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.
Virginia Extensometers Depth Comparison
Detailed Description
How Deep Do We Drill?
USGS borehole extensometers extend from the land surface all the way down to the basement rock at the bottom of the aquifers they are monitoring. These boreholes can be hundreds to thousands of feet deep! This graphic shows how deep four of the extensometers on the Virginia Coastal Plain extend into the ground by comparing them to the heights of some of the United States’ tallest buildings.
Extensometer Depths
- Franklin Extensometer: 860 feet below land surface
- West Point Extensometer: 1,371 feet below land surface
- Suffolk Extensometer: 1,620 feet below land surface
- Nansemond Extensometer: 1,960 feet below land surface
Compare this to the heights of some of North America's tallest buildings
- The Empire State Building: 1,454 feet
- Central Park Tower: 1,550 feet
- One World Trade Center: 1,792 feet
Extensometer sheds not to scale.
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...
Land Subsidence on the Virginia Coastal Plain
Land subsidence is a loss of ground elevation, often experienced as the ground slowly sinking over the course of years. In eastern Virginia, high rates of groundwater use is a major factor in the land subsidence affecting the area. The Virginia-West Virginia Water Science Center, with the help of our partners, has been monitoring land subsidence in the Virginia Coastal Plain since 1979 using a...
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.
Borehole Extensometer
Borehole Extensometer
Borehole extensometers are highly sensitive instruments which measure aquifer compaction. This infographic explains the various parts of a borehole extensometer, and is modeled after the USGS extensometer at Nansemond, Virginia.
Borehole Extensometer
Borehole extensometers are highly sensitive instruments which measure aquifer compaction. This infographic explains the various parts of a borehole extensometer, and is modeled after the USGS extensometer at Nansemond, Virginia.
Virginia Extensometer Network
This static map shows the locations of the three existing extensometers (red) in the USGS' Virginia Extensometer Network with the location of a fourth future extensometer (green). The basemap is of the Virginia Coastal Plain and shows the severity of groundwater depletion, with darker blue indicating greater groundwater depletion.
This static map shows the locations of the three existing extensometers (red) in the USGS' Virginia Extensometer Network with the location of a fourth future extensometer (green). The basemap is of the Virginia Coastal Plain and shows the severity of groundwater depletion, with darker blue indicating greater groundwater depletion.
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...
Land Subsidence on the Virginia Coastal Plain
Land subsidence is a loss of ground elevation, often experienced as the ground slowly sinking over the course of years. In eastern Virginia, high rates of groundwater use is a major factor in the land subsidence affecting the area. The Virginia-West Virginia Water Science Center, with the help of our partners, has been monitoring land subsidence in the Virginia Coastal Plain since 1979 using a...
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.
Borehole Extensometer
Borehole Extensometer
Borehole extensometers are highly sensitive instruments which measure aquifer compaction. This infographic explains the various parts of a borehole extensometer, and is modeled after the USGS extensometer at Nansemond, Virginia.
Borehole Extensometer
Borehole extensometers are highly sensitive instruments which measure aquifer compaction. This infographic explains the various parts of a borehole extensometer, and is modeled after the USGS extensometer at Nansemond, Virginia.
Virginia Extensometer Network
This static map shows the locations of the three existing extensometers (red) in the USGS' Virginia Extensometer Network with the location of a fourth future extensometer (green). The basemap is of the Virginia Coastal Plain and shows the severity of groundwater depletion, with darker blue indicating greater groundwater depletion.
This static map shows the locations of the three existing extensometers (red) in the USGS' Virginia Extensometer Network with the location of a fourth future extensometer (green). The basemap is of the Virginia Coastal Plain and shows the severity of groundwater depletion, with darker blue indicating greater groundwater depletion.