Geologists Monitoring Sediment during West Point Extensometer Drilling
Detailed Description
While drilling the 1420-foot-deep borehole for the West Point Extensometer, USGS geologists take the opportunity to learn all they can about the underlying geology. As they drill deeper, sediments are pumped out of the borehole. Geologists take samples of the sediments every 20 feet and note their composition. This information is used to determine which geologic units are encountered at which depths.
The 'mud' seen in this photo contains sediments from between 740 to 760 feet below ground surface at West Point.
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...
The West Point Extensometer
The West Point Extensometer

Installing GNSS at the West Point Subsidence Superstation

Geologists Monitoring Sediment during West Point Extensometer Drilling

Drilling Rig Feeding Pipe into the Borehole for the West Point Extensometer
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...
The West Point Extensometer
The West Point Extensometer

Installing GNSS at the West Point Subsidence Superstation

Geologists Monitoring Sediment during West Point Extensometer Drilling

Drilling Rig Feeding Pipe into the Borehole for the West Point Extensometer