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

The study of an earthquakes mechanism is usually fìnished bythe determination of a fault piane and the direction of displacementalong it. In many aspects of geodynamics and seismology it wouldbe very important to estimate also the dimensions of a source and cliiefly— the magnitude of the displacement in it.This problem can be reduced to the comparing of fields of sfaticaistress before an earthquake and after it. The difference of energies ofthese two fields depends upon source properties in question; lience it ispossible to determine dimensions of the source and the displacementin it if the forni of the source and the difference of the energies be known.The energy difference can be found from observations on the seismicwaves energy.The idea of such an approach belongs to L. Knopoff. He solved thetwo — dimensionai problem which. deals with the study of very strongearthquakes with long faults. The analogica! three — dimensionaiproblem is considered in this paper; it is necessary for studying of morenumerous weaker earthquakes and investigation of some contiguousproblema.