At sea, large arrays of airguns (mechanical
sources that rapidly eject compressed air) provide the sound energy
which is detected by many hydrophone sensors typically forming a
3.5 km long, 240-channel streamer that is about 10 cm in diameter
and towed behind the ship. Sensor outputs and other essential information
are recorded by an onboard computer system.
Sophisticated computer processing of the vast quantities of data
is necessary before the optimal subsurface images of geological
structure are obtained. The first phase of such processing is again
done through contracts awarded on the basis of competitive bidding
to specifications prepared by LITHOPROBE seismologists.
But only then do the experts really get to work. It's complicated
stuff, a highly sophisticated "fine tuning" of processing
parameters, and careful "massaging" of many.htmlects of
the huge volume of seismic reflection data. This comes into play
at different stages of processing, and can significantly augment
the geological and other information that can be derived from the
data. The second phase of processing addresses these.htmlects through
selective reprocessing of the data.
In this, the LITHOPROBE Seismic Processing Facility at the University
of Calgary and Seismic Research Nodes established at nine universities
across the country, plus the major facility developed at the Geological
Survey of Canada in Ottawa and subsidiary facilities at offices
on the east and west coasts, are key contributors.