地震台站地电场异常特性: 以中国航空工业总公司625研究所为例

通过分析中国航空工业总公司625研究所地电场监测站30多年监测的原始资料, 提取了其中8组数据, 包括4组地电场中的长期异常信号和4组对应震级M_s6.0以上的地震震前短临异常信号.发现这些异常信号有以下特征: 地电场中的长期监测图中包括了许多不同大小、距离远近地震的孕震信息, 其中近区大震会主控一条或多条曲线的走势, 远大、近小的地震会造成曲线时上时下的振荡; 从4组地电场短临信号监测图中发现震前地电场异常总体表现为下降(上升)—折返—回跳—发震的模式, 说明地电场异常变化形态具有相似性和重复性, 证明地电场观测确实能监测到震前异常.发现适合该监测站预测发震时间的新方法: 根据折返天数与回跳天数大致相等, 即回跳日期加上折返天数为发震日期, 证明地电场短临预测方法具有一定的实用性. 

Precursory Abnormal Characteristics of Geoelectric Field:A Case Study of Seismostation in 625 Research Institute of Aviation Industry Corporation of China

The geoelectric field data recorded for more than thirty years at seismostation in 625 Research Institute of Aviation Industry Corporation of China were analyzed, and eight sets of data including four sets of long-term abnormal signals and four sets of short-term abnormal signals were extracted. The abnormal short-term signals correspond to four M_s > 6.0 earthquakes. The geoelectric field signals have the following characteristics. (1) The long-term geoelectric field curves include precursory information from many earthquakes with different magnitudes and epicenter distances. The near-field and major earthquakes control the trendy of geoelectric field curves. Meanwhile big far earthquakes and small near earthquakes can cause oscillations up and down. (2) In the four short-term signals, we find that the geoelectric field curves show a common pattern of up(down), return, bound and occuring phases. The geoelectric field abnormal forms have similarity and repeatability. This proves that the geoelectric field observation can monitor the impending earthquake precursor. A new method to predict the occurrence-time is found. Based on the number of return days approximately be equal to the number of bound days, the date of occurrence time is the date of return plus the number of bound days. It pushes further the method of geoelectric field short-term earthquake precursor toward practice.