菏泽5.9级地震极震区、构造背景和发震构造的初探

本文根据菏泽震区41个自然村实测宏观地震烈度和24个自然村震害指数资料对比,表明菏泽5.9级地震极震区的宏观烈度与震害指数的符合率达80％,并根据震害的宏观烈度资料,确定菏泽5.9级地震宏观震中为前刘庄和后刘庄一带,震中烈度为Ⅷ度,震害指数(j)W分别是0.2、0.22。极震区宏观烈度Ⅶ度至Ⅶ度弱,震害指数大于或等于0.1,小于0.3。文中指出极震区等烈度线形态具有东西和北东分布的两重方向展布特征,认为此形态特征主要受控于菏泽震区的地震构造。据等烈度线形态、地震活动的空间分布、震区表层和深部构造资料等表明,菏泽震区具有特定的地壳结构和不均一的介质块体孕震构造条件,并指出聊考断裂带与菏泽断裂带的复合部位是菏泽4次强、中强地震的发震构造。

A PRELIMINARY STUDY ON THE TECTONIC SETTING AND GENERATING STRUCTURES OF THE MEIZOSEISMAL AREAS OF HEZE EARTHQUAKE (Ms=5.9)

Based on the comparison of macroscopic seismic intensities from 41 villages and the statistics of average damage indices to the buildings of 24 villages in Heze seismic area, the coincidence rate between macroseismic intensity and damage index is about 80％. The macroseismic epicenter is determined at Qian Liuzhuang and Hou Liuzhuang, with epicentraI intensity Ⅶ, corresponding average damage indices (ⅰ) w 0.2 and 0.22 respectively. The iso-intensity lines of meizoseismal area are characterized by extending toward both EW and NE directions. Based on the shape of iso-intensity lines, the spatial distribution of seismic activities, and the superficial and deep structures of the seismic areas, it is inferred that there is a special crustal structure and a nonhomogeneous medium massif in Heze seismic area, which are the factors of earthquake-generating structures.