PROPAGATION OF AN ACOUSTIC PULSE OF FINITE-AMPLITUDE IN A GRANULAR MEDIUM

A study of propagation of a wide-band acoustic signal in a granular me dium is reported. Experimental data on the propagation of pulses with an amplitude up to 3 MPa and characteristic length about 1 mu s throug h a sample of cobalt-manganese nodules are compared with a computer mo del of the process. An anomalous signal absorption in the high-frequen cy range observed with relatively weak sounding pulses is explained un der the assumption of a fractal sample structure on a certain scale, W hen the signal amplitude increases, the absorption assumes a normal po wer form which is evidence of substance structural changes.