Seabed Geoacoustic Structure at the Meso-Scale
Final rept. 1 Jan 2011-30 Sep 2014
PENNSYLVANIA STATE UNIV STATE COLLEGE APPLIED RESEARCH LAB
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The long term science goals of the project are to understand the nature of the seabed at the geoacoustic meso-scale O100-10 m and determine how these structures impact acoustic propagation, diffuse reverberation, and clutter. Several discoveries were made in the course of the project, notably that a there is a persistent scale, O0.1 m that controls reverberation in a number of shallow water environments, and b clutter can be generated by non-discrete, i.e., smoothly and slowly-varying sediment structures in addition to traditional discrete features, e.g., wrecks. In addition, there were a number of significant advances including development of measurement techniquesprocessing to measure meso-scale geoacoustic variability over tens of km with resolution of 0.1 m7 m in the verticallateral dimension and developing tools to separate frequency-dependent effects so that unbiased estimates of intrinsic attenuation can be made. Even on the mid to outer shelf, substantial lateral variability at the 10 m lateral scale is observed. The underlying processes that lead to that strong variability are not understood at this time.
- Geology, Geochemistry and Mineralogy