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.
Sources/Usage
Public Domain.