Ground Condition Monitoring of a Landslide using Distributed Rayleigh Sensing

Summary This paper describes the use of Distributed Rayleigh Sensing (DRS), traditionally associated with acoustic sensing, to monitor low frequency activity on a hillside prone to landslides that is used as the British Geological Survey’s landslide observatory at Hollin Hill, UK. The observatory is instrumented with a variety of geological survey techniques and provides a unique opportunity to compare measurement systems that have very different principles of operation. DRS systems are responsive to both strain and temperature and this paper demonstrates that these quantities can be separated effectively at the sub-Hz range using a recently developed dual fibre technique. Diurnal temperature variations and strain changes induced by rainfall at the site are observed and correlated with weather data. The landslide site is being continuously monitored and the capabilities of the DRS system for long term sub-Hz monitoring, short-term event detection and low frequency seismic monitoring will be assessed over the coming months.