Abstract The European Marine Observation and Data Network (EMODnet) Project provides freely available data on European seas. The main purpose of EMODnet is to overcome the fragmentation and dishomogeneity of the available data, providing access to a harmonized and interoperable database. The EMODnet Geology Lot includes information at multiple scales on the seabed and its substrate ( http://www.emodnet-geology.eu/ ). The dataset on ‘Geological events and probabilities’ collects information on landslides, earthquakes, volcanic structures, active tectonics, tsunamis and fluid emissions. The Geological Survey of Italy, which coordinates the collation of ‘Geological events and probabilities’ data, provided guidelines to compile layers complemented by comprehensive and detailed patterns of attributes for each feature in order to characterize each type of geological event. Occurrences of events are often associated with each other, particularly in tectonically active areas. Geological events affect both submerged and coastal environments. Data gathered by EMODnet Geology provide a good basis for further studies, contributing to the outlining of different tectonic settings and providing support to the use of marine resources, as well as to the management of marine-coastal areas particularly regarding the identification and assessment of geological and environmental hazards.

ABSTRACT Two contrasting field relationships may reflect different tectonic settings of subduction initiation preserved in orogenic belts. “Hot” subduction initiation assemblages include a large ophiolite unit (up to kms thick, extending tens to hundreds of km along strike) with supra subduction zone (SSZ) geochemical affinity that structurally overlies a thin (<500 m thick) sheet of high-pressure (HP), high-temperature (HT), primarily metamafic rocks called a metamorphic sole. The ophiolite generally lacks burial metamorphism and includes variably serpentinized peridotite at its base. The sole structurally overlies subduction complex rocks made up of oceanic materials (igneous part of oceanic crust and overlying pelagic sedimentary rocks, and clastic sedimentary rocks of trench fill affinity) and/or passive margin assemblages; some of the subduction complex may be metamorphosed under HP-low temperature (LT) conditions (such as blueschist facies). The field relationships suggest initiation of subduction within young (<15 My) and “hot” oceanic lithosphere and that the sole represents the first slice(s) of material transferred from the subducting to upper plate. Examples include the Neotethyan and northern Appalachian ophiolites and units beneath them, and the Coast Range ophiolite and subjacent Franciscan subduction complex of California. “Cold” subduction initiation assemblages lack SSZ ophiolite and island arc components and a metamorphic sole. Instead, the upper plate above the subduction complex is made up of continental lithosphere that last experienced significant heating during a passive-margin forming rift event. The protoliths of the rocks subducted were >70 My in age at the time of subduction initiation. The HP-LT subduction complex is composed of slices of continental crust and oceanic crust representing parts of a hyperextended continental margin. These field relationships suggest initiation of subduction along a continental margin within old (“cold”) hyperextended continental lithosphere. Examples include the Apennine subduction zone, exposed in Calabria, Italy, and the Alpine orogenic belt, both remnants of the Alpine Tethys.

Abstract The collection of high-resolution multibeam bathymetry off the tectonically controlled Tyrrhenian Calabrian margin (southern Tyrrhenian Sea) allowed us to recognize several mass-wasting processes, including shelf-indenting canyons and several landslide scars ranging over different spatial scales. In this paper, we aim to characterize two large submarine landslides (S1 and S2) affecting an area of c. 7 and 14 km 2 , respectively; both scars occur within water depths of 700–1000 m on slope gradients of 1.5−3°. S1 is interpreted as a disintegrative landslide, because most parts of the related landslide deposits were evacuated from the scar and are not recognizable on the present-day bathymetry, whereas the landslide deposits of S2 are well-preserved and mostly confined within the scar, indicating a different post-failure evolution. Based on the integration of multibeam bathymetry and single-channel seismic profiles, both the landslides are interpreted as translational failures, whereas their different post-failure behaviour has been associated with differences in material properties (inferred by headscarp morphology), depth of their failure plane and frontal confinement. We also suggest that thick contourite deposits recognized in the area may represent an important preconditioning factor for the development of these landslides, similarly to that observed in the nearby Capo Vaticano scar complex.