ASA 127th Meeting M.I.T. 1994 June 6-10

2aPA4. On the influence of ground porosity on acoustic/seismic coupling spectra.

Shahram Taherzadeh

Keith Attenborough

Eng. Mech. Discipline, Faculty of Technol., The Open Univ., Milton Keynes MK7 6AA, England

An airborne sound wave striking the ground surface can produce seismic excitation in the ground. The acoustic-to-seismic coupling spectra show distinctive structure. The structure is mainly attributed to wave resonances within the ground layers. This phenomenon has been studied extensively in the past. Here the extent to which certain parameters influence the position of maxima of acoustic-to-seismic coupling are investigated. The ground has been modeled as a vertically layered porous-elastic medium using the modified Biot--Stoll theory. Predictions based on this theory and also some previously derived expressions are compared with data. It is shown that for some typical ground types, only the full Biot--Stoll theory rather than a low velocity elastic layer model is required to predict the acoustic-to-seismic coupling spectra adequately.