Evolution of large-scale gravitational deformations in tectonically-controlled mountain slopes

BUCCI F., CARDINALI M., FIORUCCI F., GUZZETTI F., SANTANGELO M., 2013, Evolution of large-scale gravitational deformations in tectonically-controlled mountain slopes, 8th International conference (AIG) on Geomorphology, 2013, Parigi, 2013,
URL: http://www.cnr.it/prodotto/i/273239

Evidences of large-scale gravitational movements evolving close to Quaternary faults have been recognized in the north eastern Sicily (south Italy) through the visual inspection of multi-scale and multi-temporal aerial photographs. Geomorphological and photo-geological survey have defined the relationship between the gravitational displacements and the tectonically-controlled landscape modifications conditioned by the presence of fault planes crossing the mountain slopes. In most cases the faults played, or are playing, an active role in increasing the local relief. Furthermore their activity represents the main geomorphic factor conditioning the gravitational movements. These mass movements may have developed in response to the slope weakening subsequent to multiple earthquake events, thus they occurred in the same time period of the Quaternary fault activity. In other cases the faults have also played a passive role by forming the boundary of the sliding masses and coincide with the slip surfaces. In both cases the evolution of the large-scale mass movements is conditioned by the incision of the hydrographic network in response to regional Quaternary uplift. The related erosion causes modifications of the slope morphology and the exhumation of weak discontinuities which may lead to slope instability. The spatial association of Quaternary faulting and large-scale gravitational movements greatly increases the hazard in fault-controlled mountain front landscapes. The evolution of tectonic displacement by coseismic offset may represent a potential cause for the sudden and catastrophic evolution of the gravitational movements. After their emplacement, the large-scale landslide bodies are deeply dismantled by the recent morphogenesis, including recent and present-day landslides that can propagate without any evidence of tectonic displacement and further increase the local landslide hazard.

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