Seismic Surveys Impact on Fish and Fisheries.pdf
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Fish / seismic
Page 1
Seismic survey impact on fish, report, dated March 31,2003
Report for
Norwegian Oil Industry Association (OLF):
Seismic Surveys Impact on
Fish and Fisheries
by
Ingebret Gausland
Stavanger, March 2003
Page 2
Seismic survey impact on fish, report, dated March 31,2003
Page
2
1 SUMMARY............................................................................................................ 4
2 SEISMIC SURVEYS.............................................................................................. 5
2.1
Introduction:................................................................................................................... 5
2.2
Operational characteristics ........................................................................................... 6
2.2.1
2-D surveys .............................................................................................................. 6
2.2.2
3-D surveys .............................................................................................................. 7
2.3
The seismic equipment: ................................................................................................. 8
2.3.1
The seismic vessel:................................................................................................... 8
2.3.2
Seismic sources ........................................................................................................ 9
2.3.2.1 Airguns............................................................................................................... 10
2.3.2.2 Waterguns........................................................................................................... 12
2.3.2.3 Marine vibrators................................................................................................. 14
2.3.3
The hydrophone cable............................................................................................ 15
3
FUNDAMENTALS OF UNDERWATER SOUND............................................... 15
3.1
Sound waves.................................................................................................................. 15
3.2
Sound levels................................................................................................................... 17
3.2.1
Intensity.................................................................................................................. 17
3.2.2
Pressure .................................................................................................................. 17
3.2.3
Acoustic Impedance............................................................................................... 18
3.2.4
Attenuation Factors ................................................................................................ 19
3.2.4.1 Geometrical spreading........................................................................................ 19
3.2.4.2 Transmission/Reflection..................................................................................... 19
3.2.4.3 Absorption.......................................................................................................... 19
3.2.4.4 Scattering............................................................................................................ 19
3.2.5
Characteristic differences between air and water................................................... 20
3.3
Measurements of sound............................................................................................... 20
3.3.1
The dB scale........................................................................................................... 21
3.3.1.1 Reference levels .........................................................................
Seismic survey impact on fish, report, dated March 31,2003
Report for
Norwegian Oil Industry Association (OLF):
Seismic Surveys Impact on
Fish and Fisheries
by
Ingebret Gausland
Stavanger, March 2003
Page 2
Seismic survey impact on fish, report, dated March 31,2003
Page
2
1 SUMMARY............................................................................................................ 4
2 SEISMIC SURVEYS.............................................................................................. 5
2.1
Introduction:................................................................................................................... 5
2.2
Operational characteristics ........................................................................................... 6
2.2.1
2-D surveys .............................................................................................................. 6
2.2.2
3-D surveys .............................................................................................................. 7
2.3
The seismic equipment: ................................................................................................. 8
2.3.1
The seismic vessel:................................................................................................... 8
2.3.2
Seismic sources ........................................................................................................ 9
2.3.2.1 Airguns............................................................................................................... 10
2.3.2.2 Waterguns........................................................................................................... 12
2.3.2.3 Marine vibrators................................................................................................. 14
2.3.3
The hydrophone cable............................................................................................ 15
3
FUNDAMENTALS OF UNDERWATER SOUND............................................... 15
3.1
Sound waves.................................................................................................................. 15
3.2
Sound levels................................................................................................................... 17
3.2.1
Intensity.................................................................................................................. 17
3.2.2
Pressure .................................................................................................................. 17
3.2.3
Acoustic Impedance............................................................................................... 18
3.2.4
Attenuation Factors ................................................................................................ 19
3.2.4.1 Geometrical spreading........................................................................................ 19
3.2.4.2 Transmission/Reflection..................................................................................... 19
3.2.4.3 Absorption.......................................................................................................... 19
3.2.4.4 Scattering............................................................................................................ 19
3.2.5
Characteristic differences between air and water................................................... 20
3.3
Measurements of sound............................................................................................... 20
3.3.1
The dB scale........................................................................................................... 21
3.3.1.1 Reference levels .........................................................................
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All languages:English Chinese (Simplified) Chinese (Traditional)
Disclaimer:isheu.com aims to provide an online platform for sharing data, not to infringe the intellectual property rights; if you found the file uploaded by users infringe intellectual property rights, please notify us via Email, we will deal with in a timely manner.
