摘要
根据１９９２年和１９９５年两期ＧＰＳ测量结果所获得的位移场和应变场，结合丰富的地质资料，利用有限元方法对华北地区现今构造应力场进行了数值模拟。计算结果表明：华北地区现今构造应力场主压应力方向为ＮＥＥ，其边界力除受ＮＥ５５°～ＳＷ２３５°方向的压应力作用外，同时还受到ＳＥ１２０°～ＮＷ３００°方向的拉张力作用，其中ＮＥ－ＳＷ的压应力量值较大，约为ＳＥ－ＮＷ向拉应力的两倍，这个结果与震源机制解所获得的应力场方向基本一致。这一应力场状态是两种动力学过程的叠加：一是印度板块和太平洋板块的挤压，其中来自印度板块的作用力最大，约为太平洋板块作用力的１．５倍；另一个是因地幔隆起而产生的ＮＷ－ＳＥ向的水平拉张力。
According to the displacement and strain field obtained by GPS in 1992 and 1995 and combining with the abundant geologic data, the present tectonic stress field in North China, as a plane strain problem, is simulated numerically by means of the finite element method. The results show that the trend of main press stress of present tectonic stress field in North China is in NEE, and its boundary forces are influenced by the tensile stress (SE120°～NW300°) besides the pressure stress (NE55°～SW235°), in which the pressure stress is about twice as big as the tensile one. The simulative trend is corresponded basically with the stress field direction determined by the focal mechanism solution. The driving force of pressure stress in NE55°～SW235° trend seems to be mainly due to the press of the Pacific Plate and Qingzang Plateau and the drive of the Indian Ocean Plate which is about 1.5 times larger than the press of the Pacific Plate, while the tensile stress of SE-NW trend is related to the tensile mechanism resulted from the upheaval of upper mantle.
出处
《地壳形变与地震》
CSCD
1999年第2期81-89,共9页
Crustal Deformation and Earthquake
基金
国家自然科学基金
关键词
GPS
构造应力场
数值模拟
华北地区
GPS, present tectonic stress field, numerical simulation, North China
