大地电磁多站叠加系统的分辨率误差分析

使用多站叠加技术将会降低大地电磁响应的分辨率，该分辨率误差是制约大地电磁多站叠加系统发展的主要原因。以Poll的大地电磁仿真算法为基础，建立了一个二度异常体的模型。基于该模型，通过计算机模拟得到了大地电磁的多站叠加结果。将该结果与真实理论值进行对比，可以得到任意测点在不同站间距和不同频段的多站叠加误差值。误差分析表明，只要选择合适的台站间距，多站叠加方法不会明显降低大地电磁理论的分辨率。对于埋深在1 km以内的不均匀体，300 m的台站间距绝对安全。

Resolution error analysis of magnetotelluric multi-station superposition system

The multi-station superposition technology will reduce the resolution of the magnetotelluric(MT) response.The resolution error is the main reason to restrain the development of the MT multi-station system.On the base of Poll’s MT simulation algorithm,the model of two-dimensional anomalous body is constituted.Based on the model,the MT multi-station superposition values are obtained by computer simulation.Through comparing the values with the true values,the MT superposition errors are obtained at any site and all frequencies,in different station spacing.The error analysis shows that the multi-station superposition does not significantly reduce the MT resolution as long as the distance between stations is appropriate.For the inhomogeneous body buried within 1km depth,the 300 m station spacing is absolutely safe.