Episodic landslide movement in Iceland studied using SAR interferometry

While there is abundant geomorphologic evidence for landslides in Iceland, it is in most cases unknown whether or not these landslides are actively creeping. Here we use Interferometric Synthetic Aperture Radar (InSAR) to assess its monitoring capabilities on three landslides that are known to be creeping and to survey large areas in East and Central-North Iceland in search for other creeping landslides that may exist. In one of the known cases, active creep can be seen in InSAR data acquired two years before cracks were discovered in the field and regular field monitoring started, which demonstrates the early warning potential of InSAR. In addition, we have discovered more than 30 locations of previously unknown landslide creep in the two study areas. The detected landslide creep typically exhibits variations in both displacement rate and aerial extent during the observation period, which clearly indicates episodic behavior of landslides in Iceland.