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Kevin Williams

Liaison of SEG & Senior Principal Physicist

Associate Professor, Oceanography






Kevin Williams' research efforts include theoretical and experimental examination of scattering from, and propagation within, ocean sediments. He is also involved in research on the effects of ocean internal waves on acoustic imaging.

Dr. Williams has been with the Laboratory since 1988 and now serves as a principal physicist and the Chair of the Ocean Acoustics Department. He holds a Ph.D. in physics (Washington State University) and the post of Associate Professor in the UW School of Oceanography.

Department Affiliation



B.S. Physics, Washington State University, 1979

M.S. Physics, Washington State University, 1983

Ph.D. Physics, Washington State University, 1985


2000-present and while at APL-UW

Noise background levels and noise event tracking/characterization under the Arctic ice pack: Experiment, data analysis, and modeling

Williams, K.L., M.L. Boyd, A.G. Soloway, E.I. Thorsos, S.G. Kargl, and R.I. Odom, "Noise background levels and noise event tracking/characterization under the Arctic ice pack: Experiment, data analysis, and modeling," IEEE J. Ocean. Eng., 43, 145-159, doi:10.1109/JOE.2017.2677748, 2018.

More Info

1 Jan 2018

In March 2014, an Arctic Line Arrays System (ALAS) was deployed as part of an experiment in the Beaufort Sea (approximate location 72.323 N, 146.490 W). The water depth was greater than 3500 m. The background noise levels in the frequency range from 1 Hz to 25 kHz were measured. The goal was to have a three-dimensional sparse array that would allow determination of the direction of sound sources out to hundreds of kilometers and both direction and range of sound sources out to 1–2 km from the center of the array. ALAS started recording data at 02:12 on March 10, 2014 (UTC). It recorded data nearly continuously at a sample rate of 50 kHz until 11:04 on March 24, 2014. Background noise spectral levels are presented for low and high floe-drift conditions. Tracking/characterization results for ice-cracking events (with signatures typically in the 10–2000-Hz band), including the initiation of an open lead within about 400 m of the array, and one seismic event (with a signature in the 1–40-Hz band) are presented. Results from simple modeling indicate that the signature of a lead formation may be a combination of both previously hypothesized physics and enhanced emissions near the ice plate critical frequency (where the flexural wave speed equals that of the water sound speed). For the seismic event, the T-wave arrival time results indicate that a significant amount of energy coupled to T-wave energy somewhere along the path between the earthquake and ALAS.

Buried targets in layered media: A combined finite element/physical acoustics model and comparison to data on a half buried 2:1 cylinder

Williams, K.L., "Buried targets in layered media: A combined finite element/physical acoustics model and comparison to data on a half buried 2:1 cylinder," J. Acoust. Soc. Am., 140, EL504-EL509, doi:10.1121/1.4971324, 2016.

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1 Dec 2016

Previously, a combined finite element/physical acoustics model for proud targets [K. L. Williams, S. G. Kargl, E. I. Thorsos, D. S. Burnett, J. L. Lopes, M. Zampolli, and P. L. Marston, J. Acoust. Soc. Am. 127, 3356–3371 (2010)] was compared to both higher fidelity finite element models and to experimental data for a proud 2:1 aluminum cylinder. Here that expression is generalized to address the case of a target buried in a layered media. The result is compared to data acquired for the same 2:1 cylinder but half buried in a mud layer that covers the sand sediment (considered here as infinite in extent below the mud layer). The generalized expression reduces to both the previous proud result and to the result for a target buried in an infinite medium under the appropriate limiting conditions. The model/data comparisons shown include both the previous proud model and data results along with the ones for the half buried cylinder. The comparison quantifies the reduction in target strength as a function of frequency in the half buried case relative to the proud case.

Scattering from a finite cylindrical target in a waveguide

Kargl, S.G., T. Shim, K. Williams, and S. Im, "Scattering from a finite cylindrical target in a waveguide," Proc., MTS/IEEE OCEANS Conference, 19-23 September, Monterey, CA, doi:10.1109/OCEANS.2016.7761277 (IEEE, 2016).

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1 Dec 2016

Detection of an object in shallow water has seen a resurgence in importance due to concerns for harbor security. When the horizontal range to an object is large compared to the nominal water depth, then the response of an object to active sonar must necessarily include possible interactions with the boundaries of the waveguide. As an initial step toward the development of detection algorithms, we consider an object in a homogeneous waveguide with planar boundaries. Reflection of the transmitter, receiver, and their images through boundaries allows the scattering problem to be recast into a superposition of many free field scattering problems. An overview of our model and its application to a cylindrical target in littoral waters are given.

More Publications

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center