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根据大地测量学、地质学、地形学和地震数据,对亚洲地区(平均深度约100 km)垂向平均偏应力场进行了简单的新的动力学计算。通过解岩石层内与重力势能差有关的偏应力平衡方程和应力边界条件产生的一阶偏应力,我们可以初步得到对垂向平均偏应力的最小绝对强度和方向的估计。这种垂向平均偏应力场的初始估计与关于岩石层流变性的假设无关。其绝对值从5 MPa 变到40 MPa。假设岩石层有明显的粘滞性,与该区域其他较硬地方约1～2.5×10~(23) Pa s 的粘滞系数相比,由偏应力强度、GPS 和第四纪断层滑动速率得到的应变率,导出了西藏垂向平均粘滞系数为0.5～5×10~(22) Pa s。利用速度边界条件解力平衡方程的正向模拟,我们能改进对垂向平均有效粘滞系数分布和偏应力场的估计。总的垂向平均偏应力和有效粘滞系数场与西藏较软弱的下地壳是一致的,它们也与西藏和华南岩石层相对欧亚的东向运动一致,它们确证了重力势能差对青藏高原周围应变率的空间变化方式和强度有极深刻的影响。我们的垂向平均偏应力的结果表明,较强的岩石层部分位于孕震的上地壳内,其偏应力强度高达100～300 MPa(与实验室和理论摩擦试验一致,显示出地震的应力降是总偏应力的小部分)。
Based on geodesy, geology, topography and seismic data, a simple new kinetic calculation of the vertical average deviatoric stress field in Asia (average depth of about 100 km) has been performed. By solving the deviatoric stress balance equation and the first-order deviatoric stress caused by the stress boundary conditions in the lithosphere, we can initially obtain the minimum absolute strength and direction of vertical deviatoric deviations. This initial estimate of the vertical mean deviatoric stress field has nothing to do with the assumptions about lithospheric rheology. Its absolute value changes from 5 MPa to 40 MPa. Assuming that the rock layer has a marked viscosity, compared with the viscous coefficient of about 1 ~ 2.5 × 10 ~ (23) Pa s at other hard places in this area, it is obtained from the deviatoric stress intensity, GPS and the slip rate of Quaternary faults , The vertical average viscosity of Tibet is derived as 0.5 ~ 5 × 10 ~ (22) Pa s. Using the forward modeling of the solution balance equation for velocity boundary conditions, we can improve estimates of the vertical average effective viscous coefficient distribution and the deviatoric stress field. The total vertical deviatoric and effective viscous coefficient fields are consistent with the weaker lower crust in Tibet, and they are also consistent with the eastward movements of the lithosphere in Tibet and South China relative to Eurasia. They confirm that the difference in gravitation potential over the Tibetan Plateau There is a profound impact on the way and intensity of the spatial variation of the strain rate around it. The results of our average vertical deviatoric stress show that the stronger part of the lithosphere is located in the upper crust of the seismogenic earthquake and its deviatoric stress is as high as 100-300 MPa (consistent with laboratory and theoretical friction tests, showing that the stress drop Is a small part of the total deviatoric stress).