几次大地震前后地电场中长期变化分析与研究

地电场是地球表面天然存在的电场, 包括大地电场和自然电场。 利用“合成能量累加”方法, 分析处理了甘肃省、 青海省、 四川省、 重庆市所辖部分台站2007年7月至2017年12月的地电场观测数据, 研究和讨论了汶川8.0级地震等几次大地震前后地电场中长期异常变化特征。 研究结果显示, 几次M_S7.0以上大地震前后, 均出现了地电场区域性准同步异常变化; 地电场异常变化经历了“震前—发震—震后”三个阶段, 震前和震后变化比较明显, 发震期变化相对平稳, 时间跨度达12个月以上; 地电场异常变化主要沿构造带分布, 变化强度随震中距的增加而减小。

Immediate to Long-term Changes of Geoelectric Potential Difference before and after Several Large Earthquakes

The geoelectric field is a natural electric field on the surface of the earth, including the telluric field and the spontaneous potential field. This paper used the new method of the synthesis energy accumulation, studied and discussed the variation characteristics of the Long-term geoelectric potential difference observed from stations from Gansu, Qinghai, Sichuan provinces and Chongqing municipality, before and after the several large earthquakes during July 2007 to December 2017. The results show that: ① There were quasi-synchronous geoelectric field abnormal changes before and after the above M_S7.0 level large earthquakes; ② The similar changing process of the abnormal changes before and after such above M_S7.0 level large earthquakes undergo three stages as "before earthquake-shock time-after earthquake" with the time span of more than 12 months, the "before earthquake" stage and the "after earthquake" stage are more obvious, and the " shock time" stage is relatively stable; ③ The abnormal changes before and after such above M_S7.0 level large earthquake are distributed along the main tectonic belt, and the amplitude of this abnormal changes decreases with the increases of the epicentral distances.