Method of imminent earthquake prediction by observation of

Abstract

A seismic electromagnetic field signal is detected at each of observation stations installed at at least two places, and civil noise and atmospheric discharge noise are eliminated from the signal to obtain a low-frequency seismic electromagnetic field signal O.sub.s. A local characteristic signal C.sub.e and a refined local characteristic signal C.sub.f are obtained by processing the signal O.sub.s. The signals O.sub.s, C.sub.e and C.sub.f are transmitted to a central station. At the central station, a delay time T and a half-width H are obtained from the cross-correlation function between the observation stations, and further a regional characteristic signal C.sub.r is obtained from the seismic electromagnetic field signal O.sub.s. An earthquake source region distribution, an earthquake magnitude, and earthquake occurrence time are estimated on the basis of the signals obtained at the central station and the local characteristic signal C.sub.e and refined local characteristic signal C.sub.f obtained at each observation station.