Unexpected dependence of the late-time transient response on the size and configuration of a tem array

The paper discusses decrease in the decay rate of the TEM response in cases when TEM soundings are performed using central loop arrays with small-sized transmitter loops. This effect is not related to geology and, other things being equal, the more noticeable the smaller the transmitter loop and the more resistive the earth. The effect is not observed when the receiver loop is located outside the transmitter loop. We give examples of the decrease in the TEM response decay rate for sites with different geology. The nature of the effect remains not clear. Further research is needed to gain insight into this phenomenon.