华北地区深、浅部应力状态的差异及其成因研究  

Differential Tectonic Stress Pattern Between the Deep and Shallow Crust in North China and Its Possible Genesis

作　　者：梁海华[1] 刘树文[1] 侯建军[1] 常祖峰[1] 

机构地区：[1]北京大学地质学系,中国北京100871

出　　处：《中国地震》2000年第1期69-76,共8页Earthquake Research in China

摘　　要：在分析和评价各种应力资料的基础上 ,从三维空间分析应力图象的差异性 ,并从边界条件和岩石圈介质的不均一性出发 ,提出华北地块构造应力双层模式。然后用有限元方法进行了模拟 ,计算结果与实际资料相当吻合 ,即以 10km左右深度的滑脱面为分界 ,其下存在一个比较一致的以近水平的北东 北东东的最大主压应力为特征的挤压应力场 ,而滑脱面之上的浅部地块内主应力方向的一致性很差 ,总体上反映出多方向伸展的格局。计算得到的剪应力分布有助于对大震震源位置的预测。This paper approaches to the subject of the neotectonic stress field from the data of focal mechanism solution, ground stress measurement, tectonic mechanical analysis and geodetic surveying, and finds out that the orientations of the maximum principal compressive stress patterns are quite discordant with different methods and the stress patterns are widely different from the shallow part to the depth of the crust in North China.Based on the analysis of above\|mentioned data, we established a duplex model by considering the diversities of the stress patterns in 3\|dimentional space, the boundary conditions and the lithospheric media, and make an inverse calculation by finite element method. The calculated resuts fitted well with the reality in North China,i.e.the stress patterns in lower crust which is below the detachment interface at the depth of 10km from ground surface are relatively consistent with nearly horizontal state and NE\|ENE trending of the maximum principal compressive stress axes, whereas the stress patterns in upper crust which is above the detachment interface are widely divergent with extensional state in polydirections. Therefore, small earthquakes are prone to occur in the shallow part while large earthquakes are generated in the lower crust. The hypocentral location for a potential large erathquake may be inferred from the shearing stress distribution calculated by finite element method based on the duplex model.

关 键 词：华北地区 应力状态 滑脱面 华北地块 构造成困 

分 类 号：P544[天文地球—构造地质学] P542.3[天文地球—地质学]