Catalogue of historical displacement waves and landslide-triggered tsunamis in norway

Abstract

Due to Norway’s more than 100,000 km long coast line and tens of thousands of lakes, Norwegian society is strongly exposed to displacement waves caused by landslides impacting into water bodies and to tsunamis caused by submarine landslides. In a database that goes back to the fourteenth century 270 such events are reported, related to rock falls, rock avalanches, debris flows, quick clay slides, snow avalanches and submarine landslides. By far the most severe effects are related to rock avalanches impacting into water bodies setting off waves with near-field heights of several tens of meters and far-field heights locally exceeding 10 m. Consequently, the highest numbers of fatalities (283) are related to those events reaching up to 73 fatalities in a single event. Our database has the potential to aid prediction of future landslide-generated displacement waves and tsunamis in Norway. However, it became evident that detailed data comprising landslide type, landslide volume, wave heights around the water body, only exist for few events and it is needed to study in detail future events in order to build better data sets that might be used for empirical prediction of those secondary effects.