METHOD OF DETERMINING AN EARTHQUAKE'S EPICENTRE CO-ORDINATES AND THE MOMENT AT WHICH THE EARTHQUAKE STARTS

摘要

A method is proposed of determining an earthquake's epicentre co-ordinates and the moment at which the earthquake starts. The method involves the following steps: a radio signal in the ultra-longwave band is emitted at K different frequencies from N points in space in the direction of the meridians and the signal is received at M points in space, K, N and M being real numbers, M being 2; the signals received at each of the M points are converted to a signal of a standard frequency; the phase difference between the received signals and the standard frequency signal is measured; and the amount by which those measured differences exceed phases of a given magnitude is calculated. The co-ordinates of the earthquake's epicentre are determined as the co-ordinates of the point of intersection of the transmission-receiving paths at which are recorded, in the correlation interval of the emitted signal, the greatest excesses. The moment at which the earthquake starts is determined using the formula: T = tm + [tm - tn]2 / [(t¿n? - tp) - (tm - tn)], wherein tm is the time corresponding to an m-fold excess over the measured phase difference of given magnitude in a given time interval; m is a real number and m 2, n = m-1, p=n-1, and (tm - tn) (tn - tp).