含激电信息的人工源频率域电磁法正演研究——大功率人工固定源极低频电磁法激电效应预研究

ABSTRACT Base on Dias-model, this paper study the forward modeling to IP response with MT souece and CSAMT source with the author’s program，that is to provide the theoretical basis for extracting the IP information from the far field, near field and transition field in extremely low frequency electromagnetic sounding with artificial strong fixed source signal. The outline of the paper is as follows. Firstly, review the history of the complex-resistivity-model, and analyses the bases for choosing Dias model; meanwhile, effects and responses of each parameter in Dias model are analyses. Afterward, study the forward modeling to 1D layered model with MT source, numerically simulate the IP effects of classic geoelectric objects; Find the clear anomaly and relationship between the peak value of the amplitude anomaly ratio and phase anomaly difference with and without IP parameters to be considered within a frequency range. On the basis of the modeling of MT, Study the CSAMT modeling with a dipole-source, obtain the anomaly responses and the relationship between anomaly and characters of object. Base on the infinite line source, study the 2D IP effect of geoelectric objects with 2D modeling. Calculate the response with different source distance, object depth and different wall rock resistivity systemically. Finally, conclude the viewpoints and give the discussion of the result, and point out the lack of this research also.