Influence of freeze-thaw cycles on microseismic activity on a mountain slope in the Italian Alps

The risks associated with rockfalls at high altitudes have grown in recent years. In order to better comprehend the causes of this increase in mountain slope instability and to establish whether particular climatic conditions can be counted among these causes, microseismic and thermometric monitoring systems were installed around the J.A. Carrel hut (Matterhorn Peak, Italian Alps) as part of the Interreg III Alcotra “PERMAdataROC” project. A detailed analysis of data from a 6-month recording period has highlighted a spatial concentration of the microseismic activity to within 10 m of the surface on the western side of the investigated slope, while a correlation of these data with thermal information has shown that the temporal concentration of the microseismic activity could be traced back to a transition from warm to cold periods. As alpine permafrost has been encountered in the area, with an active layer of between 0 m and 7 m, the results of this investigation are also useful to document the type of activity that is underway in the active layer of the slope.