Q FOR SHORT-PERIOD P-WAVES - IS IT FREQUENCY-DEPENDENT - COMMENT

Douglas (1992) has presented evidence based on deconvolution analyses of British array data recorded from explosions at the Shagan River Tes t Site (STS), USSR and the Nevada Test Site (NTS), USA from which he h as concluded that the source time dependence characteristics of explos ions at these test sites is significantly different from that associat ed with the Mueller-Murphy (M-M) seismic source model. The objective o f this note is to demonstrate that the M-M model is in fact consistent with a very large variety of short-period P-wave observations from ex plosions and to argue that the alternate source time function proposed by Douglas (1992) is inconsistent with both theoretical and observati onal constraints on the explosion source process. More specifically, n etwork-averaged teleseismic P-wave spectra corresponding to NTS, Frenc h Sahara and STS explosions in granite are used to illustrate the fact that the M-M source model can provide remarkably good descriptions of the observed amplitude levels and spectral shapes over the short-peri od band extending from at least 0.5 to 2.5 Hz, as well as seismic esti mates of explosion yield which agree very closely with corresponding y ield estimates obtained from other, independent sources.