Study of Low-Frequency Hydroacoustic Waves’ Behavior at the Shelf of Decreasing Depth

Abstract

In research into various hydrophysical and hydroacoustic wave processes, it is extremely important to know the regularities of their propagation in the sea at decreasing depths, especially in the shelf areas, and also to know the regularities of their transformation into seismoacoustic processes in the earth crust. In the course of the processing and analysis of the experimental data of our complex experiment, in this paper we investigate these regularities. In our experiment, we used a low-frequency hydroacoustic transmitter that generated harmonic oscillations at the frequency of 22 Hz and received hydroacoustic systems with a shore laser strainmeter. It was established that hydroacoustic waves, propagating at the shelf of decreasing depth, transform into seismoacoustic waves at the depth of the sea equal to or less than a half-length of the hydroacoustic wave. A comparison of the results of this work with earlier-obtained results allows us to state that such regularities should be inherent to all hydrophysical and hydroacoustic processes.

Fluctuations of the Sea Level, Caused by Gravitational and Infra–Gravitational Sea Waves

“…Subsequently, the experimental data were processed according to the set tasks. In the low-frequency sound range (20-1000 Hz), the propagation regularities of hydroacoustic signals, generated, among other things, by low-frequency hydroacoustic emitters, were investigated [14]. In the higher frequency range (1-20 Hz), the formation peculiarities of the microseisms in the "voice of the sea" range were studied [15].…”