Integrated geostructural, seismic and infrared thermography surveys for the study of an unstable rock slope in the Peloritani Chain (NE Sicily)

Abstract

This paper presents a multidisciplinary study about the instability of a rock slope on Peloritani Chain, northeastern Sicily. Several rockfalls affected the studied slope in the last decades, also causing the disruption of the main road, connecting the shore villages to the city of Messina. The complex geology and tectonics are the main causes of the poor mechanical properties of the rocks, exacerbated by high fracturing and weathering. Geostructural surveys allowed identifying the main discontinuity sets, most of which matches with the regional fault systems. Kinematic and stability analyses were carried out to define the main failure typologies and to realize two models describing the past rockfalls, as well as possible future events. For the deep investigation of the slope, horizontal borehole drilling and seismic active prospecting were performed so to estimate the thickness of the rock with poor mechanical properties. The contours of the most unstable areas along the slope have been better outlined through infrared thermography images, giving information about the thermal radiance behavior of the rock constituting the surface slope.The integrated approach of different methodologies, besides defining the instability features of the study area, demonstrates the reliability of such techniques, particularly in a geologically complex region where rockfalls represent one of the main causes of landslide fatalities.