Distribution and causes of landslides in the eastern Peloritani of NE Sicily and western Aspromonte of SW Calabria, Italy

The Peloritani and Aspromonte areas are tectonically active mountainous regions of NE Sicily and SW Calabria, respectively, where landslides are the most common hillslope mass-wasting process. This study aims to elucidate the primary controls on the distribution and size of landslides in these two different landscapes. These regions, either side of the Messina Strait, have similar lithologies, but show different morphological characteristics in response to varied neo-tectonic activity and climate. Landslides were identified utilising aerial photographs and Landsat images. Frequency-area statistics were calculated to determine the length-scale of the most frequent interpretable landslides and compare our results with previous studies. The frequency-area power-law exponents (1.99 in Peloritani and 1.94 in Aspromonte) fall within the range of values that have been observed (2.0 +/- 0.5) in similar landscapes. The Peloritani Ridge, Sicily, has range-parallel normal fault segments with the majority of landslides occurring in their footwalls. There seems to be a strong coupling between tectonic activity and landslides, where slope instability is exacerbated by faulting, fracturing or jointing in otherwise low-permeability gneiss and granite bedrock. Conversely, in Aspromonte, Calabria, landslides are restricted to steep valley walls, and are absent from interfluves. This is because landslides are controlled by fluvial incision processes. These observations confirm a relationship between the spatial distribution of landslides and the processes controlling slope failures. (C) 2011 Elsevier BM. All rights reserved.