Abstract
Assuming that the source time function is a monotonously increasing function with rise time T0, time durations of radiated P and S waves, Tp and Ts, from propagating faults were investigated by simple geometrical considerations. The main results are as follows:
(1) By examining distribution of Ts-Tp for azimuthal directions, it may be possible to determine which of two P nodal Planes of an earthquake with known mechanism is the fault plane and also be possible to know fault length, rupture velocity and rise time of source function, T0.
(2) For a unilateral moving fault, in order that Ts>Tp for almost all the directions, we must ssume a very high rupture velocity compared with elastic wave velocity.
(3) For a bilateral moving fault, Ts is always larger than Tp in all the directions for any rupture velocity.
(4) When the effect of attenuation is taken into account, S wave pulse is more broadened than P wave pulse and the area where one observes Ts>Tp may be extended vastly.
