Analysis of the variation characteristic in the lithospheric geomagnetic field before and after earthquakes
地震前后岩石圈磁场变化特征分析

This paper focuses on the geomagnetic field variation produced by lithosphere before and after the Ms=5.7 Jiujiang-Ruichang earthquake and the Ms=8.0 Wenchuan earthquake. According to the three-component survey data after these earthquakes and “2005.0 China Geomagnetic Chart” before the earthquakes, lithospheric geomagnetic field models of the two research regions are established. The relations between the earthquakes and different components of the geomagnetic field are preliminarily researched, by comparing and analyzing the variation characteristics of the geomagnetic field (F, D, I,) in the Jiujiang-Ruichang and Wenchuan region. The results show that two earthquake epicenters are located in the vicinity of declination and inclination zero line. After the earthquakes, different components of the geomagnetic field produce different abnormal changes. There are some obvious changes of the geomagnetic field related with the earthquakes in the vicinity of epicenters, and the changes of two earthquake regions have similar regularity.