What are Airguns?
Seismic surveys utilize arrays of airguns to produce powerful sound waves. Sudden releases of pressurized air bubbles create the sound source, with up to 20 guns fired at the same time, while “streamers” of hydrophones listen for echoes. Using sophisticated acoustic processing, these echoes can provide information about geological structures up to 40 kilometers below the sea floor. Seismic surveys are used by the oil and gas industry in its search for new hydrocarbon deposits and the monitoring of reservoirs as they are emptied. The “source level” of most airgun arrays can be 200dB or higher. For comparison, a loud rock concert is about 115dB and a jet engine at 100 feet is about 140dB. A typical seismic air gun array pulled by a ship might fire its compressed air bubbles into the ocean five or six times a minute — more than 7,000 shots in 24 hours. Because sound can travel hundreds or even thousands of miles under water, it’s not surprising that seismic airguns can be heard at great d
