The application of surface exposure dating method in case of Veliki vrh rockfall (Karavanke Mountains, Slovenia)

The use of terrestrial cosmogenic nuclides (TCN) has revolutionized Earth surface sciences over the last decade by their capacity to quantify geological surface processes. The uniqueness of these nuclides lies in their property of being produced in the top few meters of the lithosphere during exposure to cosmic radiation. There are various types of application of surface exposure dating such as chronological constraints on the timing and rates of environmental changes (glacial history, erosion) and hazard recurrence frequency (landslides and seismic activity). The method was used also in the case of Veliki vrh rockfall located in Karavanke Mountains (Slovenia). There are no reliable historical data about the rockfall event beside the oral heritage in form of a fairytale describing the catastrophic falling of rocks over the settlement in the valley, forcing the survivors to establish a new settlement (Tržic) further downstream. However, there are numerous written records about a historic rockfall (induced by an earthquake) taking place about 46 km away at Dobratsch, Carinthia on 25th January 1348 thus; it seems very likely that the same earthquake triggered both rockfalls. Surface exposure dating method has been applied on samples taken from the fresh bedrock and big blocks obviously originating from the Veliki vrh rockfall and the results are confirming our
hypothesis. They have also importantly improved geomorphologic interpretation of the area.