tiltmeters

Tiltmeters are instruments that measure tilt or inclination of a surface or structure with respect to the horizontal plane. They provide the angle of tilt, typically in degrees or milliradians, and can be configured to measure a single axis or two axes of rotation. They are used in geosciences, engineering, and monitoring.

There are several technologies. Bubble tiltmeters and pendulum-based devices use a liquid-filled tube with a bubble or a pendulum that shifts with tilt. Electronic tiltmeters use MEMS accelerometers, capacitive sensors, or other transducers to infer tilt from gravity. Some borehole tiltmeters are installed in boreholes to monitor slow vertical or horizontal crustal tilt, while surface tiltmeters monitor structures such as bridges, dams, or skyscrapers. Tiltmeters may be single-axis or multi-axis.

Applications include seismology and volcanology (detecting ground tilt associated with magma movement or earthquakes), geodesy (crustal deformation), and civil engineering (structural health monitoring, slope stability, subsidence). In addition to monitoring, tilt measurements are used for alignment in optical and fiber applications.

Calibration and performance: accuracy depends on technology; typical resolutions range from microradians to arcminutes; drift and temperature sensitivity are common issues. Regular calibration, reference to a stable baseline, and environmental compensation improve reliability.

History: early tilt measurements used bubble levels in simple tubes; modern tiltmeters integrate with data acquisition and can be part of networks transmitting data in real time.

See also: inclinometer, tilt sensor, accelerometer, geodesy.