Long range acoustic measurements of an undersea volcano

Heaney, K.D.; Campbell, R.L.; Snellen, M.

doi:doi:10.1121/1.4818844

Long range acoustic measurements of an undersea volcano

Title

Long range acoustic measurements of an undersea volcano

Author

Heaney, K.D.
Campbell, R.L.
Snellen, M.

Faculty

Aerospace Engineering

Department

Control & Operations

Date

2013-10-01

Abstract

A seamount 8?km southeast of Sarigan Island erupted on 29 May 2010 and was visually observed. The recordings on two sets of hydrophones, operated by International Monitoring System (IMS) of the Comprehensive Test Ban Treaty Organization (CTBTO) are analyzed. Each array is a triplet of axial single hydrophones deployed as a 2?km triangle. Measurements of acoustic intensity for the path to the southern triplet are on the order of 6?dB lower than those received on the northern triplet. Temporal cross-correlation beamforming estimation is performed and the estimated arrival angles for the two arrays, 265° and 267° were consistent with the predicted geodesic arrival of 264.6° and 267.8°, respectively. Cross-correlation between single phones on the northern and southern arrays reveals a peak at 266°, with a cross-correlation of 0.1. Nx2D parabolic equation modeling predicts complete blockage due to seamount interaction along the geodesic path. Overprediction of the seamount blockage indicates that the 2D approximation is incorrect, and three-dimensional propagation must be used to explain the observations. This is demonstrated by the computation of the Adiabatic Mode Parabolic Equation Transmission Loss, which predicts a 5–10?dB lower reception at the southern site.

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http://resolver.tudelft.nl/uuid:891e9013-55b1-4946-a137-0ce0d7a38482

DOI

https://doi.org/10.1121/1.4818844

Publisher

American Institute of Physics

Embargo date

2014-04-01

ISSN

0001-4966

Source

https://doi.org/10.1121/1.4818844