Detecting the electromagnetic observation manner which relates to forerunning phenomenon and

摘要

PROBLEM TO BE SOLVED: To efficiently capture an electromagnetic field fluctuation related to precursory phenomenon for predicting a crustal movement such as earthquake, volcanic eruption, ground failure or the like with a satisfactory signal to noise ratio.;SOLUTION: In this electromagnetic field observation method related to precursory phenomenon for detecting an electromagnetic field signal according to a rapid movement in the ground to allow the prediction of the crustal movement, the electromagnetic field fluctuation is measured by capturing a received signal from a coated wire which is to form a lengthy antenna laid on or under the ground of an intended area by a receiving device to detect the abnormality and position of the field intensity. As the coated wire, the feeder of a submarine cable or optical submarine cable is used, and the received signal is captured from one end of the coated wire by the ground receiving device. A pair of parallel wires or a pair of balanced strands is used for at least the ground part of the coated wire, and a submarine earth is mounted on the tip of one core wire through an impedance matching resistor to capture the received signal from both ends of the coated wire by the ground receiving device.;COPYRIGHT: (C)2002,JPO