Engineering geology and future stability of the El Risco landslide, NW-Gran Canaria, Spain

A 200 m long segment of the only main road in NW-Gran Canaria is built on landslide deposits near the village of El Risco. Structural mapping and analysis of the topography reveal that the N-S striking landslide head scarp is the upper part of a sub-circular failure surface. The southern side of the landslide is delimited by a much older E-W strike-slip fault. Prior to pavement resurfacing in 2006, cracks in the road tarmac at the northern and southern sides of the landslide suggested ongoing creep movement. Slope stability analyses suggest that peak ground acceleration (PGA) was the most likely trigger for the initial failure.