Abstract：The paper used the 3D finite-difference program written by Mr. Weiss in American Sandia State Lab to implement the case study on relationship between the feature of 3D horizontal electric-dipole source electromagnetics and spatial distribution of anomalous body (geometric feature and buried depth) and gained following knowledge by numeric forward simulation of models: the electric field strength received at same position increases along with increasing the radius of anomalous body, the existence of resistive bed can increase electric field strength, the larger the anomalous body, the stronger the field strength; the normalized curve of electric field showed that the anomaly resulted from anomalous body is smaller and smaller along with reducing the frequency of emission current, and the resulted anomaly becomes gradual increase along with increasing the radius of anomalous body; the resolution of anomalous body becomes poorer and poorer along with increasing buried depth and gradually reducing the electric field strength when radius of anomalous body unchanged and changing buried depth. The results concluded in the paper provided the basis of knowledge on basic propagating characteristics of MCSEM field and interpretation of MCSEM surveying data.
