High-Resolution, Multichannel, Marine Seismic Surveying Using A Small Airgun Source

A high-resolution, multichannel, CMP, marine seismic reflection survey was carried out in Lake<br>Simcoe, southern Ontario, Canada, in June 1998, to examine large channel features within the glacial<br>sediments beneath the lake bottom. Over 300 line-kilometers were obtained at close line spacings<br>with an oil-filled hydrophone receiver array and a 1 cu. in. airgun fired accurately at 5 meter<br>horizontal intervals. Firing on distance was accomplished by integrating a real-time DGPS<br>(Differential Global Positioning System) and a computer-driven triggering system which adjusts the<br>firing rate depending on the ship’s velocity. The survey was conducted with an average boat speed<br>of approximately 4 knots (7 km/hour), and multichannel records were recorded on a Geometrics R-<br>24 seismograph at 2.2-3 second intervals.