Том: 2021 , Год издания: 2021

In the near-surface TEM sounding method, it is desirable to measure the transient response starting from the earliest possible time. This requires the current in the transmitter loop to be switched off quickly, which necessitates working with a low transmitter current. In this case, the loop manifests itself as a symmetric combination of two transmission lines, and the current at different points of the loop perimeter is turned off at different times. We present transient electromagnetic responses measured with offset receiving loops, which vary depending on the place where a pulse current source is connected to the transmitter loop. The survey was carried out on the ice cover of Lake Baikal. It has been shown that at early times a delay in turning off the transmitter loop current affects transient voltage induced in offset receiving loops unlike the central loop response, which remains the same,. This fact which should be taken into account when interpreting early-time TEM data.