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The Chirp II system is also an invaluable tool for verifying
the accuracy of requested core sample positions during SGE
programs. TDI-Brooks generally records at least one 1km survey
line over each core location prior to sample acquisition.
Real time high resolution Chirp II sub-bottom data can be
compared to seismic survey data provided by the client to
ensure that each core is being taken at the desired location.
This real time data also allows the field staff to make adjustments
to core positioning to better target the desired feature,
particularly where the target has an obvious surface or shallow
sub-bottom expression. A print out of each chirp line indicating
requested and actual core locations is provided to the client
at the end of each job.
Image
of target feature from client seismic
Waypoint
from client adjusted in field based on
real time chirp data
The CAP-6600 digitally synthesizes and transmits a linearly
swept, frequency-modulated Chirp pulse with resolution proportional
to the transmitted bandwidth. The Chirp output is a long FM
pulse which provides an additional 20 to 30 dB signal to noise
ratio improvement over conventional sub-bottom profiling systems.
This frequency-modulated pulse, combined with the matched
filter correlation, results in significantly increased resolution
and penetration. On board signal processing substantially
reduces transducer ringing and side lobes, which is imperative
for shallow water operation. The transmitted waveform is repeatable
from pulse to pulse in order to provide acoustic data that
is quantitative, allowing measurement of sonar data required
in sediment classification.
Utilitization:
The highest frequency systems are often used in engineering,
environmental, archaeological and other applications in which
the goal is to resolve layers in the upper one or two meters.
The low frequency system provides the penetration and visualization
of shallow geological structure to illuminate active petroleum
seep structures, mud volcanoes, faults, gassy sediments and
the BSR and provides a host of geological information with
which to refine core locations and understand recent geological
activity.
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