Method and device for detecting underground transient electromagnetism in grounded source through long wire

The invention relates to a method and a device for detecting underground transient electromagnetism in a grounded source through a long conductor wire; the device comprises a grounded wire as an emission source and an underground receiving device as a receiver; the grounded wire is arranged on the ground; receiving probes are arranged point by point in a hole along the direction of a drill hole or in an underground passage along the direction of the passage by utilizing the original drill hole or the original underground passage; the grounded wire is composed of three groups of grounded wires, wherein the two groups of grounded wires are parallel to each other and simultaneously vertical to the third group of grounded wires. According to the device for detecting the underground transient electromagnetism in the grounded source through the long wire disclosed by the invention, an electric field generated by the grounded wire is intersected with a stratum having different electrical resistivity values; detection of a low-resistance object is easily carried out according to induced current excited by a horizontal component; detection of a high-resistance object is easily carried out according to charge on a stratum electrical interface induced by a vertical component; compared with a large loop, by means of the long wire, the device has better flexibility; and furthermore, the high-resistance object is also detected easily.