In geophysical surveys from a ship, a magnetometer measures the fluctuations in the magnetic signature of the rocks and sediment below the ocean floor.
The G-882 is a high resolution cesium vapor marine magnetometer, used to detect ferrous objects (e.g., anything made of iron, like pipelines, sunken ships, etc.) as well as for geophysical studies. The magnetometer detects variations in the total magnetic field based on the composition of the seafloor. Survey design and tow configuration is dependent on the goal of the study. Detecting ferrous objects requires the magnetometer to be towed a few meters above the seafloor in tightly spaced survey lines, whereas geophysical studies can use the magnetometer towed at the surface with larger distances between the survey lines. It can sample at up to 20 Hz and has a heading error <1 nT.
Specifications
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Manufacturer: Geometrics
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Model: G-882 Marine Magnetometer
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Weight: 40 lbs, up to 100 lbs with use of five weight collars
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Dimensions: 2.75x2.75x 54”
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Power Requirements: 24 to 32 VDC
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Tow Cable Breaking Strength: 1630 kg
Operational Characteristics
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Minimum Operational Depth: 20 m
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Maximum Operational Depth: The magnetometer is depth rated for 4000 psi, but in practice may be limited by the length of the tow cable
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Sediment Type: Any
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Limitations: The magnetometer should be towed at a distance four times the vessel length away from the ship. Therefore, on a 60 ft vessel, a tow cable of at least 250 feet is required.
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Power Outputs / Freq. Ranges: Passive
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Ship’s Requirements
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The magnetometer is light enough to be hand deployed by one person
See the multichannel seismic system for a comprehensive description. Also, check out the PCMSC Marine Facility (MarFac) web site for more information about field gear.
High-Resolution Multichannel Seismic System
PCMSC MarFac Field Equipment and Capabilities
PCMSC Marine Facility (MarFac)
- Overview
In geophysical surveys from a ship, a magnetometer measures the fluctuations in the magnetic signature of the rocks and sediment below the ocean floor.
USGS Pacific Coastal and Marine Science Center scientists and MarFac crew showing off the new magnetometer, named Magnetron, on fantail of Research Vessel (R/V) Parke Snavely. The G-882 is a high resolution cesium vapor marine magnetometer, used to detect ferrous objects (e.g., anything made of iron, like pipelines, sunken ships, etc.) as well as for geophysical studies. The magnetometer detects variations in the total magnetic field based on the composition of the seafloor. Survey design and tow configuration is dependent on the goal of the study. Detecting ferrous objects requires the magnetometer to be towed a few meters above the seafloor in tightly spaced survey lines, whereas geophysical studies can use the magnetometer towed at the surface with larger distances between the survey lines. It can sample at up to 20 Hz and has a heading error <1 nT.
Specifications
-
Manufacturer: Geometrics
-
Model: G-882 Marine Magnetometer
-
Weight: 40 lbs, up to 100 lbs with use of five weight collars
-
Dimensions: 2.75x2.75x 54”
-
Power Requirements: 24 to 32 VDC
-
Tow Cable Breaking Strength: 1630 kg
Marine magnetometer (in storage box on left) and chirp sub-bottom profiler on the back deck of R/V Coral Sea. Operational Characteristics
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Minimum Operational Depth: 20 m
-
Maximum Operational Depth: The magnetometer is depth rated for 4000 psi, but in practice may be limited by the length of the tow cable
-
Sediment Type: Any
-
Limitations: The magnetometer should be towed at a distance four times the vessel length away from the ship. Therefore, on a 60 ft vessel, a tow cable of at least 250 feet is required.
-
Power Outputs / Freq. Ranges: Passive
-
Ship’s Requirements
-
The magnetometer is light enough to be hand deployed by one person
-
- Science
See the multichannel seismic system for a comprehensive description. Also, check out the PCMSC Marine Facility (MarFac) web site for more information about field gear.
High-Resolution Multichannel Seismic System
Description of the high-resolution multichannel seismic system at the Marine Facility (MarFac) of the USGS Pacific Coastal and Marine Science Center, for seafloor mappingPCMSC MarFac Field Equipment and Capabilities
Learn about the USGS Pacific Coastal and Marine Science Center Marine Facility’s vast array of field equipment, sampling devices, and mapping systems, and our capabilities. Our engineers, designers, mechanics, and technicians have also designed and developed some of the specialized field equipment we use in field operations in the nearshore, in the deep sea, and on land.PCMSC Marine Facility (MarFac)
Learn about the USGS Pacific Coastal and Marine Science Center Marine Facility, or MarFac