six months, recharging itself from its own power supply. Applied Acoustics' technicians, in conjunction with the university, tackled this challenge by developing a seismic energy supply capable of firing a 4.8KJ shot using energy harnessed from the sun. A series of solar cells were incorporated into the unit to recharge the capacitor banks. The successful arrangement meant that with the buoy drifting at an average speed of 5 km/day, the system could fire the sparker every 50m of movement. The reflected seismic energy, received by a single hydrophone, is digitized and recorded, and sent to Bergen via the Iridium Satellite Network. This enables the University's scientists to monitor the operation remotely, returning to the region to retrieve the equipment at the end of the project. Three of these drifting seismic buoys are planned for further deployment in the Spring of 2009. Elsewhere in the Polar region, Applied Acoustics' geophysical capabilities have been put to the test in a different way. Its 6000J Delta Sparker with CSP-S energy source have been used in geohazard surveys off the northern Alaskan coast to establish the presence, or not, of shallow gas, active faulting and potential
hydrate zones. The Ultra High Resolution (UHR) multichannel seismic surveys used a 48-channel streamer at 6.25m spacing in conjunction with the multi-tip Delta Sparker array. The deployment of the CSP-D and
Delta Sparker system offered speed of mobilization as it required only a two-man operation and a readily available single-phase generator on a vessel of opportunity rather than a cumbersome compressor and air gun arrangement on a dedicated platform.
Pictured left is the Delta Sparker about to be deployed with its hydrophone streamers. The equipment is on the deck of a survey vessel operating in the Chukchi Sea off Alaska's north coast, undertaking a geohazard survey in October 2008. www.seadiscovery.com Marine Technology Reporter 13
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