Spatial and temporal variations of rockfall activity at Schwarzenberg (Diemtigtal, Bernese Prealps)
Spatial and temporal rockfall activity was assessed in a subalpine forest stand at Diemtigtal lying in the transit zone of frequently passing, rather small rockfall fragments (mean diameter 10 to 20 cm). In total, 33 stem discs from previously felled Picea abies trees found at the foot of Schwarzenberg were sampled, and a total number of 301 rockfall events were dated to between 1724 and 2002 AD. Results show that the spatial distribution of rockfall changed slightly with time, and that rockfall activity increased considerably over the last century.
In contrast, magnitude presumably remained on a comparable level. The seasonal occurrence of rockfall showed a clear peak during the dormant season of trees, most probably in early spring. Furthermore, rockfall rates were positively correlated with temperatures, with higher temperatures resulting in increased rockfall activity. In contrast, correlation could neither be revealed with precipitation totals nor with the annual number of frost days.
Project leader : Department of Geography, University of Berne (GIUB)
Contact : Markus Stoffel
Perret, S., Stoffel, M. & Kienholz, H. (2006): Spatial and temporal rockfall activity in a forest stand in the Swiss Prealps – a dendrogeomorphological case study. Geomorphology 74(1-3): 219-231. [PDF]