Assessment of Earthquake-Induced Landslide Hazard in Greece: From Arias Intensity to Spatial Distribution of Slope Resistance Demand

The earthquake-induced landslide hazard in Greece is evaluated by means of a parametric time probabilistic approach. First, by taking into account the characteristics of seismicity affecting Greece, we calculated occurrence probabilities for different levels of seismic shaking expressed in terms of Arias intensity for a time interval of 50 yrs. Then, by utilizing the linkage of Newmark displacement with Arias intensity and critical acceleration, we mapped the spatial distribution of the slope strength demand that imply a 10% probability that displacement will exceed critical thresholds for potential seismic triggering of incoherent and coherent landslides. The obtained results suggest that the areas of western Greece and the broader region of the Gulf of Corinth are the most exposed to conditions of seismic triggering of both kinds of landslides. The derived slope strength demand maps could provide the basis for the assessment of whether particular slopes have a significant failure probability by comparing the estimated strength demand with the actual critical acceleration values calculated from slope material properties and slope angle. We exemplified this approach at a coastal area of the western Gulf of Corinth, where, by considering situations expected in dry and wet periods, we also demonstrated that earthquake effects on slope stability depend on the season of earthquake occurrence.