Preliminary analysis of geophone and tetrahedral array data from the Seabed Characterization Experiment

Abstract

As part of the Seabed Characterization Experiment (SCEx), the University of Rhode Island and Wood Hole Oceanographic Institution deployed the low frequency shear measurement system and the interface Wave Sediment Profiler (iWaSP) system in the New England Mud Patch south of Cape Cod in about 70 meters of water. Multiple sensors were utilized to collect data which include a geosled with a geophone array of four vertically gimbaled geophones and a tetrahedral array of four hydrophones. The iWasp was used for exciting the interface waves. The iWaSP system was deployed from the R/V Sharp and it transmitted 10 seconds chirp signals every one minute between 33 and 200 Hz. The geophone array was approximately 100 m from the iWaSP source. Detection of the chirps from geophone and tetrahedral array signals was challenging due to the presence of noise sources such as ship traffic and environmental noise. Data were explored for the presence of iWaSP chirp signals in the audio and further analyzed using techniques such as matched filtering. The preliminary results and initial hypothesis regarding the wave types corresponding to the multiple arrivals will be presented. [Work supported by Office of Naval Research.]