This article presents a method for reducing the computation time required for estimating cumulative sound exposure levels. Sound propagation has to be computed from every source position to every desired receiver location; so if there are many source positions, then the problem can quickly become computationally expensive. The authors' solution to this problem is to extract all possible source-receiver pathways and to cluster these with a self-organizing neural net. Sound propagation is modeled only for the cluster centroids and extrapolated for the entire geographic region. The tool is illustrated for the example of a marine seismic survey over a tropical coral reef. Resident fish species were expected not to flee the reef, but to stay among the corals for the entire duration of the survey. In such cases, the modeling of cumulative sound exposure levels is sometimes requested as part of environmental impact assessments. The tool developed combines a seismic source model, a near-field sound propagation model, and a far-field sound propagation model. The neural network reduces the computation time by a factor of 55. The cost is an error in modeled received levels of less than 1±3dBre1μPa2s.

1.
Department of the Environment and Water Resources (DEW), EPBC Act Policy Statement 2.1—Interaction between offshore seismic exploration and whales, Australian Government (
2007
).
2.
U.S. Environmental Protection Agency
, “
Small takes of marine mammals incidental to specified activities; seismic surveys in the Beaufort and Chukchi Seas off Alaska
,”
Fed. Regist.
71
,
50027
50045
(
2006
).
3.
E.
McCarthy
,
International Regulation of Underwater Sounds: Establishing Rules and Standards to Address Ocean Noise Pollution
(
Kluwer Academic
,
Boston
,
2004
).
4.
A.
Engås
,
S.
Løkkeborg
,
E.
Ona
, and
A. V.
Soldal
, “
Effects of seismic shooting on local abundance and catch rates of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus)
,”
Can. J. Fish. Aquat. Sci.
53
,
2238
2249
(
1996
).
5.
A.
Engås
and
S.
Løkkeborg
, “
Effects of seismic shooting and vessel-generated noise on fish behavior and catch rates
,”
Bioacoustics
12
,
313
315
(
2002
).
6.
J. R.
Skalski
,
W. H.
Pearson
, and
C. I.
Malme
, “
Effects of sounds from a geophysical survey device on catch-per-unit-effort in a hook-and-line fishery for rockfish (Sebastes ssp.)
,”
Can. J. Fish. Aquat. Sci.
49
,
1357
1365
(
1992
).
7.
A.
Slotte
,
K.
Kansen
,
J.
Dalen
, and
E.
Ona
, “
Acoustic mapping of pelagic fish distribution and abundance in relation to a seismic shooting area off the Norwegian west coast
,”
Fish. Res.
67
,
143
150
(
2004
).
8.
A. N.
Popper
,
M. E.
Smith
,
P. A.
Cott
,
B. W.
Hanna
,
A. O.
MacGillivray
,
M. E.
Austin
, and
D. A.
Mann
, “
Effects of exposure to seismic airgun use on hearing of three fish species
,”
J. Acoust. Soc. Am.
117
,
3958
3971
(
2005
).
9.
C. S.
Wardle
,
T. J.
Carter
,
G. G.
Urquhart
,
A. D. F.
Johnstone
,
A. M.
Ziolkowski
,
G.
Hampson
, and
D.
Mackie
, “
Effects of seismic air guns on marine fish
,”
Cont. Shelf Res.
21
,
1005
1027
(
2001
).
10.
J. P.
Carricart-Ganivet
,
J. M.
Lough
, and
D. J.
Barnes
, “
Growth and luminescence characteristics in skeletons of massive Porites from a depth gradient in the central Great Barrier Reef
,”
J. Exp. Mar. Biol. Ecol.
351
,
27
36
(
2007
).
11.
T. F.
Cooper
,
S.
Uthicke
,
C.
Humpfhrey
, and
K. E.
Fabricius
, “
Gradients in water column nutrients, sediment parameters, irradiance and coral reef development in the Whitsunday Region, central Great Barrier Reef
,”
Estuarine Coastal Shelf Sci.
74
,
458
470
(
2007
).
12.
A. N.
Popper
, “
Effects of anthropogenic sound on fishes
,”
Fisheries
28
,
24
31
(
2003
).
13.
