ABSTRACT
This chapter describes the approach followed to develop an early warning system to forecast raininduced rapid flowslides in pyroclastic soils covering mountains in Campania. In the region of Campania flowslides in pyroclastic unsaturated soils, covering fractured limestone substrata, are widespread along coastal and western mountains. Flowslides occur as a consequence of very intense rainfall, after a more or less long-lasting wet period. Post-failure movement is catastrophic, due to the high velocity, long run-out and large landslide body. In Campania, soil involved in landslides is of pyroclastic origin, in general non-plastic, and initially unsaturated, with suction providing a significant contribution to shear strength. Early warning systems operating in Campania are based merely on statistical interpretation of measured rainfall. Rains cumulated over different time intervals, whose upper limit is the current time, are compared with threshold values obtained by interpreting past rainfall events associated to triggering of landslides.
