A restored extensometer
![A picture of a restored extensometer](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/2017-03-16_restored-extensometer-usgs-central-valley.jpg?itok=gJwhl0bI)
Detailed Description
Example of a San Joaquin Valley extensometer the USGS restored in 2012. An extensometer is a tool that is used to evaluate the compaction and expansion of the aquifer system. USGS Photo by David Dillon
Sources/Usage
Public Domain.