Geotechnical characterization of the landslides in the Paraná river cliffs of Santa Elena, Entre Ríos Province, Argentina

Abstract

Santa Elena city in the Entre Ríos province exposes huge cliffs over the side of the Paraná River. This
scenario of the city provides a wonderful view of the sunset on the river. However, the height and the
steep slopes of these cliffs pose a permanent hazard to people that live there. The landslides are the
main cause of backward movement of the cliffs. Both the stratigraphic features and increase of water
saturations by infiltrations play an essential role to trigger this type of landslides. The last big episode of landslides occurred in 2016, simultaneously with a strong El Niño Southern Oscillation event (ENSO), which caused high precipitation and flooding of the Paraná River. Through exhaustive
fieldwork, we could recognize the main structures that characterize the landslide mechanism.
Additionally, new data provided by six geotechnical boreholes helped us to understand the mechanic
that triggers the landslides. An appropriate interpretation of the type of movement and the identification of the causes, could be used to predict and build suitable engineering works to mitigate the impact of the landslides.