METHODS OF MARINE IMPEDANCE FREQUENCY SOUNDING AND MARINE AUDIO-MAGNETOTELLURIC SOUNDING AND COMPLEXES FOR THEIR IMPLEMENTATION Russian patent published in 2024 - IPC G01V3/08 

FIELD: geophysics.

SUBSTANCE: inventions relate to geophysics, namely to devices and methods of low-frequency electromagnetic (EM) sounding of the earth using active (controlled) and natural sources of EM fields, and can be used, in particular, when searching for ore minerals, as well as oil and gas on the sea shelf. In the method of marine impedance frequency probing, bottom impedance is determined in a given area of the water area by determining horizontal orthogonal vectors of electric and magnetic fields from the controlled source. In the marine audio-magnetotelluric sounding method, bottom impedance is determined in a given area of the water area by determining horizontal orthogonal vectors of electric and magnetic fields from a natural source. Each method employs a single autonomous bottom MT-AMT station and (k – 1) pairs of electrodes in measuring streamers located at the bottom of the water area. Sea depth and vertical profile of conductivity of sea water are measured in locations of bottom MT-AMT station and measuring streamers, as well as coordinates of these points. Magnetic field is calculated on sea surface above bottom MT-AMT station. Magnetic field distribution on the sea surface above each pair of electrodes is obtained. Electric field distribution is measured at the bottom along the streamer. Two-point boundary value problem of determining the bottom magnetic field is converted to a Cauchy problem and the magnetic field distribution at the bottom is calculated at the locations of each pair of electrodes.

EFFECT: reduction of labour intensity of marine works and reduction of used equipment.

8 cl, 3 dwg