首都圈地震危险区划分及未来强震地点预测研究

THE ZONATION OF SEISMIC RISK AREA AND ANTICI- PATION OF COMING STRONG EARTHQUAKE SITES IN THE CAPITAL CIRCLE AREA

本文以最新的断层活动性资料为基础,采用定性、定量、综合三种方法评估研究区的强震危险性。定性的方法即断层活动性与强震构造相结合的分析方法。根据区内25条主要活动断裂进行最新活动时代、活动性质、活动性分段、破裂分段的分析与鉴定的结果,结合断层本身的强震构造标志,对发震断层进行危险性分类。定量的方法即强震消逝率的计算方法。为了解决6—7级地震的危险性预测问题,在活断层资料基础上,建立了研究区中强震重复率(R)与震级(M)及断层活动速率(V)的统计关系。综合评价的方法即断层地震危险度的综合评定法。在评定断层地震危险度时,引进了断层能动度、失稳度的评价方法,解决了断层无震或小震蠕滑和滑动闭锁段的评价和预测问题。本文最后把三种方法的评价、预测结果进行综合分析,使之互相验证、互相补充,提高了最终预测结果的可靠性。 所作的强震预测包括三个要素:强震的地点(范围)、震级档次及发震时间的逼近度(分等级)。

Based on a great deal of reliable and the newest data of fault activity, this paper applied three methods, i. e. the qualitative, the quantitative and synthetical ones, to evaluate the risk of strong earthquakes in the research area. The qualitative method is an analytical one combining the fault activity with the strong seismic structure. On the basis of the analyzed and identified results of 25 faults in the area, including the newest activity, active time, activity and fracturing segmentation and combining with their tectonic marker of strong earthquakes, the risk of seismogenic faults is classified. The quantitative method is to calculate the passing-away rate of strong earthquake. For evaluating the risk of earthquakes with M = 6-7, a statistical correlation between strong earthquake reccurence inteval (R) and magnitude (M) or fault slip rate (V) is built up based on abundent and relieable active fault data in the area. The synthetical method is a comprehensive assessment one for the earthquake risk degree of the faults. The synthetical methods to evaluate the fault capability degree and instability degree is assumed to anticipate the seismic risk of the creep-slipping segment and locked segment with small earthquakes or without seismicity. At last, the evaluated and anticipated results of three methods are comprehensively analysed, verified and replenished each other to increase the reliability of the last anticipated result. The anticipated strong earthquakes include three elements: site, magnitude interval and approachting degree in time.