Analysis of long-range propagation of acoustic waves generated by different types of impulsive sources

CINQUINI, M.; BOS, P.; PRARIO, I.; BLANC, S.; MARQUES ROJO, R.

Viena

Conferencia; Science and Technology Conference; 2021

CTBTO (Comprehensive Nuclear-Test-Ban Treaty Organization)

Offshore seismic surveys with airgun array sources are currently wide spread in all the oceans. They constitute one of the most powerful and systematic impulsive noise sources in marine environments. The sound pulses from large airgun arrays generate signals that contain sufficient energy in the 5-60 Hz band to propagate ocean-basin scales at ranges of hundreds to thousands of kilometres. Under favourable propagation conditions they can be received at the CTBT IMS hydroacoustic stations (HA) with high signal to noise ratio. Unlike previous work, our focus is neither to study their effects on marine species nor to investigate the stratified sedimentary structure of the seabed, but to evaluate whether these signals can be used to validate theoretical predictions of propagation models. A sample of recorded signals from seismic surveys obtained from the IMS HA historical data is exhaustively analysed through cepstral, spectral and time-based techniques. Then, based on the known characteristics of the energy source spectral density of airgun arrays below 100Hz, as published in the literature, some underwater propagation properties are inferred.