Broadband Geoacoustic Inversion from Sparse Data Using Genetic Algorithms

Siderius, Martin; Gerstoft, Peter; Nielsen, Peter L.

doi:10.1142/s0218396x98000107

Cited by 33 publications

(22 citation statements)

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“…Matched field inversion ͑MFI͒ is an effective geoacoustic inversion technique that has been benchmarked with simulated data, [1][2][3][4][5][6][7][8][9][10][11] and applied to extract simple but physically meaningful geoacoustic models for several different experimental environments. [12][13][14][15][16][17][18] Point estimation by optimization algorithms and appraisal analysis based on Bayesian theory are the two major approaches.…”

Section: Introductionmentioning

confidence: 99%

Quantifying the uncertainty of geoacoustic parameter estimates for the New Jersey shelf by inverting air gun data

Jiang

Chapman

Badiey

2007

The Journal of the Acoustical Society of America

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This paper describes geoacoustic inversion of low frequency air gun data acquired during an experiment on the New Jersey shelf. Hybrid optimization and Bayesian inversion techniques based on matched field processing were applied to multiple shots from three air gun data sets recorded by a vertical line array in a long-range shallow water geometry. For the Bayesian inversions, full data error covariance matrix was estimated from a set of consecutive shots that had high temporal coherence and small spatial variation in source position. The effect of different data error information on the geoacoustic parameter uncertainty estimates was investigated by using the full data error covariance matrix, a diagonalized version of the full error covariance, and a diagonal matrix with identical variances. The comparison demonstrated that inversion using the full data error information provided the most reliable parameter uncertainty estimates. The inversions were highly sensitive to the near sea floor geoacoustic parameters, including sediment attenuation, of a simple single-layer geoacoustic model. The estimated parameter values of the model were consistent with depth averaged values (over wavelength scales) of a high resolution geoacoustic model developed from extensive ground truth information. The interpretation of the frequency dependence of the estimated attenuation is also discussed.

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Section: Introductionmentioning

confidence: 99%

Quantifying the uncertainty of geoacoustic parameter estimates for the New Jersey shelf by inverting air gun data

Jiang

Chapman

Badiey

2007

The Journal of the Acoustical Society of America

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“…Justification for the single sediment layer assumption is obtained from literature. 12 Here it was found that inversions of synthetic data, calculated for a multi-layer bottom, and using a two-layer model for the forward calculations, resulted in properties of the two-layer bottom that fitted the properties of the actual multi-layer model reasonably well.…”

Section: The Acoustic Problemmentioning

confidence: 86%

An evaluation of the accuracy of shallow water matched field inversion results

Snellen

Simons

Siderius

et al. 2001

The Journal of the Acoustical Society of America

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In this article the accuracy of geo-acoustic and geometric parameter estimates obtained through matched field inversion (MFI) was assessed. Multi-frequency MFI was applied to multi-tone data (200-600 Hz) received at a 2-km source/receiver range. The acoustic source was fixed and the signals were received at a vertical array. Simultaneously with the acoustic transmissions, a CTD (conductivity, temperature and depth)-chain was towed along the acoustic track. A genetic algorithm was used for the global optimization, whereas a normal mode model was applied for the forward acoustic calculations. Acoustic data received at consecutive times were inverted and the stability of the inverted parameters was determined. Also, the parameter estimates were compared with independent measurements, such as multi-channel seismic surveys (for geo-acoustic parameters). The obtained uncertainty in the inversion results was assumed to have two distinct origins. The first origin is the inversion method itself, since each optimization will come up with some solution close to the exact optimum. Parameter coupling and the fact that some parameters hardly influence the acoustic propagation further contribute to this uncertainty. The second is due to oceanographic variability. Both contributions were evaluated through simulation. The contribution of oceanographic variability was evaluated through synthetic inversions that account for the actual sound speed variations as measured by the towed CTD-chain.

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“…Some justification for the two layer approach can be obtained from olXn S to a geo-acoustic benchmarking workshop case [26,27]. In that benchmark case MFP inversions of simulated data, using a two layer model, reasonably fit tlL properties of a multi-layer bottom in a least-squared sense.…”

Section: The Forward Acoustic Propagationmentioning

confidence: 99%

An environmental assessment in the Strait of Sicily: measurement and analysis techniques for determining bottom and oceanographic properties

Siderius

Snellen

Simons

et al. 2000

IEEE J. Oceanic Eng.

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Executive Summary:In October 1997, the En Verse 97 shallow water acoustic experiments were jointly conducted by SACLANT Centre, TNO-FEL and DERA off the coast of Sicily, Italy. The primary goal of the experiments was to test rapid environmental assessment (REA) techniques for shallow water. Most of the oceanographic REA methods discussed here are well developed and emphasis in this report is on determining the sea-bed properties through inversion of measured acoustic data. To develop an operational system, the REA techniques should be capable of identifying sea-bed characteristics over large shallow water area §. In principle, using a towed source measured on receivers at a fixed location, range dependent bottom properties along a selected track could be estimated. The research presented here describes the first steps in developing such a technique. The En Verse 97 sound sources transmitted over a broad-band of frequencies (90-600 Hz) and the signals were measured on a vertical array of hydrophones. The acoustic data were continuously collected as the range between source and receiving array varied from 0.5-6 km. An extensive seismic survey was conducted along the track providing supporting information about the layered structure of the bottom as well as layer sound speeds. The oceanic conditions were assessed using current meters, satellite remote sensing, wave height measurements and casts for determining conductivity and temperature as a function of water depth. Geo-acoustic inversion results taken at different source/receiver ranges show sea-bed properties consistent with the range dependent features observed in the seismic survey data. Some of the issues addressed in this report are: the feasibility of towed sound source geo-acoustic inversions, applying the method to determine range dependent sea-bed properties, and the dependence of the inversions on frequency band and changing water volume. In October 1997, the EnVerse 97 shallow water acoustic experiments were jointly conducted by SACLANT Centre, TNO-FEL and DERA off the coast of Sicily, Italy. The primary goal of the experiments was to determine the seabed properties through inversion of acoustic data. Using a towed source, the inversion method is tested at different source/receiver separations in an area with a range-dependent bottom. The sources transmitted over a broad-band of frequencies (90-600 Hz) and the signals were measured on a vertical array of hydrophones. The acoustic data were continuously collected as the range between source and receiving array varied from 0.5-6 km. An extensive seismic survey was conducted along the track providing supporting information about the layered structure of the bottom as well as layer sound speeds. The oceanic conditions were assessed using current meters, satellite remote sensing, wave height measurements and casts for determining conductivity and temperature as a function of water depth. Geo-acoustic inversion results taken at different source/receiver ranges show sea-bed properties consistent with the ran...

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Broadband Geoacoustic Inversion from Sparse Data Using Genetic Algorithms

Cited by 33 publications

References 0 publications

Quantifying the uncertainty of geoacoustic parameter estimates for the New Jersey shelf by inverting air gun data

Quantifying the uncertainty of geoacoustic parameter estimates for the New Jersey shelf by inverting air gun data

An evaluation of the accuracy of shallow water matched field inversion results

An environmental assessment in the Strait of Sicily: measurement and analysis techniques for determining bottom and oceanographic properties

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