Sounds and vibrations in the frozen Beaufort Sea during gravel island construction.
Underwater and airborne sounds and ice-borne vibrations were recorded from sea-ice near an artificial gravel island during its initial construction in the Beaufort Sea near Prudhoe Bay, Alaska. Such measurements are needed for characterizing the properties of island construction sounds to assess their possible impacts on wildlife. Recordings were made in February-May 2000 when BP Exploration (Alaska) began constructing Northstar Island about 5 km offshore, at 12 m depth. Activities recorded included ice augering, pumping sea water to flood the ice and build an ice road, a bulldozer plowing snow, a Ditchwitch cutting ice, trucks hauling gravel over an ice road to the island site, a backhoe trenching the sea bottom for a pipeline, and both vibratory and impact sheet pile driving. For all but one sound source (underwater measurements of pumping) the strongest one-third octave band was under 300 Hz. Vibratory and impact pile driving created the strongest sounds. Received levels of sound and vibration, as measured in the strongest one-third octave band for different construction activities, reached median background levels <7.5 km away for underwater sounds, <3 km away for airborne sounds, and <10 km away for in-ice vibrations.
Greene
Charles R
CR
Greeneridge Sciences, Inc., 1411 Firestone Road, Goleta, California 93117, USA. cgreene@greeneridge.com
Blackwell
Susanna B
SB
McLennan
Miles Wm
MW