A team of researchers from Italy has used fibre optic sensors to create an early warning system for landslides. By embedding the robust sensors on the slopes likely to slide, the team hopes to monitor and detect large landslides and slow slope movements. The research will be presented at the Optical Society’s (OSA) annual meeting on 19 to 23 October in Tucson, Arizona, USA.
Landslides are preceded by a series of pre-failure strains that can be measured. Currently this monitoring is done with electrical sensors, but because of their vulnerability the team looked to the more robust fibre optic sensors.
Optical fibre sensors are used for a variety of structural monitoring applications, often in the harshest of environments, and are very sensitive to strain put on the material they are inbedded in. ‘Distributed optical fibre sensors can act as a nervous system of slopes by measuring the tensile strain of the soil they’re embedded within,’ explained Luigi Zeni, a professor at the Department of Industrial and Information Engineering at the Second University of Naples.
Zeni and his colleagues also found a way to combine several types of optical fibre sensors into a plastic tube that twists and moves under the forces of pre-failure strains. Researchers are then able to monitor the movement and bending of the optical fibre remotely to determine if a landslide is imminent.
The team said the findings demonstrate the potential of distributed optical fibre sensors as an entirely new tool to monitor areas subject to landslide risk and to develop early warning systems based on geo-indicators - early deformations - of slope failures.