scholarly journals Underwater sound levels in the Canadian Arctic, 2014–2019

2021 ◽  
Vol 168 ◽  
pp. 112437
Author(s):  
William D. Halliday ◽  
David Barclay ◽  
Amanda N. Barkley ◽  
Emmanuelle Cook ◽  
Jackie Dawson ◽  
...  
Keyword(s):  
Canadian Arctic ◽  
Underwater Sound ◽  
Sound Levels

One year of background underwater sound levels in Haro Strait, Puget Sound

2005 ◽  
Vol 117 (4) ◽  
pp. 2577-2578 ◽  
Author(s):  
Val Veirs ◽  
Scott Veirs
Keyword(s):  
Puget Sound ◽  
Underwater Sound ◽  
Sound Levels ◽  
One Year

A Model Based Assessment Of Underwater Sound Levels During A Seismic Source Soft-Start Operation

2010 ◽  
Author(s):  
David Hannay ◽  
Roberto Racca ◽  
Scott Carr ◽  
Mike Jenkerson ◽  
Rodger Melton ◽  
...  
Keyword(s):  
Seismic Source ◽  
Underwater Sound ◽  
Model Based ◽  
Soft Start ◽  
Sound Levels

Prediction and Monitoring of Underwater Sound Levels from the Implosion of a Reinforced Concrete Bridge Pier

2017 ◽  
Vol 2628 (1) ◽  
pp. 47-57
Author(s):  
Paul R. Donavan ◽  
James Reyff ◽  
Carrie Janello
Keyword(s):  
San Francisco ◽  
Peak Pressure ◽  
Underwater Sound ◽  
Surface Reflection ◽  
Sound Exposure ◽  
Reinforced Concrete Bridge ◽  
Sound Levels ◽  
Exposure Levels ◽  
And Performance ◽  
Peak Pressures

After the completion of the new east span of the San Francisco–Oakland Bay Bridge in California, large concrete piers of the old span needed to be demolished. To consider using controlled blasting for this action, hydroacoustic levels were predicted and monitored with regard to specified fish and marine mammal criteria. The metrics included peak pressure and sound exposure levels at distances from 25 to more than 4,000 ft from the pier. For peak pressure, the measured levels were slightly higher than estimated, although for sound exposure levels, the measured levels were somewhat lower than estimated because of the effect of surface reflection. A blast attenuation system consisting of a wide bubble stream was used to minimize the hydroacoustic levels in the water surrounding the pier. The implosion event consisted of 588 individual charge detonations ranging from 35 to 21 lb (15.9 to 9.5 kg/delay) spaced 9 ms apart. Although there were 135 individual detonations of the larger 35-lb charges, the highest peak pressures varied in level by 10 to 15 dB during the course of the implosion. The methods for predicting the levels, measured results, analysis of data, and performance of the blast attenuation system are reviewed.

Prediction of underwater sound levels from rain and wind

2005 ◽  
Vol 117 (6) ◽  
pp. 3555-3565 ◽  
Author(s):  
Barry B. Ma ◽  
Jeffrey A. Nystuen ◽  
Ren-Chieh Lien
Keyword(s):  
Underwater Sound ◽  
Sound Levels

scholarly journals Slower Ship Speed in the Bahamas Due to COVID-19 Produces a Dramatic Reduction in Ocean Sound Levels

2021 ◽  
Vol 8 ◽  
Author(s):  
Charlotte Dunn ◽  
James Theriault ◽  
Leigh Hickmott ◽  
Diane Claridge
Keyword(s):  
Sperm Whale ◽  
Mitigation Measures ◽  
Automatic Identification ◽  
Identification System ◽  
Density Level ◽  
Underwater Sound ◽  
Sperm Whales ◽  
Ship Traffic ◽  
Sound Levels ◽  
Ship Speed

As underwater noise from ship traffic increases, profound effects on the marine environment highlight the need for improved mitigation measures. One measure, reduction in ship speed, has been shown to be one of the key drivers in reducing sound source levels of vessels. In 2017, a study began to assess the impacts of increasing commercial shipping traffic on sperm whales in Northwest Providence Channel, northern Bahamas, an international trade route that primarily serves the southeast US. Ship data were collected from an Automatic Identification System (AIS) station combined with recordings from an acoustic recorder to measure underwater sound levels and to detect the presence of sperm whales. Here we analyze a subset of these data to opportunistically investigate potential changes in ship traffic before and during the COVID-19 pandemic. These data span one calendar year from October 2019 to October 2020. A pre-COVID-19 dataset of 121 days, from a recorder approximately 2 km from the shipping route was compared to a 134-day dataset collected during COVID-19 from the same site, comprising 2900 and 3181 ten-minute recordings, respectively. A dramatic decrease in ocean noise levels concurrent with changes in shipping activity occurred during the pandemic. The mean pre-COVID-19 power density level in the 111–140 Hz 1/3-octave band was 88.81 dB re 1 μPa (range 81.38–100.90) and decreased to 84.27 dB re 1 μPa (range 78.60–99.51) during COVID-19, equating to a 41% reduction in sound pressure levels (SPL). After differences in seasonal changes in wind speed were accounted for, SPL decreased during the pandemic by 3.98 dB (37%). The most notable changes in ship activity were significantly reduced vessel speeds for all ship types and fewer ships using the area during the pandemic. Vessel speed was highly correlated to SPL and the only ship-based variable that predicted SPLs. Despite the opportunistic nature [i.e., not a standard before-after-control-impact (BACI) study], this study provides a unique opportunity to assess the effectiveness of ship traffic management strategies, such as slowing ships down, to mitigate impacts on marine life in the study area, including local sperm whale populations.

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