How is a seismic survey done?
Onshore seismic operations usually use specialised trucks that carry a heavy plate that is vibrated to generate a seismic signal. Onshore seismic has been used in sensitive locations — including central Paris — without damaging buildings or the environment.
Geophones electronically pick up returning shockwaves and pass them on to recording equipment.
In marine operations, a specialised vessel tows a “seismic streamer”, or a collection of cables with seismic sources and hydrophones attached. The seismic sources use compressed air to produce acoustic energy. The hydrophones capture the returning sound waves.
Hydrophones and geophones are highly sensitive. They are deployed in clusters to optimise the reception and recording of sound waves. This provides information about rock types and possible oil or gas deposits.