Marine seismic reflection data coupled with on-land structural measurements improve our knowledge about the active deformation pattern of the northern sector of the Malta Escarpment, a bathymetric and structural discontinuity in the near-offshore of Eastern Sicily. As favourably oriented to be reactivated within the Neogene Africa–Europe convergence, it is believed that the Malta Escarpment has a significant role in the recent seismotectonic framework of the Western Ionian Basin and the Hyblean foreland domain of SE Sicily, where some of the largest and most destructive Mediterranean earthquakes are located according to available historical catalogs. Offshore seismic data along with bathymetric grids illuminate the shallow subseafloor setting and allow more accurate mapping of the seafloor expression of previously identified faults in the area. The seismic interpretation and the near-fault sediment pattern analysis provide constraints on fault 3D geometries as well as on their through-time tectonic activity, suggesting also that part of the observed deformation may have been caused by nontectonic processes. Identified faults form currently an E-dipping, roughly N–S trending, and 60 km-long extensional belt deforming the seafloor with a significant displacement amount in the Ionian offshore between Catania and Siracusa. 3-dimensional parameters of faults were then used to derive expected magnitudes and their reactivation propensity. Empirical scaling relationships and forward methods point to a high seismic potential for the detected fault as well as predict the fault slip behavior according to the field-derived differential stress. This combined analysis along with faults displacement measurements pointed out how the longest and most continuous fault could be capable of generating M > 7 seismic events, putting forward strong seismotectonic implications for the adjacent and densely populated Hyblean Plateau. The expected magnitude and the estimated recurrence time interval are compatible with those inferred for large historical earthquakes in the area even if other offshore seismic sources cannot be ruled out.

FundingThis work benefits from founding from the University of Catania in the frame of the project "Multidisciplinary analysis of the deformation around active tectonic structures" (responsible G. Barreca) and partly from the MUSE 4D project -Overtime tectonic, dynamic and rheologic control on destructive multiple seismic events -Special Italian Faults & Earthquakes: from real 4D cases to models in the frame of PRIN 2017. Authors' contributionSG: work planning, conceptualization, seismic data interpretation, data analysis and interpretation of results, review of literature, figures preparation, writing the initial draft and final version of the manuscript. GB: seismic data interpretation, data analysis and interpretation of results, review of literature, writing the initial draft and final version of the manuscript, critical reading of the manuscript, funding acquisition. FG: POS496 seismic data acquisition and processing, critical reading of the manuscript. CM: review of the literature data, critical reading of the manuscript, funding acquisition, supervision, final approval of the manuscript. M-AG: planned the CIRCEE marine geophysical survey, seismic data acquisition, critical reading of the manuscript.

Volcanism and the Earth's Atmosphere Alan Robock and Clive Oppenheimer (Eds.)

Deformation bands, usually recognised in association with faults, are here analyzed in relation to a tight syncline fold developed in the Miocene Numidian turbidites of Sicily.Deposited above a growing thrust-wedge and then buckled during continued deformation, their porous sandstones form subsurface gas reservoirs elsewhere in the system and are analogues for deepwater systems in general. Structural data have been collected and statistically analyzed to characterise preferred orientations and size parameters (thickness, spacing, length) of deformation bands. Two distinct populations relate to folding: the most recent one is NE-SW oriented, which produced the most prominent structures, whereas an older one is partially obliterated. Microscopic investigation reveals porosity decreases within deformation bands with respect to host rock. The principal deformation mechanisms are grain rotation/sliding and porecollapse, consistent with folding having occurred under low burial conditions. Within the thrust wedge, near-surface folding is widespread, as indicated by growth strata. Thus we expect early-burial deformation bands of the types (compaction an shear bands) illustrated here to be a component of reservoir damage in subsurface examples.

The disastrous earthquake of 1693 AD caused over 60,000 causalities and the total destruction of several villages and towns in south-eastern Sicily. Immediately after the earthquake, a tsunami struck the Ionian coasts of Sicily and the Messina Strait and was probably recorded even in the Aeolian Islands and Malta. Over the last few decades, the event has been much debated regarding the location of the seismogenic source and the possible cause of the associated tsunami. The marine event has been related to both a submarine landslide and a coseismic displacement at the seafloor. To better define the most reliable sources and dynamics of the tsunami, we couple high-resolution marine seismic survey data with hydrodynamic modelling to simulate various scenarios of tsunami generation and propagation. Results from the simulations are compared with geomorphological evidence of past tsunami impacts, described in previous work along the coast of south-eastern Sicily, and within historical chronicles and reports. The most reliable scenario considers the 1693 event composed by two different tsunami waves: a first wave generated by the coseismic fault displacement at the seafloor and a second wave generated by a submarine landslide, triggered by the earthquake shaking. Tsunami modelling shows that a simultaneous movement between fault displacement and submarine mass movement could determine a destructive interference on the tsunami waves, resulting in a reduction in wave height. For this reason, the second tsunami wave probably occurred with a maximum delay of few minutes after the one generated by the earthquake and induced a greater flooding. The double-source model could explain the observation because in the course of other destructive earthquakes in south-eastern Sicily, such as that of 1169 AD, the associated tsunami caused less damages. This implies the need to better map, define and assess the hazard responsible for this type of tsunami events.