1989年大同—阳高地震的地质环境与地震构造

The Geological Environment and Seismotectonic of the Earthquake in Datong-Yanggao Area in 1989

1989年10月18日的大同—阳高地震发生于大同盆地的册田凹陷。册田凹陷走向北东东,其南缘的六棱山断裂为凹陷的主干断裂,是这次地震的控震断裂。该凹陷内发育北东向和北西向两组断裂,其中大王村断裂和团堡断裂规模最大。这两条断裂大部份隐伏于新生代沉积层之下。电法勘探、钻探、泉的分布及地貌现象均显示其展布位置。在北东东向区域压应力场的作用下,这两条断裂成为此次地震的发震断层。震源机制解结果和烈度分布特点支持上述结论。

The Datong -Yar.ggao earthquake on October 18,1989 occurred in the Cetian Hollow of the Datong Basin,the strike of which is north -cast -east and Liulengshan Fault at the southern c-dge of which is the trunk fault controlling the earthquake. In the hollow two groups of faults-one being nertheast and the other north -west-are developing,a-mong which the Dawang Village Fault and the Tuanbao Fault are the Largest. Most parts of the two faults are hidden under the sedimentary layer of the Cenzoic Era. Electric surveys,prospecticn drillings,the distribution of springs and their land features-all these show their areal location. These two faults became the seismogenie fault of the earth-quabe under the compressive stress field. The sbove conclusion is supported by the focal - mechanism solution and intensity distribution features of the earthquake.