A brief overview of seismic air-gun arrays

Caldwell, Jack; Dragoset, William H.

doi:10.1190/1.1438744

Cited by 88 publications

(70 citation statements)

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“…For the Nordkappbanken experiment, we did not have hydrophone observations and simply used the same source level of 250.5 dB as in the Vesterålen case. Note that no difference in directionality was assumed and that the air-gun configuration was slightly different; based on the data in Table 1 and following Caldwell and Dragoset (2000), we may expect a difference of 1.3 dB re 1 Pa 2 (1 s). Using eq.…”

Section: Simple Noise Propagation Modelmentioning

confidence: 99%

“…Note that Carey (2006) uses the notation E x as opposed to E. Note also that source levels are different than the actual exposure level close to the air-gun (Caldwell and Dragoset 2000), since the signals from the individual air-guns interact and create the combined and focused pulse in the far field. Consequently, the EFSL serves only as a reference when estimating the levels at a distance and are not valid at short range.…”

Section: Simple Noise Propagation Modelmentioning

confidence: 99%

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Evaluating the effect of seismic surveys on fish — the efficacy of different exposure metrics to explain disturbance

Handegard

Tronstad

Hovem

2013

Can. J. Fish. Aquat. Sci.

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Abstract:To assess potential disturbance effects on fish from seismic air-gun surveys, we described several metrics to characterize the exposures from such surveys, including the number of emissions by area and time, and metrics based on accumulated sound exposure levels (SEL). For the SEL-based metrics we used both a simple spherical-geometrical model and a model that incorporated physical sound propagation properties such as bottom topography and the vertical difference in sound speed. We applied the metrics to two experiments in Norwegian waters (the Nordkappbanken and Vesterålen experiments) where fish distributions and fisheries were affected by the air-guns, but where the disturbance was stronger in the Nordkappbanken case. The metrics based on the number of emissions by area and time showed a stronger impact in the Nordkappbanken case. For the SEL-based metrics, the simple sound propagation model failed because of artificially elevated levels close to the emissions, but for the more complex propagation model, contrary to expectations, a stronger SEL was found in the Vesterålen case. We conclude that simple sound propagation models should be avoided and that the reliance on sound energy metrics like SEL for disturbance effects must be interpreted with caution.Résumé : Dans le but d'évaluer les possibles effets que peuvent avoir les échantillonnages sismiques par canons à air, nous décrivons différentes métriques permettant de caractériser l'exposition de telles pratiques d'échantillonnage. Ceci inclut le nombre d'émissions par zones et périodes ainsi que les métriques basées sure les niveaux accumulés d'exposition sonore (SEL). Nous avons utilisés deux modèles distincts de propagation du son. En particulier, le second modèle intègre les propriétés physiques de la propagation du son comme la topographie ou la différence verticale de vitesse du son. Nous avons appliqué les métriques à deux études lors lesquelles les distributions des poissons ainsi que le succès de pêche ont été affectés. Le niveau de perturbation reporté était plus important lors de la première étude. Les métriques basées sur le nombre d'émissions en fonction de la zone et de la période montrent une exposition sonore plus forte lors de la première étude. Pour les métriques basées sur les SEL, si le modèle de propagation simple du son n'apparait pas satisfaisant du fait de niveaux artificiellement élevés proche de la source d'émission, le second modèle de transmission, et ce contrairement à nos attentes, détecte un SEL plus fort lors de la seconde étude. Nous concluons que les modèles de propagation simple du son ne devraient pas être employés et que l'utilisation de métriques tel que le SEL pour des effets de perturbation se doivent d'être interprétés avec précaution.

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Section: Simple Noise Propagation Modelmentioning

confidence: 99%

Section: Simple Noise Propagation Modelmentioning

confidence: 99%

Evaluating the effect of seismic surveys on fish — the efficacy of different exposure metrics to explain disturbance

Handegard

Tronstad

Hovem

2013

Can. J. Fish. Aquat. Sci.

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“…During a typical seismic survey, each airgun fires sharp, broadband, low-frequency bursts of gas every 10 to 30 s towards the seabed (e.g. Greene & Richardson 1988, Dragoset 1990, 2000, Caldwell & Dragoset 2000. In many instances, we found that the time be tween seismic pulses was occupied by a series of multiple arrivals of the same reverberated pulse immediately following the original (Guerra et al 2011(Guerra et al , 2016, thus inundating the soundscape with near-continuous elevated noise levels.…”

Section: Discussionmentioning

confidence: 99%

Widespread spatial and temporal extent of anthropogenic noise across the northeastern Gulf of Mexico shelf ecosystem

Estabrook¹,

Ponirakis²,

Clark³

et al. 2016

Endang. Species. Res.

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“…Acquisition schema with the towed land streamer is similar to technique on which the marine surveys was primarily based [3,4,6,9]. In contrast to the continuous movement of marine survey systems, the operational procedure of the towed land streamer is based on a "excitation technique at a standstill" tactic with some projected acquisition step [17,7,8,14,15].…”

Section: Brief Description Of Device Application Proceduresmentioning

confidence: 99%

“…Researchers for over two decades attempted to find a way to tow long receiver spreads across the ground surface in a way similar to marine sea-streamers. This would allow to transfer efficiency of seismic surveying to land [2], [3], [8] Shear wave land streamers were also developed and tested for near-surface applications during the late 1990s [9]. Land streamers, that towed arrays or spreads, have primarily been designed and tested for applications of so called continuous seismic profiling.…”

Section: Introductionmentioning

confidence: 99%

Geodetic survey as a means of improving fast MASW (Multichannel Analysis Of Surface Waves) profiling in difficult terrain/land conditions

Matuła

Lewińska

2018

E3S Web Conf.

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Abstract. This paper revolves around newly designed and constructed system that can make 2D seismic measurement in natural, subsoil conditions and role of land survey in obtaining accurate results and linking them to 3D surface maps. A new type of land streamer, designed for shallow subsurface exploration is described in this paper. In land seismic data acquisition methods a vehicle tows a line of seismic cable, lying on construction called streamer. The measurements of points and shots are taken while the line is stationary, arbitrary placed on seismic profile. Exposed land streamer consists of 24 innovatory gimballed 10 Hz geophones. It eliminates the need for hand 'planting' of geophones, reducing time and costs. With the use of current survey techniques all data obtained with this instrument are being transferred in to 2D and 3D maps. This process is becoming more automatic.

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A brief overview of seismic air-gun arrays

Abstract: This article summarizes salient points one must know about seismic airgun arrays to discuss seriously how they might affect marine life. It is by no means exhaustive but tries to be thorough enough without being too involved to deter the general reader.

Cited by 88 publications

References 0 publications

Evaluating the effect of seismic surveys on fish — the efficacy of different exposure metrics to explain disturbance

Evaluating the effect of seismic surveys on fish — the efficacy of different exposure metrics to explain disturbance

Widespread spatial and temporal extent of anthropogenic noise across the northeastern Gulf of Mexico shelf ecosystem

Geodetic survey as a means of improving fast MASW (Multichannel Analysis Of Surface Waves) profiling in difficult terrain/land conditions

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