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选择北纬38°—41°30′,东径114°20′—120°20′范围为模拟地区,其中包括12条断层和一个硬块体,假定断层为不抗拉介质,在压应力作用下能承受剪应力。采用物理非线性有限单元法,模拟上述地区在压应力作用下的地震孕育过程。为了简化计算,化为平面应变问题。数学模拟结果与地形变和震源机制等资料较吻合,本文的主要结果为:(1)唐山地震孕育过程中区域应力场的时间变化。(2)唐山地震孕育体的形成过程。(3)震前主应力轴的旋转。(4)唐山地震的初始破裂区。(5)地温变化在大震发生中的突变性作用。
Select the latitude 38 ° -41 ° 30 ’north latitude, 114 ° 20’-120 ° 20’ east range of the simulation area, including 12 faults and a hard block, assuming that the fault is not a tensile medium under the effect of compressive stress To bear the shear stress. The physical nonlinear finite element method is used to simulate the geocentric gestation process under the compressive stress in the above areas. In order to simplify the calculation, into a plane strain problem. The results of mathematical simulation are in good agreement with the data of topography and source mechanism. The main results of this paper are as follows: (1) The temporal variation of regional stress field during the gestation of Tangshan earthquake. (2) Formation of Tangshan Earthquake. (3) rotation of principal stress axis before earthquake. (4) The initial rupture zone of Tangshan earthquake. (5) The mutational effect of the change of ground temperature in the occurrence of a major earthquake.