正断层位移长度关系及其研究意义

The displacement-length relationship of faults and its significance

正断层位移长度关系是近年来研究正断层的一种常用方法 ,它将断层的研究从二维扩展到三维。研究正断层位移长度关系对于研究正断层演化、盆地演化以及油气勘探等方面具有重要意义。讨论了影响正断层位移距离剖面形态的主要因素 :断层端的脆韧性变形、围岩强度、远程应力以及断层之间的相互作用和连接等。根据正断层位移距离剖面的几何形态和断层发育阶段 ,可将断层的位移模式分为 3个类型 :(1)对称的椭圆状或钟状代表简单的单条断层 ;(2 )不对称的似椭圆状或钟状代表断层间的相互作用 ;(3)不规则的锯齿状代表由多条断层连接而成的断层。介绍了伴随正断层发育的传递斜坡、盆内高地等构造单元以及断层位移距离剖面的测量制作方法。测量时应注意恢复其剥蚀部分。

Displacement-length relationship is a common method in research on normal faults in recent years. It provides a basis for extrapolating a two-dimensional view of faults into the third dimension. The authors present some factors that influence the geometry of the displacement-distance profiles of normal faults,such as the plastic deformation in the end of faults,host-rock stiffness, remote tensile stresses, and the interaction and linkage of faults. According to the geometry of the displacement-distance profiles and the stages in the development of normal faults, the authors separate the pattern of displacement into three classes: (1) symmetrical elliptical or bell shaped for single simple faults; (2) asymmetrical elliptical or bell shaped for interactive faults; (3) serrated shaped for linked faults. The authors describe some structures that are formed simultaneously with the fault, for instance the relay ramps, the intrabasin high, and so on. These structures are corresponding to the position of the interaction and linkage of faults. There are two kinds of method of measuring the displacement and length of faults as follows: measuring is done on the surface, and the other is on the subsurface. Note that the eroded part needs to be reconstructed before the faults are measured. It is of great significance to study the displacement-length relationship for faults in the development of basin, the evolution of faults and hydrocarbon exploration.