Reassessment of the development and hazard of the Rampac Grande landslide, Cordillera Negra, Peru

The initial investigation analysed the complex Rampac Grande slope deformation from April 2009 (Landslides 8(3):309-320, 2011). The primary research in 2009 also identified an unrealistic explanation (raw mineral exploration) of the triggering of the landslide and the intention of the local authorities (from the administration centre of Carhuaz) to take measures to minimize the possible future risk to the local population. We also examined the adaptation measures introduced by the local authorities to reduce the risk for the local community. Unstable landslide material has been left after the 2009 event in the sources and transportation zone and several blocks were described as being only in a temporarily stable state. Landslide propagation could also follow the already existing lateral tension cracks identified in 2009. Areas of reactivation from 2012 were localized and triggering precipitation was evaluated. This study concluded that there is still a hazard of remobilization of specific parts of the landslide in Rampac Grande with potentially damaging effects on the buildings located close to the accumulation area.