A borehole extensometer is an instrument that measures vertical land motion caused by changes in aquifer thickness. A borehole is drilled through the entirety of an aquifer system and the steel pipe is anchored at the base to the basement rock.
Extensometer - Rebound Damage
Detailed Description
Borehole extensometers are instruments used to measure vertical land motion caused by changes in aquifer thickness. If land surface rises due to aquifer rebound more than the extensometer was designed to handle, the uplift may bend the steel extensometer rod and tip the weighted fulcrum arm out of alignment, as shown in this animation.
Damage of this kind occurred at the USGS extensometer at Franklin, Virginia at some point between 1995 and 2015.
Modern extensometers are constructed with slip joints to prevent this kind of damage.
Sources/Usage
Public Domain.
Related
The Virginia Extensometer Network
Borehole extensometers are instruments that monitor land subsidence caused by aquifer compaction. They provide precise, high-resolution measurements of changes in aquifer-system thickness. These changes in aquifer-system thickness contribute to vertical land motion (VLM) across the Virginia Coastal Plain, and are driven primarily by groundwater level decline due to human water usage. The Virginia...
Borehole Extensometer
A borehole extensometer is an instrument that measures vertical land motion caused by changes in aquifer thickness. A borehole is drilled through the entirety of an aquifer system and the steel pipe is anchored at the base to the basement rock.
Extensometer - Aquifer Compaction
A borehole extensometer is an instrument that measures vertical land motion caused by changes in aquifer thickness. A borehole is drilled through the entirety of an aquifer system and the steel pipe is anchored at the base to the basement rock.
A borehole extensometer is an instrument that measures vertical land motion caused by changes in aquifer thickness. A borehole is drilled through the entirety of an aquifer system and the steel pipe is anchored at the base to the basement rock.
Related
The Virginia Extensometer Network
Borehole extensometers are instruments that monitor land subsidence caused by aquifer compaction. They provide precise, high-resolution measurements of changes in aquifer-system thickness. These changes in aquifer-system thickness contribute to vertical land motion (VLM) across the Virginia Coastal Plain, and are driven primarily by groundwater level decline due to human water usage. The Virginia...
Borehole Extensometer
A borehole extensometer is an instrument that measures vertical land motion caused by changes in aquifer thickness. A borehole is drilled through the entirety of an aquifer system and the steel pipe is anchored at the base to the basement rock.
A borehole extensometer is an instrument that measures vertical land motion caused by changes in aquifer thickness. A borehole is drilled through the entirety of an aquifer system and the steel pipe is anchored at the base to the basement rock.
Extensometer - Aquifer Compaction
A borehole extensometer is an instrument that measures vertical land motion caused by changes in aquifer thickness. A borehole is drilled through the entirety of an aquifer system and the steel pipe is anchored at the base to the basement rock.
A borehole extensometer is an instrument that measures vertical land motion caused by changes in aquifer thickness. A borehole is drilled through the entirety of an aquifer system and the steel pipe is anchored at the base to the basement rock.