震前地震活动图象 1983年11月7日菏泽5.9级地震发生在聊城—兰考断裂带(以下简称聊考带)南段。1937年菏泽7.0级地震就位于5.9级地震震中附近,现今此断裂带的小震活动仍较活跃。 沿聊考带东西两侧各取50公里作为研究区域。依据台网控制能力,取震级下限为2.0,研究了此范围内1970—1983年11月7日5.9级地震前小震活动特征。发现5.9级地震前小震活动有以下异常现象。 Pre-earthquake seismic image November 7, 1983 Heze 5.9 earthquake occurred in Liaocheng - Lankao fault zone (hereinafter referred to chat zone) southern section. In 1937, the Heze 7.0 magnitude earthquake was located near the epicenter of the M5.9 earthquake. At present, the small earthquakes in this fault zone are still active. Along the chat test belt take 50 kilometers on both sides as the study area. According to the control ability of the station network, the lower limit of the magnitude is taken as 2.0, and the characteristics of small earthquakes before this M5.9 earthquake on November 7, 1970 to 1983 are studied. Before the M 5.9 earthquake, the following anomalies were observed.