This work describes the results of processing experimental data during synchronous registration of the crust deformations and oscillations of atmospheric and hydrospheric pressures. It was found that internal marine waves with a frequency range from 5 to 20 min are mainly generated by atmospheric disturbances, whose variations are absolutely identical to those of hydrospheric pressure in the shelf zone of the Sea of Japan.

This paper presents an instrument based on an equal-arm Michelson interferometer and a frequency-stabilized helium-neon laser. It is designed to record hydrosphere pressure variations in the frequency range from 0 (conventionally) to 1000 Hz, with accuracy of 0.24 mPa at sea depths of up to 50 m. The operating range of the instrument can be increased by order of magnitude by improving the registration system speed, and accuracy can be enhanced by using larger diameter membranes and/or their smaller thickness. The paper demonstrates some experimental results obtained on the supersensitive detector of hydrosphere pressure variations, confirming its high performance in the infrasonic and sonic ranges.

The paper presents the results of processing recordings of abnormal signals, which originated during the eruption of Hunga Tonga-Hunga Haʻapai volcano, and were registered by a laser nanobarograph and two laser strainmeters; there were three meters of sea-level variations, located in the Sea of Japan, and twelve meters of sea-level variations, located in the Pacific Ocean. Acoustic-gravity Lamb waves, generated in the atmosphere, caused disturbances of similar periods in the Earth’s crust, which were registered by laser strainmeters. Atmospheric impulse and Lamb waves during their propagation over the Pacific Ocean and the Sea of Japan initiated meteorological tsunamis in their waters, at periods corresponding to the seiches (Eigen oscillations) of registration stations’ location areas. In the records of all sea wave recorders, we did not find signs of a classical tsunami origination, and in the records of laser strainmeters, we did not find signals corresponding to seabed displacements at the point of the volcano explosion that led to the formation of a classical tsunami.

A radiating hydroacoustic system intended to generate harmonic and phase-shifted hydroacoustic signals in the frequency band of 1 Hz with a center frequency in the range of 19−26 Hz is described. The maximum change in the radiator volume may be as large as 0.0123 m³, which corresponds to a radiated acoustic power of 1000 W at a frequency of 20 Hz in the boundless water space. The prospects of using the system for carrying out research are demonstrated via the results of its testing on the shelf of the Sea of Japan.