哈尔滨市主要断裂未来地震危险性评价

EARTHQUAKE RISK ASSESSMENT OF THE MAIN FAULTS IN HARBIN URBAN AREA

哈尔滨市目标区内主要断裂断错地表的最新活动时代为第四纪早期,晚更新世以来无断错地表的活动迹象。通过对城市活动断层地震危险性评价的技术思路、哈尔滨市工作区的地震地质环境与潜在震源区划分、目标区主要断裂活动特征的综合分析,确定了目标区内3条主要断裂未来可能发生地震的最大震级,并以兴安-东蒙活动地块与工作区作为分析的两种范围尺度,在适当调整工程地震学地震危险性概率分析方法的基础上,综合估算了目标区和目标区内单条断裂未来100年的发震概率。结果表明:哈尔滨市目标区主要断裂未来发生4.0级上破坏性地震的可能性极小,可能地震的最大震级为MS5.5。

In the target area of active fault surveying around Harbin City, the latest rupturing ages of the main faults are all early or middle Pleistocene, and there are no evidences to indicate that rupture has occurred on these faults since late Pleistocene. By synthetical analysis of technical route of earthquake risk assessment of urban active fault, seismic environment and division of potential seismic source zone in research area around Harbin City, and activity characteristics of the main faults in target area, the maximum magnitude of probable future earthquake on these main faults are forecasted in this paper. And then probabilities of middle-strong earthquake occurring in the next 100 years are calculated for both the whole target area and its three single faults according to the two scales of Xin＇an-Dongmeng active block and research area on the basis of adjusting properly the probability technique of earthquake risk analysis for engineering seismology. In conclusion, the probable future maximum magnitude on the main faults in target area are all Ms 5.5, but there is bally low probability of damaging earthquake（Ms 〉 4） occurring on them. No doubt, there are still a few uncertainty and unreliability to these results statistic. However, in terms because of the hypothesis for of current level, the technique calculation and deficient samples for of earthquake risk assessment in this paper is more suitable to use for such still areas as Harbin, where the tectonic activity is quite weak since late Quaternary. And furthermore, it can provide at a certain extent tutor or reference for surveying and prospecting of active fault in other cities.