Abstract
Construction of offshore wind turbines, via impact pile driving, generates and radiates intense acoustic and sediment borne energy through the water column and ocean bottom. The acoustic waves generated by impact pile driving include interface (Scholte) and shear waves in the ocean bottom in addition to compressional waves in the water column and sediments. The particle motion component of acoustic energy is particularly important to fishes and invertebrates. Scholte waves contribute significantly to the particle motion generated in the seabed and have maximum amplitude at the seafloor. Scholte wave contribution to the measured data is identified using Random Decrement technique in this study. Data measured during the construction of the Coastal Virginia Offshore Wind (CVOW) project are analyzed. The CVOW project involved the construction of two 6-megawatt wind turbines located 43 km east of Virginia Beach, Virginia. The turbines were pinned to the seabed using mono piles of diameter 7.8 m. A suite of particle motion sensors, including Ocean Bottom Recorders (OBX), was deployed to monitor the acoustic pressure and particle velocity on the seabed during December 2021 to January 2022. To examine the potential effects of sound on fishes and invertebrates, the behavioral thresholds and behavioral audiograms of some of these animals to the particle motion component of sound were compared to the measured data. These measurements were part of the Bureau of Ocean Energy Management (BOEM) sponsored Real-time Opportunity for Development Environmental Observations (RODEO) Program [Work supported by Bureau of Ocean Energy Management (BOEM)].