关键词: 地形, 正演, 瞬变电磁响应, 异常体

Abstract: The delectability of transient electromagnetic method (TEM) to multiple 3D conductive sheets with valley topography is discussed in detail in the paper. An anomalous body with a resistivity of 10⁶ohm.m is designed to simulate the valley topography. The results of the modeling illustrate that the total anomalous fields are the summation of anomalous fields produced by the valley and the conductive sheets. The delectability of TEM to the conductive sheets buried shallower beneath the receivers is quite good without valley topography and TEM is much more sensitive to anomalies near the source than those far from the source. It is interesting that the total field will enlarge the anomalies fields of those conductive sheets placed in far source when the valley topography exists and, in some sense, this will be helpful for TEM to detect the anomalies from far source. The delectability of TEM will become weaker when the distance between two anomalous bodies is too small. In general, the delectability of TEM to multiple 3D conductive sheets is still good when valley topography exists.

Key words: topography, forward modeling, transient electromagnetic responses, anomalous bodies