复杂地形下AMT对薄层探测影响的正反演研究

Forward and Inverse Simulation of Influence of AMT on Thin Layer Detection under Complex Terrain

通过地堑、地垒在1~10^4 Hz频率范围内对薄层响应的二维正演模拟,分析总结了起伏地形下音频大地电磁法TM极化模式对薄层的影响规律,揭示了在复杂山区开展音频大地电磁勘探时野外布置的要点。通过对地堑、地垒等复杂地形下的高低阻薄层进行反演计算,发现地堑、地垒模型下,AMT对于高低阻薄层的探测能力不同。地垒模型下,可以准确地探测高阻薄层的空间位置;地堑模型下可以准确地探测低阻薄层的空间位置。

Through the two-dimensional forward simulation of thin layer response in the 1?10^4 Hz frequency range of graben and horst,this paper analyzes and summarizes the influence law of the TM polarization mode of audio magnetotelluric method on thin layer under undulating terrain,and reveals the main points of field arrangement in the process of audio magnetotelluric exploration in complex mountainous areas.Through the inverse calculation on high and low resistance thin layer under the complex terrain,such as graben and horst,it is found that AMT has different detective ability for high and low resistance thin layer under the model of graben and horst.The spatial location of the high resistivity thin layer can be accurately detected under the horst model and the low resistivity thin layer can be accurately detected under the graben model.