新疆地区典型潜在震源区大震年发生率的估计

利用活动断裂定量研究资料（滑动速率、古地震等）,结合新疆地区的地震构造环境特征分析,研究了典型潜在震源区大震复发模式,建立了具有区域特征的混合模型,以此评定了新疆地区典型潜在震源区大震的年发生率。混合模型由截断G-R关系模型和特征地震模型构成,计算时先分别计算两个模型的大震分震级档年发生率,然后根据潜在震源区地震地质资料的完备性情况、可靠程度以及大震孕育的区域性特征为两个模型的分震级档结果赋予一定权重,最后求两个模型的加权和。大震复发间隔的计算中利用汶川地震与集集地震的最大垂直位错和平均垂直位错统计关系约束了逆冲型断裂的平均位错量,潜源区的大震年发生率的计算考虑了级联破裂问题。结果表明,本研究所得高震级档大震年发生率比第三代、第四代地震区划图小,文中对这一现象产生的原因进行了初步分析。

Annual Reoccurrence Rate of Large Earthquake in Typical Potential Seismic Zone of Xinjiang Region

By using fault quantitative data （slip rate and paleoearthquake sequence et al.）,accompanied by the analysis of regional seismotectonic background, we develop combined models in which the regional characteristics are considered. The annual rate of large earthquakes of typical Potential seismic Zone in Xinjiang region is estimated with our models. The Combined model consists of two recurrence models： Cut-Off G-R relationship model and characteristic earthquake model. In application the annual rates of sub-magnitudes are calculated respectively at first, then weight of each factor is assigned according to the completeness and reliability of quantitative data and regional characteristics of seismological background, Finally the weighted values are summed up. A relationship between maximum and average displacements is derived from Wenchuan MS 8.0 earthquake and Chi-Chi MW 7.6 earthquake respectively and used to constrain the average displacement of Manas 1906 earthquake. The result shows that the annual rate of large earthquake are smaller than that of China seismic zonation maps both of the third and the fourth generation. the reasons for this instance are analyzed in this paper.