M. C.
Hastings
and
A. N.
Popper
, “
Effects of sound on fish
,” California Department of Transportation, Contract. No. 43A0139,
2005
.
14.
J. T.
Yelverton
,
D. R.
Richmond
,
W.
Hicks
,
K.
Saunders
, and
E. R.
Fletcher
, “
The relationship between fish size and their response to underwater blast
,” Report No. DNA 3677T, Defense Nuclear Agency, Washington, DC,
1975
.
15.
J. H.
Stuhmiller
,
K. H. H.
Ho
,
M. J.
Vander Vorst
,
K. T.
Dodd
,
T.
Fitzpatrick
, and
M.
Mayorga
, “
A model of blast overpressure injury to the lung
,”
J. Biomech.
29
,
227
234
(
1996
).
16.
R. D.
McCauley
,
J.
Fewtrell
, and
A. N.
Popper
, “
High intensity anthropogenic sound damages fish ears
,”
J. Acoust. Soc. Am.
113
,
638
642
(
2003
).
17.
J. J.
Govoni
,
L. R.
Settle
, and
M. A.
West
, “
Trauma to juvenile pinfish and spot inflicted by submarine detonations
,”
J. Aquat. Anim. Health
15
,
111
119
(
2003
).
18.
P. C.
Etter
,
Underwater Acoustic Modeling and Simulation
, 3rd ed. (
Spon
,
London
,
2003
).
19.
R. D.
McCauley
,
A. J.
Duncan
,
J.
Fewtrell
,
C.
Jenner
,
M.
Jenner
,
J. D.
Penrose
,
R. I. T.
Prince
,
A.
Adhitya
,
J.
Murdoch
, and
K.
McCabe
, “
Marine seismic survey analysis and propagation of air-gun signals; and effects of air-gun exposure on humpback whales, sea turtles, fishes and squid
,”
Environmental Implications of Offshore Oil and Gas Development in Australia: Further Research
(
Australian Petroleum Production and Exploration Association
,
Canberra
,
2003
), pp.
364
370
,
381
385
, and
498
521
.
20.
ERT (Scotland) Ltd., “
Third strategic environmental assessment for oil and gas activity in Ireland’s offshore Atlantic waters: IOSEA3 Rockall Basin—Environmental report
,” submitted to the Department of Communications, Energy and Natural Resources Ireland (2003), available from http://www.dcenr.gov.ie/Natural/Petroleum+Affairs+Division/Irish+Offshore+Strategic+Environmental+Assessment+%28IOSEA+3%29/ (Last viewed January,
2009
).
21.
Y. V.
Gilchrest
,
T. N.
Fetherston
, and
B. E.
Neales
, “
Analysis of acoustic exposures on marine mammals for the proposed undersea warfare training range
,” NUWC Technical Report, Project No. C744088 (2008), available from http://projects.earthtech.com/uswtr/Library_index.htm (Last viewed January,
2009
).
22.
A. O.
MacGillivray
, “
An acoustic modeling study of seismic airgun noise in Queen Charlotte basin
,” MS thesis,
University of Victoria
, BC, Canada (
2006
).
23.
A.
Ziolkowski
, “
A Method for Calculating the Output Pressure Waveform from an Air Gun
,”
Geophys. J. R. Astron. Soc.
21
,
137
161
(
1970
).
24.
W. H.
Dragoset
, “
A comprehensive method for evaluating the design of airguns and airgun arrays
,” in
16th Annual Proceedings of the Offshore Technology Conference
(
1984
), Vol.
3
, pp.
75
84
.
25.
M.
Laws
,
L.
Hatton
, and
M.
Haartsen
, “
Computer modeling of clustered airguns
,”
First Break
8
,
331
338
(
1990
).
26.
M.
Landro
, “
Modeling of GI gun signatures
,”
Geophys. Prospect.
40
,
721
747
(
1992
).
27.
E. L.
Hamilton
, “
Geoacoustic modeling of the sea floor
,”
J. Acoust. Soc. Am.
68
,
1313
1340
(
1980
).
28.
P.
Kearey
,
M.
Brooks
, and
I.
Hill
,
An Introduction to Geophysical Exploration
(
Blackwell Scientific
,
Oxford
,
2002
).
29.
N.
