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甘肃东南景泰—海原—陇西—永登—带是历史上强震从集发生的地区。1995年7月22日永登5.8级地震是本地区平静近五年的第一个5级地震,从而显示出本地区的地震活动在平静了50年之后又开始活动。本地区位于黄河上游,峡谷丛生地貌复杂。其地质构造为陇西旋卷构造,大体上接近巨型东西构造带和西北构造带的汇合部位,还有河西系北北西向断裂穿越,所以区域应力状态比较复杂。这次永登5.8级地震前断层形变测点有较好的中短期前兆异常。因此这次震例分析对于识别和提取地震前兆信息,以及做好本区今后的强震预测工作有着积极意义。
The areas of Jingtai-Haiyuan-Longxi-Yongdeng-belt in the southeast of Gansu are the areas where historical strong earthquakes occurred. The July 9, 1995, Yongdeng M (subscript S) 5.8 earthquake was the first M5 earthquake to calm in the region for nearly five years, which shows that the seismogenic activities in this area started to reopen after being calm for 50 years. The region is located in the upper reaches of the Yellow River, gorge complex complex landscape. Its geological structure is the Longxi rotational volcanic structure, which is generally close to the confluence of the giant east-west structural belt and the northwest structural belt, and the Hexi Corridor crosses the north-northwest fault. Therefore, the regional stress state is rather complicated. The rupture point before the Yongdeng M 5.8 earthquake had better short-term and short-term precursor anomalies. Therefore, this earthquake case analysis has positive significance for identifying and extracting the information of earthquake precursors and doing a good job of predicting strong earthquakes in the future.