model,and the corresponding time-and magnitude-predictable statistical formulae have been obtained by using the historical earthquake records and the fault slip rate data,then the strong earthquake recurrence probabilities of 4 major potential seismogenic subzones within the next 10 years are assessed. The calculation results show that the highest risk is in the Haiyuan fault belt(S1 subzone)with the integrated risk rate K=0.841,and its forecasted next main earthquake is M6.9. The second is the S2 subzone(the Tianqiaogou-Huangyangchuan fault belt,Xiangshan-Tianjingshan fault belt,Liupanshan fault belt,etc.)with K=0.480,and the forecasted next main earthquake is M6.4. The K values in the S3(Qilianshan tectonic belt)and the S4 subzones(West Qinling tectonic belt)are far lower than those in the S1 and the S2 subzones. The top 2 risky subzones are all located in the east of Qilianshan-Liupanshan tectonic belt.