The 2010 rockfall event in stein an der traun -causes and triggers

On January 25th 2010 at about 8 p.m. a block of 432 m³ volume and 1,026 t weight was released from a conglomerate face, apparently without warning, destroying a family home in the village of Stein on the river Traun. Only two of the four inhabitants could be saved out of the debris. After this event, the question arose whether the rockfall could have been foreseen or if such spontaneous incidents are abrupt and unpredictable. This paper presents the studies conducted to reconstruct the processes leading to the event. The investigations included field mapping, geodetic survey, laser scanning and stereographic photogrammetry of the rupture face, mineralogical analysis of sinter crust thin sections, inventory of the block dimensions and reconstruction of the collapse kinematics, analysis of the weather data prior to the event and a 2D finite element calculation (Phase2) using the geometry of the overhanging conglomerate strata.