### ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

## 2pUW10. On measuring sediment/Biot properties in shallow water at moderate
to high frequencies.

**Ahmed Abawl
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W. S. Hodgkiss
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**
W. A. Kuperman
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**
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*Scripps Inst. of Oceanogr., Univ. of California San Diego, La Jolla, CA
92093-0701
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*
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**Michael D. Collins
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**
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*Naval Res. Lab., Washington, DC 20375
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*
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A broadband line array is being designed and constructed to study the
acoustics of shallow water in the moderate to high-frequency regime. The
64-element array will consist of nested apertures half-wavelength spaced at 4,
8, and 16 kHz with a total bandwidth of 2--20 kHz. The intention is to study
both the forward and inverse problem, the latter with respect to sediment
properties. The poroelastic parabolic equation [Collins et al., this meeting]
is being used for simulations to (1) aid in the design of the array, (2) study
the forward problem, and (3) investigate the potential observables with respect
to the inverse problem. In particular, it is of great interest as to whether
effects related to the Biot description are observable by measuring waveguide
propagation. The use of the parabolic equation formulation will allow for a
consistent extension to range-dependent environments in a future study. [Work
supported by ONR Code 321OA.]