Análisis automático de la susceptibilidad de las inestabilidades de laderas provocadas por terremotos en un sector de la cordillera de los Andes, Ecuador

Resumen

In this paper, we performed a regional susceptibility assessment of earthquake-triggered slope instabilities (landslides and rockfalls) in a sector of the Ecuadorian Andes (Chimborazo area). In this way, we obtained the critical acceleration and Newmark displacement, parameters related to susceptibility, considering dry and saturated conditions on the slopes. Average values of geotechnical parameters obtained from bibliography were assumed in the calculations using geological maps at a 1:100,000 scale, and the slope gradient from the digital elevation model. Seismicity was considered by means of a probabilistic scenario for a return period of 475 years and taking into account the site effects: soil and topographic amplification. The resulting maps are useful to identify areas of potential hazard and to locate areas of interest for further detailed studies. The most susceptible areas are mainly located in the slopes which are strongly incised by the drainage system, and related to volcanoes and sedimentary lithologies. However, these results should be taken as a first order estimation, because of uncertainties and assumptions used in the calculations and the absence of an inventory of previous slope instabilities which allows validation.