华北地区重力势能差水平构造应力分布特征

摘要

We calculate vertical integrated horizontal deviatoric stresses by solving force balance equations in a thin sheet approximation involving gravitational potential energy terms through a finite element method.GPE values,eliminated the effects of dynamic topography,are derived from the Crust 1.0 model,the V24.1 gravitational model and the V18.1 topography model data sets.The results show that GPE in north China area presents aspatially heterogeneous distribution.Areas in high values of GPE are tensile,whereas compression exists in regions of low values of GPE.The GPE shows high values occurring at the north central area of Yinshan mountain-Yanshan mountain fault block,where the direction of maximal horizontal tensile stress is N-S.The orientation of maximal horizontal principal compressional stress in low values of GPE,such as the northeast and southwest of the north China plain block and the north areas of central Hehuai plain,is dominated by NWW-EES.%采用Crust 1.0地壳模型、SIO V24.1重力场模型和SIO V18.1地形模型计算华北地区的重力势能,并进行动力地形改正以消除岩石圈下地幔运动产生的径向作用力对重力势能的影响.利用有限元方法求解重力势能与水平构造应力之间的平衡方程,得到华北地区的水平构造应力分布.结果表明,华北地区水平构造应力空间分布不均匀,高重力势能区表现为引张状态,低势能区为压缩状态;阴山-燕山断块中北部为高势能区,张应力以N-S方向分布;华北平原断块西南部卫辉周围、东北部葫芦岛和秦皇岛一带以及河淮平原断决西北部郑州附近为低势能区,最大主应力方向为NWW-SEE.