Underwater Explosions as Acoustic Sources

Weston, D. E.

doi:10.1088/0370-1328/76/2/307

Cited by 90 publications

(47 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Taking a look at each term: 10 log 10 \×(j) 1 2 is the dB power level out of our spectrum program re 1 digital unit, or 1 µV, 10 log 10 C 2 (j) = 20 log 10 CU) is the dB response of the system re µV/ (cm/s), and 10 log 10 (poco2 f} = 10 log 10 [(2.3 g/cm 2 )(3 × 10 5 cm/s)(2)(20.48 s)] The energy-flux-density of the source, (10 log 10 E s ), must be calculated for each source used, or using the method of Weston (1960).…”

Section: U)mentioning

confidence: 99%

OSS IV: Noise Levels, Signal-to-Noise Ratios, and Noise Sources

Duennebier¹,

McCreery²,

Harris³

et al. 1987

Initial Reports of the Deep Sea Drilling Project

View full text Add to dashboard Cite

The ocean sub-bottom seismometer (OSS IV) is one of the quietest seismic stations in the world at frequencies between 4 and 15 Hz. Noise levels of 10 -12 m 2 /Hz are observed above 4 Hz. Noise at frequencies above 5 Hz appears to be caused by system noise during quiet periods, but is dominated by storms at other times. Ships, whales, and earthquakes also add to the noise. The equivalent acoustic noise level varies between 60 and 70 dB re 1 µPa, about 10 to 20 dB quieter than the ocean. Signals generated in the ocean can be observed out to long distances, with propagation loss on the order of 120 dB (referenced to a source level at 1 m) at 100 km. Signals generated from earthquakes are observed about once per hour with signal-to-noise ratios and fidelity considerably improved over those obtained from ocean bottom seismometers. Bottom loss measurements indicate that acoustic signal amplitudes decrease by slightly less than a factor of two with every reflection from the ocean bottom at pre-critical angles.

show abstract

Section: U)mentioning

confidence: 99%

OSS IV: Noise Levels, Signal-to-Noise Ratios, and Noise Sources

Duennebier¹,

McCreery²,

Harris³

et al. 1987

Initial Reports of the Deep Sea Drilling Project

View full text Add to dashboard Cite

show abstract

“…The acoustical properties of explosives are summarised by Weston (1960Weston ( , 1962. The main feature is a short shock wave comprising a sharpalmost instantaneous-rise in pressure followed by an exponential decay with a time constant of a few hundred microseconds.…”

Section: Pressure Measurements Of Large Explosions In Shallow Watermentioning

confidence: 99%

“…The main feature is a short shock wave comprising a sharpalmost instantaneous-rise in pressure followed by an exponential decay with a time constant of a few hundred microseconds. The expanding shock wave creates a large pulsating bubble with successive expansions and contractions that give rise to a series of weaker, more symmetrical bubble pulses as happens also with an airgun pulse (Weston, 1960;Cole, 1965). In shallow water, the multiple interactions of the shock and acoustic waves create a more complex pattern.…”

Section: Pressure Measurements Of Large Explosions In Shallow Watermentioning

confidence: 99%

“…Since there is a lack of acoustic measurements for large explosions (charge mass much larger than 1 kg TNT equivalent) in shallow waters (bottom depths less than 50 m) (Weston, 1960;Chapman, 1985;Soloway & Dahl, 2014), measurements of sound produced by several large underwater explosives in shallow water environments were carried out. These measurements were used to correct deep water source models for explosions and were used in combination with a shallow water propagation model to generate maps of received sound exposure level (SEL) for the reported explosions in 2010 and 2011.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Assessing the Impact of Underwater Clearance of Unexploded Ordnance on Harbour Porpoises (Phocoena phocoena) in the Southern North Sea

Benda-Beckmann

Aarts²,

Sertlek

et al. 2015

Aquat Mamm

View full text Add to dashboard Cite

Large amounts of legacy unexploded ordnance (UXO) are still present in the North Sea. UXO are frequently accidentally encountered by fishermen and dredging vessels. Out of concern for human safety and to avoid damage to equipment and infrastructure from uncontrolled explosions, most reported UXO found in the Dutch Continental Shelf (DCS) are detonated in a controlled way. These underwater detonations produce high amplitude shock waves that may adversely affect marine mammals. The most abundant marine mammal in the DCS is the harbour porpoise (Phocoena phocoena), a species demonstrated to be highly sensitive to sound. Therefore, an assessment of potential impacts of underwater explosions on harbour porpoises was undertaken. Information regarding UXO cleared in the DCS provided by the Netherlands Ministry of Defence was used in a propagation model to produce sound exposure maps. These were combined with estimates of exposure levels predicted to cause hearing loss in harbour porpoises and survey-based models of harbour porpoise seasonal distribution on the DCS. It was estimated that in a 1-y period, the 88 explosions that occurred in the DCS very likely caused 1,280, and possibly up to 5,450, permanent hearing loss events (i.e., instances of a harbour porpoise predicted to have received sufficient sound exposure to cause permanent hearing loss). This study is the first to address the impacts of underwater explosions on the population scale of a marine mammal species. The methodology is applicable to other studies on the effects of underwater explosions on the marine environment.

show abstract

“…The advantages of short pulses as broad band sources with optimum time resolution have lead to the widespread employment of explosive charges, electric sparks, and other impulse generators such as the Edgerton Thumper or Boomer as sonic sources for hydroacoustic measurements (Weston, 1960;Worzel, Ewing, and Pekeris 1948;Hersey, Edgerton, Raymond, and Hayward 1960;Hoskins and Knott, 1961;Knott and Hersey, 1956). The extremely short rise time and exponential decay of at least some parts of the signal emitted by most of these sources lends itself to accurate analysis of very small travel time differences by the use of wide band filtering at medium to high frequencies.…”

mentioning

confidence: 99%

Development of Sound Analysis Equipment for Sonar Research. Part Iii

BAXTER¹,

CHI²

1961

View full text Add to dashboard Cite

Underwater Explosions as Acoustic Sources

Cited by 90 publications

References 10 publications

OSS IV: Noise Levels, Signal-to-Noise Ratios, and Noise Sources

OSS IV: Noise Levels, Signal-to-Noise Ratios, and Noise Sources

Assessing the Impact of Underwater Clearance of Unexploded Ordnance on Harbour Porpoises (Phocoena phocoena) in the Southern North Sea

Development of Sound Analysis Equipment for Sonar Research. Part Iii

Contact Info

Product

Resources

About