Electromagnetic observations by the method of far-field transient electromagnetic sounding are presently carried out in “dipole-dipole” (AB-MN) modification. The “ЭРГУ-600-2” electropulse system is used as a source of electromagnetic field excitation by sending the series of sign-changing 5s pulses to the AB feeder dipole 4.2 km long.

Formation of pulses of bit synchronization and external start-up of “ЭРГУ” by precise time signals received from GPS receiver as well as control and measuring of parameters of current pulses produced by “ЭРГУ” are ensured by “ТИС-2” current station.

Registration and pre-processing of responses to signals sent into the Earth’s crust are carried out by “ИС-2” multi-channel receiving measuring stations developed by RS RAS.

Observations are recorded daily at 6 stationary stations and once a week at each of the 13 field observation sites of the mobile receiving station on the base of “ГАЗ-66” vehicle.

Scheme of electromagnetic sounding points location: the red markers are the stationary points, green markers are the mobile points

Results of long-term observations using far-field transient EM sounding method for each station are stored in the laboratory's database and are usually presented in the form of variation series (graphs) ρ_τ for different times of formation of the field.

Graphs of the apparent electrical resistivity ρ_τ for differently oriented (North-South and West-East) receiving dipoles of Issyk-Ata station, corresponding to different times of formation of the field: 0.14 s and 3.14 s

In 2002-2003, for the purpose of studying the anisotropy of the apparent electrical resistance, observations were made on the territory of polygon at “Almaz” and “Baza” far-field transient EM sounding points with a fan (through 45°) location of the receiving dipoles.