断层位错引起的地表重力变化特征研究

CHARACTERISTICS OF SURFACE GRAVITY CHANGES CAUSED BY A FAULT OR FAULTS DISLOCATION

基于均匀、各向同性、无限弹性半空间中有限矩形断层位错引起的地表重力变化的理论,研究了单一断层和两条断层组合错动引起的地表重力变化图像的特征。得到:1)在1条断层错动引起的地表重力变化中,地表高程变化对其影响最大,密度变化和水平位移变化的影响相对较小;断层埋深、倾角、错动量的大小和错动方式均对地表重力变化图像的影响较大;2)对两条断层组合情形,断层同一深度分布时,地表重力变化与断层之间的相对位置密切相关;断层不同深度分布时,地表重力变化主要受浅部断层的影响,但深部断层错动也可能对地表重力变化产生较大的影响。

According to the theory of gravity changes caused by dislocation on a rectangular plane buried in a homogeneous elastic half-space the characteristics of surface gravity changes caused by one fault or combination of two faults are studied. The main conclusion are ： I ） For one fault, the effect of surface elevation change is larger than the effect of density change or horizontal displacement change. The depth of the fault, the dip angle, the magnitude of dislocation（ U1 ,U2 , U3） and the way of dislocation have also large effects on the surface gravity change; 2） For the combination of two faults, when they are in the same depth, the relative position of the faults have great effect on the surface gravity changes, when they are in different depth, the shallow fault plays a dominant role in the total surface gravity change, but the deep fault may also have great effect on it if the deep fault has different characters.