May 2012, Preonzo, Switzerland
A spectacular rockslide occurred in May 2012 in the area around Alpe di Roscera above Preonzo, Switzerland, involving more than 300,000 cubic meters.
The area involved was monitored by extensometers installed on the main cracks and remotely by an IDS IBIS-FL interferometric radar provided and operated by our local partner in charge of measurements, Geopraevent AG. The radar, specifically designed to detect sub millimeter displacements and movements in slopes, was deployed at a distance of 2 km from the unstable slope. At this distance the radar was able to divide all of the area involved into cells of 4x8 meters and calculate the relative displacement for each cell.
During April the landslide accelerated from 1 mm per hour to 3mm per hour and in May, after heavy rainfall, the entire area collapsed.
The radar was able to give this information to the operators of Ticino Canton almost in real time, improving their reaction to clear the area involved and to avoid any possible danger. The Ticino Highway was really close to the landslide. IBIS-FL was also able to detect any movement after the landslide helping the operators to assess that the area was not moving anymore and to exclude the chance of a second landslide.
A full description of the event is available on Geopraevent's website (in German) here.
Video of the landslide can be viewed on YouTube here