Abstract: The information of tectonic movement in the earthquake-stricken areas of the 1979 M_S 6.0 Wuyuan earthquake,the 1989 M_S 6.1 Datong-Yanggao earthquake and the 1996 M_S 6.4 west Baotou earthquake are studied by using multi-phase and multi-channel satellite images. Furthermore,the geologic-tectonic background of these earthquakes is discussed by combining the obtained results with the existing seismic intensity investigation data. The results of this study show that the 1979 M_S 6.0 Wuyuan earthquake occurred at the convergence of the NE-trending Haiziyan Fault and the NW-trending west Wuyuan Fault,as indicated by tone difference and micro-morphologic features on satellite images. The long axis of the high intensity isoseism of this earthquake is NE-trending,consistent with the Haiziyan Fault,which is therefore assumed to be the seismogenic fault of this earthquake. The long axis of the low intensity isoseism of this earthquake is NW-trending,indicating the effect of the NW-trending west Wuyuan Fault. The 1989 M_S 6.1 Datong-Yanggao earthquake occurred on the NEE-trending Dawangcun-Xi'anquan Fault which extends from the hinterland of the Liulengshan Mountains to Datong-Yanggao basin,as indicated by micro-morphologic and tone differences on the satellite images. The fault is consistent with the long axis of the isoseism of this earthquake as proposed by Su Zong-zheng et al. The 1996 M_S 6.4 west Baotou earthquake occurred at the convergence of the Wulashan north marginal fault and the NW-trending Xinsheng Sand Yard Fault,as indicated by distinct scarp and groove landforms. The long axis of high intensity isoseism of this earthquake is NE-striking,sub-parallel to the NEE-trending Wulashan north marginal fault that is assumed to be the seismogenic structure of the west Baotou earthquake. The long axis of low intensity isoseism of this earthquake is NW-striking,which is considered to be the effect of the NW-trending Xinsheng Sand Yard Fault.

Key words: north margin of Ordos, fault basin region, strong earthquake preparation, satellite remote sensing image, seismogenic structures

摘要： 利用多时相、多波段卫星图像,研究1979年五原6.0级地震、1989年大同-阳高6.1级地震和1996年包头西6.4级地震震区的构造活动信息,结合前人的烈度调查资料,探讨这些强震发生的地质构造环境。研究表明:1979年五原6.0级地震发生在NE向海子堰断裂与NW向五原西断裂交会的部位。五原6.0级地震高烈度区等震线长轴呈NE向,与海子堰断裂一致,是五原地震的发震构造。1996年包头西6.4级地震发生在由陡崖和沟槽地貌显示的NEE向乌拉山北缘断裂与NW向新生砂石厂断裂交会的部位。包头西6.4级地震高烈度区等震线长轴呈NE向,与乌拉山北缘断裂接近,该断裂是包头西6.4级地震的发震构造。2次地震高烈度区长轴与低烈度区长轴走向相差近90°,这是因为除发震构造外,烈度区还受一组与之交会的共轭断裂活动的影响。1989年大同-阳高6.1级地震,发生在从六棱山腹地向大同-阳高盆地延伸的NNE向大王村-西要泉断裂上,该断裂是大同-阳高地震的发震构造。

关键词: 鄂尔多斯北缘, 断陷盆地区, 强震孕育, 卫星遥感影像, 发震构造