Surface exposure dating of the Veliki vrh rock avalanche in Slovenia associated with the 1348 earthquake

Silke Merchel (1) , Irena Mrak , Regis Braucher (2) , Lucilla Benedetti (2) , Blaz Repe , Didier L. Bourlès (2) , Juergen M. Reitner

1 GFZ - German Research Centre for Geosciences - Helmholtz-Centre Potsdam
2 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement

Over 30 samples from bedrock and boulders from the Veliki vrh rock avalanche have been collected for surface exposure dating. The limestone rocks have been radiochemically treated to isolate and determine long-lived Cl-36 by accelerator mass spectrometry. It could be shown that the Veliki vrh rock avalanche from the KoSuta Mountain (Slovenia) event can be very likely linked to one of the major historical earthquakes in Europe happening on the 25th of January 1348. Taken into account independently determined denudation rates, inherited Cl-36 originating from pre-exposure at shallow depths (20-55 m) could be calculated. The high amount of inherited Cl-36, i.e. 17-46% of the total Cl-36, makes this site not suitable for a precise determination of the Cl-36 production rate as it was originally anticipated. Veliki vrh is a ``classic'' rock avalanche of high velocity. The slope failed in the upper part with a translational slide predominantly along the bedding planes, whereas dynamic fragmentation is the cause for further crushing of the material and the long runout. (c) 2014 Elsevier B.V. All rights reserved.

Domaines: Tectonique

Silke Merchel, Irena Mrak, Regis Braucher, Lucilla Benedetti, Blaz Repe, et al.. Surface exposure dating of the Veliki vrh rock avalanche in Slovenia associated with the 1348 earthquake. Quaternary Geochronology, 2014, 22, pp.33-42. ⟨10.1016/j.quageo.2014.02.002⟩. ⟨hal-01424611⟩