Mechanism of faulting in southern California indicated by seismograms*

For about twenty years it has been known that the first impulse due to the longitudinal waves of an earthquake produces a compression of the in certain areas of the earth's surface, whereas in other extended a rarefaction (dilatation) is observed. The pattern depends on the at the source. A summary of the earlier literature has been given Kawasumi (1937). The purpose of the present paper is to investigate such of compressions and dilatations in local shocks in southern and central and to draw conclusions respecting the mechanism of faulting.