The potential of tiltmeters as a low-cost technology in baseline ground movement monitoring

Geothermal energy has received increasing attention in recent decades due to the net-zero emission targets. However, the impact of energy technologies that utilise the subsurface, lacks systematic understanding still. Such an impact is potential ground motion at the surface due to changes (thermal, chemical, pressure) induced at depth. Precise monitoring data and appropriate analysis methods could help on this. This study is part of a wider project on the use of abandoned underground coal mines for energy storage. Here, we test the potential of tiltmeters as a low-cost monitoring system, in providing information on tiny movements of the ground surface that could be used as baseline ground movement for areas that are relatively flat and without any known ground instabilities. We discuss our observations after a full year of measurements, the challenges faced in the analysis of data, mainly due to the effect of temperature on the measurements, and provide considerations on aspects of the monitoring design for similar applications.