Analog dial gage (left) and a digital linear potentiometer (right)
Detailed Description
An analog dial gage (left) and a digital linear potentiometer (right with blue barrel) used to measure land-surface movement in response to aquifer system deformation at the USGS Nansemond extensometer. The potentiometer is the primary instrument for the extensometer with a resolution of about 0.00001 feet (0.003048 millimeters) and a travel range of 0.328084 feet (100 millimeters). The dial gage can be read to a precision of 0.0001 inches and has a range of 1 inch.
Sources/Usage
Public Domain.
Related
The Virginia Extensometer Network
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Along the Atlantic Coast, a 2000+ ft deep hole has been drilled by the USGS to assess the issues of groundwater pumping, relative sea-level rise, and land subsidence. This video shows the drilling of the first extensometer to measure land subsidence in the North Atlantic Coastal Plain in 30+ years. Land subsidence has been observed at various locations in the southern Chesapeake Bay region at...
Related
The Virginia Extensometer Network
Land Subsidence on the Virginia Coastal Plain
Nansemond Extensometer
USGS Extensometer Drilling in Virginia
Along the Atlantic Coast, a 2000+ ft deep hole has been drilled by the USGS to assess the issues of groundwater pumping, relative sea-level rise, and land subsidence. This video shows the drilling of the first extensometer to measure land subsidence in the North Atlantic Coastal Plain in 30+ years. Land subsidence has been observed at various locations in the southern Chesapeake Bay region at...