中文摘要：

大地电磁测深法（Magnetotelluric，MT）是利用空间中分布广泛，频率范围很宽（10^-4～10^4Hz）的天然交变电磁场进行测量的一种频率域电磁测深法。其所直接测量的天然大地电磁场具有结构复杂性，随时间空间变化的多变性，所以研究大地电磁场的成因，组成及变化对提高大地电磁测深法的精度具有重要意义。本文通过对2009年7月22日日全食期间在武汉近郊采集的MT数据来分析研究日食效应对大地电磁场的影响，其特征表现为：①大地电磁场振幅极小值出现在食甚前约2h。②日食期间大地电磁场振幅与变化幅度都会减弱。③日食活动主要影响4～0．1Hz范围内的电磁波。

英文摘要：

Magnetotelluric sounding method （MT） is a method of frequency domain electro- magnetic sounding. It is using the wide frequency range （10^-4- 10^4Hz） of the natural alternating electromagnetic field which is widely distributed in the space. Its direct measurement of the natural magnetotelluric field has the features with the complicated structure, and with the changes in time and space Variability. Therefore, it has great significance for improving the precision of the magnetotelluric sounding method when studying the causes, the change and the composition of magnetotelluric field. This paper analyzes the effect that the total solar eclipse has on the electromagnetic field by collecting the MT data in the out- skirts of Wuhan city by July 22, 2009. Its characteristics are as follows： （1）The minimum field amplitude of the magnetotelluric appeared 2 hours before the eclipse minimum. （2）During the solar eclipse, the field amplitude and the variations of the magnetotelluric field will be weakened. 3. Eclipse activities mainly influence the electromagnetic wave within the framework of the 4-0. 1 Hz.