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Balancing the West Point Extensometer

Detailed Description

Two USGS scientists balance the West Point extensometer's fulcrum arm prior to the instrument's activation.

Extensometers are highly sensitive instruments that measure changes in land surface elevation, specifically aquifer compaction. They can extend hundreds to thousands of feet into the ground, and they are balanced by a fulcrum arm at the surface. This carefully-balanced fulcrum reduces the friction of the extensometer pipe and allows for incredibly precise measurements.

The USGS West Point pipe extensometer (56J 49) has a total depth of 1,371 feet. Data for this site can be found on USGS Water Data for the Nation.

This extensometer is a part of the Virginia Extensometer Network.

Sources/Usage

Public Domain.

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