Strainmeters and tiltmeters

The techniques and instrument designs developed for continuously recording tiltmeters and strainmeters are reviewed. Consideration is given to short-base and long-base tiltmeters as well as to rod, wire, laser and borehole hydraulic strainmeters. Since a good design is difficult to achieve, it is necessary to select the goals an instrument must meet and be prepared to compromise on others. The importance of comparison tests is demonstrated, and it is concluded that good results cannot be gotten at low cost or without careful attention to details.