On estimation of the displacement in an earthquake source and of source dimensions

The study of an earthquake's mechanism is usually finished by the determination of a fault plane and the direction of displacement along it. In many aspects of geodynamics and seismology it would be very important to estimate also the dimensions of a source and chiefly - the magnitude of the displacement in it. This problem can be reduced to the comparing of fields of statical stress before an earthquake and after it. The difference of energies of these two fields depends upon source properties in question; hence it is possible to determine dimensions of the source and the displacement in it if the form of the source and the difference of the energies be known. The energy difference can be found from observations on the seismic waves energy. The idea of such an approach belongs to L. Knopoff. He solved the two - dimensional problem which deals with the study of very strong earthquakes with long faults. The analogical three – dimensional problem is considered in this paper; it is necessary for studying of more numerous weaker earthquakes and investigation of some contiguous problems.