祁连山中东段断裂的地震危险性分析

ANALYSIS ON SEISMIC RISK FOR FAULTS IN THE MID-EASTERN QILIANSHAN AREA

摘要:

利用祁连山中东段活动断裂的定量参数和"时间相依"的概率模型,对该地区断裂在未来一定时段内的发震概率进行了分析.认为该地区老虎山-毛毛山断裂的毛毛山段和金强河段的发震概率较高,其他断裂的发震概率很低;未来10年和20年,毛毛山段的发震概率分别为15.76%和29.03%,金强河段的发震概率分别为15.33%和28.41%,2段联合发生7.5级地震的概率分别为28.67%和49.19%.未来50年2段联合发生7.5级地震的概率为81.79%;通过对兰州地区1125年7.0级地震破裂带遗迹的考察,得出马衔山断裂未来50年发生M_S ≥ 7.0地震的概率为19.87%.

Abstract:

The recurrence probabilities of earthquakes for faults in future in mid-eastern Qilianshan area are analyzed by using quantitative data for the active faults which are obtained by the authors and other men of learning in recent years and the probability model depending on time,based on improving the precisions of the quantitative data.The results are as follows:(1)The recurrence probabilities of strong earthquake on Jinqiang river and Maomaoshan segments of Laohushan-Maomaoshan fault are higher.Except the two segments,the probabilities of M_S ≥ 7.0 earthquakes on faults in the area are nearly zero in future 100 years.(2)The probabilities of strong earthquakes on the two segments are 15.76%, 29.03% and 15. 33%,28.41%respectively and the probabilities of the two segments together are 28.67%and 49.19% respectively in future 10 and 20 years.Infuture 50 years,the probability of M_S7.5 earthquake on the two segments together is 81.79%.(3)The probability of M_S ≥ 7.0 earthquake on Maxianshan fault in future 50 years is 19.87%.