Nonlinear propagation of laser-generated sound pulses in a granular medium.

Nonlinear propagation of finite amplitude acoustic pulses in a water-saturated granular medium is considered, A laser sound source was used to generate acoustical pulses of amplitude up to 3 MPa and duration of about 1 µs in water. Specific acoustical features of the crust such as nonlinear sound pulse distortion and the frequency dependance of attenuation, varying with the amplitude, are considered. A theoretical interpretation of the results is given. [ABSTRACT FROM AUTHOR]