Large volume landslides in the central andes of chile and argentina (32º-34ºs) and related hazards

Abstract

Large landslides are a common geomorphological feature of the Central Andes of Chile and Argentina. The highlands usually present landslide relicts of different types and volumes located in glacial valleys, including outsized rock slides and avalanches of millions of cubic metres up to cubic kilometres of volume. Even though the main trigger mechanisms of these events are not clear yet, being mostly interpreted as seismic in Chile and ambiguously climatic or seismic in Argentina, there is no doubt about their key role in the geomorphological evolution of Central Andes. Besides the direct hazard of landsliding in slope areas and surroundings, usually with little population, large volume landslides can also induce indirect hazards far away from the landslide original site, due to rock avalanches and/or debris flows, reaching inhabited places and threatening critical facilities for large cities such as Santiago or Mendoza. Landslide dams have formed lakes of different size, which slopes are susceptible to rock avalanches that may fall into the lakes producing catastrophic flooding downstream due to dam overtopping or failure. Examples of historic events in the Central Andes are revised and a preliminary description of hazards in the study area along with identification of necessary research for full hazard and risk assessment are presented.