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We present here for the first time a morpho-structural study of the submarine sector of the Ustica volcanic edifice, located in the south-western Tyrrhenian Sea, considered as an inactive volcanic system, middle Pleistocene in age. The main aim of this research study is to unravel the submarine dynamics along the slope sectors of the Ustica volcano, in order to provide new insights on one of the most tectonically active regions of the Central Mediterranean during the Quaternary. We analysed and interpreted an integrated seismo-acoustic data set consisting of multibeam swath-bathymetry, sub bottom profiles, single-channel seismic reflection records, all of them acquired during the last two decades. The seismostratigraphic analysis indicates that the Ustica volcano is composed by a sequence of lava flows and pyroclastic products, whose geometry can be interpreted as the consequence of combined upward growing and northward shifting of the volcanic centers. The mapped geomorphological elements distributed along the submerged slopes were classified based on their specific morphogenetic process. The achieved results reveal that volcanic, tectonic, oceanographic and gravity processes interacted in shaping the complex current physiography of the volcanic edifice, which is characterized by extremely uneven submarine flanks. The northern region is characterized by the widespread occurrence of well-preserved cones, probably linked to the last submarine volcanic activity of the area. Along the eastern sector, elongate gullies and linear furrows locally incise the shelf break and develop downward producing slope failures. Furrows and gullies represent the main conduits for flushing sediments through various types of flows and mass wasting, from the shallow sectors to the bathyal plain. Along the southern and eastern region slope failures processes carve almost totally of the shelf edge and mainly propagate through retrograding collapses. Further on, the southern region is mainly shaped by E-W and N-S trending fault escarpments that may have triggered the largest slope failures of the area. The main results of this study contribute to improve the understanding of the geological processes and geodynamic activity between the Northern Sicily Continental Margin and the Tyrrhenian Basin and represent a baseline for assessing the geo-hazard potential on the Ustica Island We acknowledge the CARG Project (Geological Maps of Italy) funded by the ISPRA-Italian Geological Survey and the Italian National Research Projects MaGIC (Marine Geological Hazard along the Italian Coast) funded by the Italian Civil Protection Department.-- With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI) 18 pages, 13 figures, 1 table

Space-for-time substitution is a concept that has been widely applied, but not thoroughly tested, in some fields of geomorphology. The objective of this study is to test whether the concept of space-for-time substitution is valid in reconstructing the evolution of a submarine canyon-channel system in a passive progradational margin. We use multibeam echosounder data and in situ measurements from the south Ebro Margin to analyse the morphology and morphometry of a sequence of submarine valleys ordered in terms of increasing valley thalweg length. The morphological model of submarine valley evolution that we can propose from this analysis is very similar to established models in the literature, which leads us to conclude that time can be substituted by space when reconstructing the evolution of submarine canyon and channel systems in the south Ebro Margin. By extracting morphometric information from the application of the space-for-time substitution model to our data, we identify a series of morphological patterns as a submarine canyon evolves in a passive progradational margin. These include the geometric similarity of canyon planform shape, an increase in canyon draining efficiency and in the influence of flank slope failures, and an evolution towards equilibrium between canyon form and imposed water and sediment load without net erosion or deposition taking place. We also observe that canyon elongation is higher downslope and that the canyon undergoes an early stage of rapid incision similar to the process of >erosion narrowing> reported in terrestrial rivers. We demonstrate that the conclusions of our study are not limited to submarine valleys in the south Ebro Margin but are applicable to other margins around the world. © 2014 Elsevier B.V. This research was supported by Marie Curie Intra-European Fellowship PIEF-GA-2009-252702, Marie Curie Career Integration Grant PCIG13-GA-2013-618149 and HERMIONE (grant agreement 226354) within the 7th European Community Framework Programme, DOS MARES (CTM2007-66316-C02-01/MAR), GRACCIE-CONSOLIDER (CSD2007-00067), CASCADES (CTM2008-01334-E) and COSTEM (CTM2009-07806) projects. [...] AM, MC, GL and XT belong to CRG on Marine Geosciences, supported by grant 2009 SGR 1305, Generalitat de Catalunya 17 pages, 11 figures, 1 table Peer Reviewed