Detection of active landslides by DInSAR in Andean Precordillera of San Juan, Argentina

Abstract

Landslides are downslope mass movements, which implies the combination of natural complex processes and sometimes affect anthropic resources. Many researchers inventoried landslides in the Argentinian Andean Precordillera by using aerial photography, satellite images, geomorphological analyses and GPS measures. Those located in latitudes between 31°S and 34°S have been mainly linked to seismic activity. However, due to the inaccessibility of sites, permanent monitoring has proved difficult. In this contribution, we detect three active landslides occurring in the Andean Precordillera of San Juan province using Differential Interferometric Synthetic Aperture Radar (DInSAR) based time series techniques and preliminary characterize its geomorphology. We use data provided by ESA's Sentinel 1 (C-Band SAR), Sentinel 2 (Optical) acquired between October 2014 and December 2018. The observed landslides are located at unstable hillsides oriented to the West and their deposits could potentially end in the San Juan River. As a result of the time series analysis, we interpreted that the three landslides seem to be reactivated by Illapel Mw 8.3 Earthquake (September 16th, 2015). In addition, one of them, has an acceleration at the beginning of 2016, linked to rapid snow melt.