ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

1aPA6. A powerful acoustical source for seismology.

Andrey V. Lebedev

Alexander M. Sutin

Hydroacoustic Div., Inst. Appl. Phys., Russian Acad. Sci., 46 Ulyanov str., Nizhny Novgorod 603600, Russia

To get information about the ``entrails'' of the Earth it is necessary to have a powerful source of seismic waves. Standard equipment for this purpose is too heavy and rather unstable. In this work the possibility of powerful electrodynamic hydroacoustic transducer usage for seismology is investigated theoretically. To match the transducer with earth, a tube containing water is used. The hydroacoustical transducer is placed inside the tube. This transducer produces waves that are transformed to seismic waves. The open end of the tube is a monopole-type source of primary compression waves. This source is a resonant one, and, according to calculations, the Q factor is of the order 10. Working resonance frequency of this system is defined by h(approximately equal to)(lambda)[inf 0]/2 condition, where h is the height of the tube, and (lambda)[inf 0] is the wavelength of sound waves in water filling the tube. Such design of the source permits the exclusion of Rayleigh wave generation which is very important for volume tomography of the Earth. Varying the height of the water column can easily tune the frequency of radiation.