Barton
,
Rock Quality, Seismic Velocity, Attenuation and Anisotropy
(
Taylor & Francis
,
London
,
2006
).
30.
H. G.
Brandes
,
A. J.
Silva
, and
D. J.
Walter
, “
Geo-acoustic characterization of calcareous seabed in the Florida Keys
,”
Mar. Geol.
182
,
77
102
(
2002
).
31.
Y.
Matsukura
,
A.
Maekado
,
H.
Aoki
,
T.
Kogure
, and
Y.
Kitano
, “
Surface lowering rates of uplifted limestone terraces estimated from the height of pedestals on a subtropical island of Japan
,”
Earth Surf. Processes Landforms
32
,
1110
1115
(
2007
).
32.
S. S.
Fu
,
C.
Tao
,
M.
Prasad
,
R. H.
Wilkens
, and
L. N.
Frazer
, “
Acoustic properties of coral sands, Waikiki, Hawaii
,”
J. Acoust. Soc. Am.
115
,
2013
2020
(
2004
).
33.
J.
Bowlin
,
J.
Spiesberger
,
T.
Duda
, and
L.
Freitag
, “
Ocean acoustical ray-tracing software RAY
,” Technical Report No. WHOI-93-0, Woods Hole Oceanographic Institution, Woods Hole, MA,
1992
.
34.
C.
Erbe
and
D. M.
Farmer
, “
A software model to estimate zones of impact on marine mammals around anthropogenic noise
,”
J. Acoust. Soc. Am.
108
,
1327
1331
(
2000
).
35.
L. M.
Brekhovskikh
,
Waves in Layered Media
(
Academic
,
New York
,
1960
).
36.
M. D.
Collins
,
R. J.
Cederberg
,
D. B.
King
, and
S. A.
Chin-Bing
, “
Comparison of algorithms for solving parabolic wave equations
,”
J. Acoust. Soc. Am.
100
,
178
182
(
1996
).
37.
M. D.
Collins
, “
A split-step Padé solution for the parabolic equation method
,”
J. Acoust. Soc. Am.
93
,
1736
1742
(
1993
).
38.
M. D.
Collins
, “
The stabilized self-starter
,”
J. Acoust. Soc. Am.
106
,
1724
1726
(
1999
).
39.
Z. Y.
Zhang
and
C. T.
Tindle
, “
Improved equivalent fluid approximations for a low shear speed ocean bottom
,”
J. Acoust. Soc. Am.
98
,
3391
3396
(
1995
).
40.
J.
Vesanto
,
J.
Himberg
,
E.
Alhoniemi
, and
J.
Parhankangas
, “
SOM toolbox for Matlab 5
,” Report No. A57, SOM Toolbox Team, Helsinki University of Technology, PO Box 5400, FIN-02015 Hut, Finland, April
2000
.
41.
J.
Vesanto
,
J.
Himberg
,
E.
Alhoniemi
, and
J.
Parhankangas
, “
Self-organizing map in Matlab: The SOM toolbox
,” in
Proceedings of the Matlab DSP Conference
, Espoo, Finland (
1999
), pp.
35
40
.
42.
J.
Vesanto
and
E.
Alhoniemi
, “
Clustering of the self-organizing map
,”
IEEE Trans. Neural Netw.
11
,
586
600
(
2000
).
43.
X.
Lurton
,
An Introduction to Underwater Acoustics: Principles and Applications
(
Springer
,
Berlin
,
2002
).
44.
M. D.
Collins
, “
New and improved parabolic equation models
,”
J. Acoust. Soc. Am.
104
,
1808
(
1998
).
45.
H.
Medwin
and
C. S.
Clay
,
Fundamentals of Acoustical Oceanography
(
Academic
,
Boston
,
1998
).
46.
M. E.
Smith
,
A. S.
Kane
, and
A. N.
Popper
, “
Acoustical stress and hearing sensitivity in fishes: Does the linear threshold shift hypothesis hold water?
,”
J. Exp. Biol.
207
,
3591
3602
(
2004
).
47.
A. N.
Popper
, “
Effects of mid- and high-frequency sonars on fish
,” NUWC Technical Report, Contract N66604-07M-6056, available from http://projects.earthtech.com/uswtr/Library_index.htm (Last viewed January,
2009
).
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