The S-W Iberian margin is recognized to be a tectonically active area with major canyons and profuse evidence of mass wasting, representing a plausible region for tsunami generation due to submarine earthquake-triggered landslides. For this reason, submarine landslide susceptibility mapping becomes a major concern for regional mitigation risk strategy and offshore land-use planning. Given the offshore regional-scale context such endeavor is affected by multiple sources of uncertainties, which are best addressed within a probabilistic framework. Starting from a continuously updated landslide and fault catalog of the S-W Iberian margin, a series of probabilistic landslide susceptibility maps have been recently proposed for the region. The average overall performance of the maps as measured by the Receiving Operator Characteristic curve is good. However, it is interesting to examine the results at a smaller scale, focusing on existing well identified landslides. This is done here zooming within three major cases (Marquès de Pombal, Portimao, South Gorringe landslides) characterized by different failure mechanisms. The cases are examined to identify failure source areas assessing and quantifying limitations of outputs of the underlying slope stability model. Results are compared with previous studies of these landslides.
Stefano Collico, Marcos Arroyo, Roger Urgeles, Eulalia Gràcia, Marcelo De Vincenzi and Norma Peréz
Keywords: Submarine landslides, probablistic landslide susceptibility map, Iberian Margin, Marquès de Pombal landslide
Publisher: DFI