摘要
地表的断裂分布具有复杂的几何结构,分形几何学是定量研究断裂的复杂性和破碎性的一种数学方法。利用分维的方法,在比例尺为1:20万的安宁河断裂北段(西昌以北)的断裂分布图上,对断裂带各段的长度进行了测量,得到了各段的分形维值。测量结果冕宁大桥附近还有较大的维数(D_0=1.42),断裂北端维数值则相对较低(D_0=1.15),礼州一带和大桥一带相近(D_0=1.39)。作为断裂带的一个特征参数,分形维值与断裂带的力学性质、断裂运动、地震活动等有密切的关系。不同的力学环境中形成的断裂段有着不同的 D_0值:逆冲为主的断裂段 D_0值较低。在复杂断层背景上发展起来的活动走滑断层段有较高的 D_0值。
The fault distribution on the surface shows complicated geometrical structure.The fractal topogra- phy of faults is a mathmatical method to study quantitatively the complexities and fracture behaviours of faults.Using fractal method,on the 1:200000 map of fault distributon of the northern segment (in the North of Xichang) of the Anninghe fault zone,the length of each segment in the fault zone was measured and fractal dimention values of all segmtnts were abtained.According to the measured re- sults,there is relatively high value (D。=1.42) near Mianning Bridge and low value (D。=1.15) at the northern end of the fault.The value (D。=1.39) in the vicinity of Lizhou is similar to that near Mianning Bridge. As a characteristic parameter of fault zone,fractal demension value is closely related to the me- chanical behaviour,the fault motion and the seismicity in the fault zone.The fault segments which formed in defferent mechanical conditions have different D。values:the D。value of the fault segment showing mainly thrust behaviour is relatively low and the D。value of active strike—slip fault devel- oped in the setting of complex fault system is relatively high.
出处
《四川地震》
1991年第1期31-36,共6页
Earthquake Research in Sichuan
