The Relative Excitation of Seismic Surface and Body Waves by Point Sources

Experimental evidence shows that earthquakes can be differentiated from explosions on teleseismic records by their relatively greater amplitude of Rayleigh waves compared with the amplitude of the direct P-wave; in effect the ratio of magnitude estimates mb/Ms, is greater for explosions than for earthquakes. In this paper we have tried to assess the contribution of source mechanism alone to this effect. We have used point dilatation and double-couple sources to represent explosions and earthquakes and derived the amplitudes of the waves generated from such sources in a uniform half space. The results show that source mechanism is an important factor governing the value of mb/Ms.