Deformation processes along the Calabrian compressive margin

Abstract

The Calabrian arc is a fundamental area to understand the tectonic evolution of the Apennine and Maghrebian foldandthrust belts within the framework of convergence between African and Eurasian plates in the central Mediterranean. The Calabrian arc has been the subject of several studies since at least the 1950s by geological and geophysical methods. Despite the large amount of collected data, geometry, kinematics, and tectonic evolution of the Calabrian accretionary prism are still poorly defined, particularly in the offshore region. Understanding the structure of the Calabrian accretionary prism bears important implications in the mitigation of hazards connected with the active tectonics of this region, particularly in marine environments. This thesis addresses the tectonics of the Calabrian convergent margin by using mainly offshore seismic reflection profiles spread over the entire Ionian Sea, in the central Mediterranean. In particular, geometry, kinematics, and timespace evolution of the Calabrian accretionary prism are studied and defined. In one case (Longobucco area, northern Calabria), we integrated structural, geological and termochronological analyses to define the oldest phases of accretion and growth of the Calabrian accretionary prism. Eventually, implications for the mitigation of natural hazards typical of active, or recentlyactive, convergent margins are considered. In particular, we analyzed two significant case histories: the Crotone megalandslides, which is a presently active margin spreading above a thick Messinian salt layer at very low rates; and the 1908 Messina tsunami possibly triggered by a large landslide which occurred off the Ionian coast of Sicily along the steep Malta Escarpment. Although several new or old questions remain open, results from this thesis shed new light on the tectonic evolution of the Calabrian accretionary prism and related subduction processes. For the first time, new industrial data have been interpreted and combined with previously published geophysical and geological dataset, to provide a complete view of this tectonically complex region.