SEA FLOOR SOUND SPEED ESTIMATES FROM WIDE ANGLE REFLECTIVITY: SOFTWARE DEVELOPMENT

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Authors
  1. Dodds, D.J.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN);GeoAcoustics Inc, Aurora ONT (CAN)
Abstract
The report develops a technique for estimating the sound speed and density of sea floor sediments by manual inversion of oblique angle acoustic reflectivities. These are measured using an impulsive "boomer" source and a multichannel streamer receiver towed 30-40 m above the sea floor. This seismic system operates in the 0.3-3 kHz frequency range; the maximum source-receiver separation is 90 m. The sea floor is modeled as a plane interface between a liquid and an elastic solid. Reflected amplitudes can be predicted from the densities and elastic constants of the media using a plane wave model, but at low frequencies a spherical wave model (based on numerical integration of a plane wave decomposition of a point source) must be used. A theoretical model of the seismic system is used to account for the frequency dependent directivity of the source and receivers, and to allow calibration of the system by analysis of direct arrivals at the receivers.
Report Number
DREA-CR-91-403 — Contractor Report
Date of publication
15 Jan 1991
Number of Pages
61
DSTKIM No
91-03463
CANDIS No
70654
Format(s):
Electronic Document(PDF)

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