Deep sea hydrophone calibration and signal compare with seismometer, DPG on sea floor

The seismic wave is translated to T-wave when earthquakes occur beneath seafloor with a traveling speed of 1500 m/s in the SOFAR channel. The centers of SOFAR channel is roughly at 1000 m water depth (Tolstoy and Ewing, 1950). Many studies have shown that hydrophone can be set up in the SOFAR channel to collect acoustic data for investigating plate movement (Fox and Dziak, 1999), seismisity (Fox et.al, 2001), characteristic of T-wave (Park et.al, 2001), seafloor volcanism (Nicolas, 1989)… and so on. Institute of Earth Sciences of Academia Sinica had organize a team to develop small power broad-band OBS (Yardbird BB) with Taiwan Ocean Research Institute (TORI) and the Institute of Undersea Technology (IUT) of the National Sun Yat-sen University (NSYSU). The team has also development deep sea hydrophone use in OBS. This poster will show the hydrophone calibration method, result and signal comparison with seismometer, differential pressure gauge (DPG) on sea floor.

Keywords: T-wave; Hydrophone; OBS; differential pressure gauge (DPG)

Reference:

Fox, C. G. and R. P. Dziak, Intenal deformation of the Gorda Plate observedb y hydroacoustimc onitoring, J . Geophys Res., 104, 17603-17615, 1999.

Fox, C. G., H. Matsumoto and T.K.Lau, Monitoring Pacific Ocean seismicity from an autonomous hydrophone array. , J . Geophys. Res., 106,4183-4206, 2001.

Nicolas, A., Structures of ophiolites and dynamics of oceanic lithosphere. Dordrecht ; Boston : Kluwer Academic Publishers, 1989.

Park, M., R.I. Odom, and D.J. Soukup (2001). Modal scattering: a key to understanding oceanic T-waves, Geophys. Res. Lett. 28, 3401-3404.

Tolstoy, I. and M. Ewing (1950). The T phase of shallow-focus earthquakes, Bull. Seismol. Soc. Am. 40, 25-51.