First motions from seismic sources

摘要: ABSTRACT An application of dynamic dislocation theory gives the elastodynamic radiation resulting from sudden occurrence an earthquake due to faulting. The fault plane is visualized as a geometrical discontinuity across which there exists in either one component strain tensor or displacement vector. It shown that are eight independent models, if unilateral faulting assumed; and argument presented demonstrate likelihood does not exist nature. For bilateral models reduced number five. Of these five, two more likely occur nature than others. One these, model, has first-motion pattern formally identical with double couple unfaulted medium. second, shearstrain isolated force latter type mechanism may deep-focus earthquakes. Another radiation, corresponding single medium, results release shear laminar region.