AN AUTOMATIC TECHNIQUE FOR PRESENTATION OF COINCIDENT-LOOP, IMPULSE-RESPONSE, TRANSIENT, ELECTROMAGNETIC DATA

Coincident-loop TEM sounding data are often presented by plotting the half-space apparent conductivity as a function of delay time. A new al gorithm generates an improved presentation that plots the apparent con ductivity as a function of depth. The resulting data may be further pr ocessed to sharpen or ''spike'' the smoothly varying apparent-conducti vity/depth curves in an attempt to better represent the rapid changes in conductivity that often exist in the earth. The algorithm described involves an approximation, but is simple, easy to use, and computatio nally efficient. A layered conductivity structure is assumed, so the a lgorithm is best for areas where the geology is approximately horizont al. However, the algorithm can also be used to identify anomalous feat ures that are not infinite horizontal layers. The spiked conductivity models derived from synthetic data are consistent with the original la yered-earth models and show a greater resolution than the apparent-con ductivity/depth curves, and sometimes amplify noise in the data. When data are collected along a profile line, the conductivity/depth inform ation can be converted to a color image. For profile data collected ov er the Elura orebody, the image of the spiked conductivity section sho ws an anomalous feature at the orebody, and the color contrast is more marked than it is on the apparent-conductivity/depth image.