Landslides: a climate change signal in the Central Andes

MOREIRAS S.M., OLMEDO V.E., DIAZ A.F.

Malargüe, Mendoza, Argentina

Simposio; Regional Climate Variations in South America over the Late Holocene; 2006

PAGES (Past Global Changes), IAnigla

Even through, landslides can be related to shaking movements in seismic areas, they have been widely linked to climate forcing. Their relation with extraordinary climate phenomena such as El Niño has been broadly referred for different regions around the world as well. Hence, frequency and activity grade of landslides generated by rainstorms constitute good proxies for climate change. Along the Mendoza river (32º L), in the Central Andes, summer rainstorms are a major factor for landslide distribution. The recurrence of rockfall and debris flows, varying from months to years in different places, is boosting due to climate change related to both precipitation and temperature increase in the Andes ranges. Greater water availability as consequence of the rapid snow thawing caused by higher temperatures, and intense rainfalls favour hillslope instability in this arid region. So, landslide frequency has been growing during the last three decades. Moreover, landslide frequency increases during ENSO warm episodes associated with increased precipitation, both greater snow accumulation during winter, as well as, intense summer rainstorms are recorded in these periods. As a consequence of global climate change, we suspect that landslide frequency may be higher in the future. These findings evidencing a greater potential landslide hazard regard to economical impact on our regional economy as an international road connecting Mendoza with Santiago de Chile is settled along the Mendoza river where more than 300 thousands vehicles is moving per year.