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任丘油田位于河北省任丘县、华北平原冀中坳陷的次级构造单元一饶阳凹陷内。由于其特殊的应力条件和地质条件,使其成为地质和力学结构上的簿弱点。油田的开发和高压注水,使其有效应力值进一步降低,发生了诱发性小震群活动,最大震级M_s=3.3。在华北地区发生中强地震前,该区小震群活动有明显增强现象,这种特点与华北地区5～7级大震前出现小震群活动的特点相一致。该区是华北块体大范围的统一应力场作用下,反应地壳应力变化的敏感点,可以作为监测华北地区震情变化的一个“窗口”。
Renqiu Oilfield is located in Renqiu County, Hebei Province, North China Plain Jizhong depression secondary structural unit within a Raoyang depression. Due to its special stress conditions and geological conditions, it has become a weakness in geology and mechanics. The development of oilfield and high-pressure water injection further reduced the effective stress value, and induced small swarm swarm activity with the maximum magnitude of M_s = 3.3. Before the occurrence of the moderate-strong earthquake in North China, the activities of small swarms in this area have been significantly enhanced. This is consistent with the characteristics of the small swarm swarms that occurred before the earthquakes of magnitude 5 to 7 in North China. This area is a sensitive point to respond to the change of crustal stress under the influence of a large range of unified stress field in North China block, which can be used as a “window” to monitor the change of earthquake conditions in North China.