Geophysical Tools


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Geophysical Tools

Acoustic tools to produce images of the lake floor and underlying sediments.

Multibeam image of Lake Hvitarvatn
A Reson 7101 Multibeam, an Edgetech CHIRP sidescan sonar and additional gear

LLO uses a wide variety of geophysical tools in its studies of lake floor morphology and sedimentary processes. These acoustic tools allow LLO researchers to produce high resolution images of the lake floor and the underlying sediments.

High Resolution Surveys

High resolution bathymetric surveys can be collected with LLO's multibeam bathymetric system, which may be used on the RV Blue Heron or vessels of opportunity. The system consists of a 240 kHz Reson SeaBat 7101 multibeam coupled to an Applanix OceanMaster POS-MV motion and positioning system. The combined system is capable of producing high-quality hydrographic survey grade data in freshwater lacustrine systems up to 400 meters deep.

The RV Blue Heron is equipped with an EdgeTech dual frequency (100/400 kHz) Full Spectrum CHIRP sidescan sonar system. The system is depth rated to 300 m and includes an electric-hydraulic winch equipped with 1000m of armored tow cable. A small, hand-deployable EdgeTech 424 CHIRP sub-bottom profiler is available for seismic-reflection studies either from the Blue Heron, or from smaller vessels on small, remote lakes.

Sounders, Boomers and Airguns

Additional seismic-reflection systems available on the RV Blue Heron include a 28 kHz Knudsen Model 320B Echo Sounder, a Geopulse Boomer, and Bolt airguns that may be equipped with chambers of varying sizes. Data acquired with the boomer and airgun sources use a 24-element Benthos AQ-4 hydrophone streamer. Portable electrical generators and a high pressure air compressor are available for seismic surveys on remote lakes.

Processing Software and Other Equipment

The Geophysical Laboratory at LLO has computers equipped with software for processing and interpreting seismic, multibeam and sidescan sonar data (Parallel Geoscience SPW, Madagascar, and SU seismic processing packages, IHS Kingdom interpretation Suite, CARIS HIPS/SIPS hydrographic packages, and bottom classification packages). Supporting equipment includes: large format inkjet plotters, interactive whiteboard, and scanners.

Contact Nigel Wattrus regarding geophysical services.