Influence of Numerosity and Distribution of Piezometric Data on the Performance of a Warning Model for Weather-Induced Landslides in Norway

Territorial landslide early warning systems (Te-LEWS) are widely applied worldwide to deal with weather-induced landslides over wide areas, typically through the prediction and forecasting of meteorological parameters. However, meteorological monitoring alone does not allow to take into account critical soil conditions controlling the triggering process. Depending on local conditions, landslides may be triggered in response to a large variety of weather events. Therefore, the integration of geotechnical monitoring data within warning models for weather-induced landslides at regional scale can provide supplemental information useful to determine the likelihood of a given weather event actually producing landslides. A methodology designed to integrate widespread meteorological monitoring and pore water pressure measurements is herein applied within 30 hydrological basins highly susceptible to weather-induced landslides in Norway. The correctness of the predictions in relation to different network configurations of the piezometers is evaluated through a series of parametric analyses. The results of a first application of the proposed warning model are also presented and discussed. This study should be considered as a first attempt to define the conditions for adopting an economically sustainable and technically reliable geotechnical monitoring strategy for predicting the conditions leading to the triggering of weather-induced landslides over wide areas.