Hydroacoustic waves measured during the 2012 Negros-Cebu earthquake

During the earthquake that occurred on February 6, 2012, between the Negros and Cebu islands (Philippines), a scuba diver who was about 12 km from the epicenter zone, in about 10 m water depth, was taking audio and video recordings using a GoPro camera. The recorded audio reveals a specific spectral signature few seconds after the earthquake occurrence that appears to be related to hydroacoustic waves. Numerical reproduction of the phenomenon produced waves exhibit a frequency spectrum similar to that recorded. Several previous researches, based on theoretical and/or numerical approaches, indicate that hydroacoustic waves are tsunami precursors and can significantly improve the Tsunami Early Warning System. Currently, such pressure waves generated by submarine earthquakes are seldom measured. Therefore, the records presented in this paper can enhance the research on the in situ data analysis.