Meter-Scale Seafloor Geodetic Measurements Obtained from Repeated Multibeam Sidescan Surveys
2019; Taylor & Francis; Volume: 42; Issue: 6 Linguagem: Inglês
10.1080/01490419.2019.1661887
ISSN1521-060X
AutoresJ. B. DeSanto, David T. Sandwell,
Tópico(s)Seismic Imaging and Inversion Techniques
ResumoWe calibrate a technique to use repeated multibeam sidescan surveys in the deep ocean to recover seafloor displacements greater than a few meters. Displacement measurements from seafloor patches (3 km by 20 km) on the port and starboard side of the ship are used to estimate vertical and across-track displacement. We present displacement measurements from a survey of the Ayu Trough southwest of the Marianas Trench using a 12 kHz multibeam. Vertical and across-track displacement errors for the 12 kHz multibeam sonar are typically 0–2 m with RMS uncertainties of 0.25–0.67 m in the across-track and 0.37–0.75 m in the vertical as determined by 3-way closure tests. The uncertainty of the range-averaged sound velocity is a major error source. We estimate that variations in the sound velocity profile, as quantified using expendable bathythermographs (XBTs) during data collection, contribute up to 0.3 m RMS uncertainty in the across-track direction and 1.6 m RMS uncertainty in the vertical direction.
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