吉林四平、榆树台地电场与长春台地磁场、分量应变的变化分析

对四平台、榆树台地电场北分量Ex和东分量Ey不同时段分钟值与长春台分量地磁、分量应变资料进行日变形态、日变幅等方面的对比分析，运用FFT将各观测资料的优势周期分解出来，以期进一步得到各物理量之间的相互关系，同时对地电场在地震前的对应性进行相关总结。结果表明：1）两台地电场日变化都以双峰单谷为主；两测向优势周期都是以12 h、8 h为主。与分量磁场相比，东分量By与Ex比较吻合，北分量Bx与Ey的对应性很高；与分量应变相比，12 h的优势周期为共有周期。2）两台地电场都能够记录到明显的地电暴同步变化。3）Ey与Bx的日变幅比较同步，Ex与By的日变幅比较同步，且呈现出较明显的季节变化。4）两台地电场都能够较为清晰地记录到一定的短临异常，但两台震前异常表现形式不尽相同，出现异常的时间也不同：震中距越近，出现异常越早，异常幅度也越大。

Analysis of Geoelectric Field at Siping and Yushu Station,Geomagnetic Field and Strain Component at Changchun Station of Jilin Province

By comparing minute value of the geoelectric fields Ex and Ey at different times at Siping and Yushu stations with the geomagnetic and strain components of Changchun station, this article analyzes the relations of all physical quantities by further calculating their dominant period with FFT. The results demonstrate that: firstly, daily variation of the geoelectric fields at the two stations present double peaks and one valley, and the dominant period of NS and EW trending is 12 h, 8 h. Compared with geomagnetic field, By and Ex have high suitability of fit and Bx and Ey have suitability of fit. The dominant period 12 h is the common period. Secondly, the geoelectric storm recorded has obvious synchronous change. Thirdly, daily variation amplitude between Ey and Bx has a relative synchronous change, as does that between Ex and By. Moreover, it varies obviously with the season. Finally, some short-impending anomalies may be clearly recorded at two stations, but the form and occurrence time of anomaly before earthquakes differ: the nearer the epicentral distance, the earlier occurrence time and the bigger amplitude of anomaly.