Hydroacoustic monitoring of the oceans

Abstract

In order to verify compliance with this Treaty, an international Monitoring System based on four technologies, seismology, infrasounds, hydroacoustic, and radionuclides, shall be implemented. Therefore, a network of hydrophones and seismic T-wave stations has been designed and evaluated in terms of detectability and location capability. Hydroacoustic waves generated by an undersea explosion or by oceanic earthquakes are propagating over several thousands of kilometers within an oceanic waveguide called So.F.A.R., channel (sound fixing and ranging) as shown by Ewing and Tolstoy (1950). When they are reaching any continental slope or island they are converted in seismic T-waves which are recorded by seismographs. By using both numerical simulations and experimental analysis, a methodology has developed which allows to better understand and quantify the effects of the source parameters and of the propagation characteristics (specifically on the So.F.A.R. channel and of the continental slope) on the recorded waveforms. The results obtained should be useful to improve the evaluation of detectability and location capability of the future hydroacoustic network and should provide some effective guidance to the site survey process. For that purpose and also to have a better understanding of the source parameters and of the acoustic wave propagation, a methodology has developed using both a numerical simulation and an experimental analysis.