DELINEATION OF THE FOCAL AREAS OF CHINA'S HISTORICAL MAJOR EARTHQUAKES AND DETERMINATION OF POTENTIAL SEISMIC FOCUSES USING DATA OF MODERN SMALL SHOCKS

Delineation of the focal area of historical major earthquake is important because only when the location and dimensions of the focal area and the strike of the earthquake—triggering structure are definitely known will we be able to carry out calculation on the influence field of major earthquake. At the same time, in order to predict whether a new potential major earthquake is likely to occur again in the historical focal area, we must in the first place know the location and the