The VW crackmeter is used to monitor movement at joints and cracks in concrete structures or rock. Typical applications include:

-Monitoring joints for unexpected movement to provide early warning of performance problems

-Monitoring joints and cracks in structures that may be affected by nearby excavation and construction activities.

-Monitoring cracks in structures that have experienced seismic activity.

Source:http://www.slopeindicator.com/instruments/jmeter-crack.php

Link to report of this instrument: CMA