Numerical Modeling of Hydro-acoustic Waves In Weakly Compressible Fluid

Low-frequency hydro-acoustic waves are precursors of tsunamis. Detection of hydro-acoustic waves generated due to the water column compression triggered by sudden seabed movement, could therefore significantly enhance the efficiency and promptness of tsunami early warning systems (TEWS), given the recent advances in deep-sea measurement technology. This low frequency waves propagate with the speed of sound in water, which is significantly larger than the long wave tsunami celerity. The records of the faster hydro-acoustic waves can cope with the shortening decision time of spreading the alarm and in principle dramatically enhance the accuracy and trustworthiness of TEWS. Several investigations have been carried out in order to reveal the physical characteristics of acoustic waves generated by bottom sudden displacement, clarifying that there exists a relationship between the tsunami-genic source and the hydro-acoustic waves. Recent experimental evidence of the existence of low-frequency elastic waves generated by the seabed motion has been found during the Tokachi-Oki 2003 tsunami event (Nosov & Kolesov, 2007). In addition, during occurrence of Haida Gwaii 2012 earthquake, Ocean Network Canada observatories in the southern side of earthquake zone showed low frequency waves collected b