PROBLEM TO BE SOLVED: To minimize the economic loss resulting from an earthquake by predicting the earthquake by surely calculating the hypocentral regions of earthquakes of a specific magnitude or stronger by observing electromagnetic fields at observation stations of a specific number or larger and identifying an electromagnetic field pulse which is an omen of earthquakes. ;SOLUTION: Electromagnetic fields are observed at, at least, four observation stations which are separated from each other by about 100km and respectively provided with sensors 1a-1d and observing instruments 2n-2d. Then the electromagnetic field pulse which is an omen of an earthquake is identified and the hypocentral region of the earthquake is found by calculating the occurring area of the pulse. Namely, an observed pulse having an amplitude of a fixed value or larger is transmitted to a main station and recorded by means of data recorders 3a-3d and the number of pulses having amplitude of a fixed value or larger and frequency distributions of the pulse obtained at each observation station are outputted. When a pulse having an amplitude of a fixed value or larger is received at different observation stations at a fixed time difference or shorter, correlators 4a-4d calculate the degree of correlation and delay time of the pulse. A display device 6 indicates the area which is found to be the hypocentral region of the earthquake by means of a data processor 5 on a map together with thunderbolt information.;COPYRIGHT: (C)1997,JPO
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