垂直电场观测试验及数据初步分析

Experimental observation and preliminary data analysis of vertical geo-electric field

地震发生前的电磁异常现象已被地面、卫星等多种观测手段观测到.目前,我国已经建成了100多个水平地电场观测台站,然而对于垂直电场的观测仍是一个空白.自2009年4月开始,在甘肃天祝地震前兆科学台阵的红沙湾、黄羊川、松山建立了3个垂直电场观测试验站,进行垂直地电场的试验观测,在我国专门的垂直地电场观测试验研究尚属首次.通过近1年的观测试验,取得了有价值的观测资料.从数据的初步结果来看,垂直电场的日变化形态清晰,黄羊川和松山观测数据的日变幅度在16 mV/km左右,红沙湾观测数据的日变幅度在8 mV/km左右;垂直电场日变化周期的主要成分是24小时的全日波,其次是12小时周期的半日波.

Electromagnetic anomalies before earthquakes have been observed many times on ground and by satellite.At present,there are more than one hundred stations for horizontal geo-electric field observation in China.However,there had been none for vertical geo-electric observation before this study.Since April 2009 we have set up three vertical geo-electric field observation sites at Songshan,Huangyangchuan and Hongshawan in Tianzhu region,Gansu province.It is the first time to do this kind of study in China.For one year’s measurement the vertical geo-electric data display a long-term fluctuation and a strong diurnal variation.The diurnal variation amplitude is about 16 mV/km in Songshan and Huangyangchuan,and 8 mV/km in Hongshawan.By spectrum analysis we found that the amplitude of the 24 h period component is the largest and the 12 h period ones is secondary in vertical geo-electric diurnal variation.