The review of recent bathymetric and geophysical data collected in the framework of several research and cartographic projects have allowed a detailed reconstruction of the morpho-structural setting and the (neo)tectonic evolution for both the Alpine and Apennine margins of the Ligurian Sea (Italy). The widespread occurrence of erosional processes and sediment mass movements along the steep continental slope and within the system of submarine canyons reflect the close correlation between the active tectonics and the recent morpho-dynamic evolution of the Ligurian Margin. This relation is better constrained in the western sector (Alpine) of the Ligurian Sea, where the recent uplift of the continental margin is associated to a well-developed system of inherited structures reactivated under a compressive/transpressive regime and widespread seismicity. In the eastern sector, where the seismicity is lower or absent, the mass movements are limited to few areas (e.g., the Portofino slope) coinciding with seismic clusters. Additionally, this sector is characterized by moderate and episodic fault reactivations under a compressive regime. The evidence of compressive deformation along the inherited fault systems has been revealed in some areas of the Ligurian Sea where the post-drifting extensional tectonics is interrupted by episodic tectonic inversion (at least) during the Middle–Upper Miocene and the Plio–Pleistocene until present.

Integrated remote sensing techniques, such as photogrammetry from unmanned aerial vehicles (UAV), mobile laser scanners (MLS) and multibeam echosounders (MBES), are particularly effective in detecting and measuring coastal and seabed features and their modifications over time (4D analysis) induced by sea storms. In fact, these techniques allow the production of very high-resolution 3D models, with a continuum between above and below sea level. The present research is focused on the area of Portosole Marina (Sanremo, Western Liguria), affected by a severe sea storm in October 2018 and the following restoration. Two integrated 3D surveys were performed in February 2019 and in November 2019, obtaining accurate and reliable high-definition digital surface models (DSMs) in both emerged and submerged areas. The comparison between the two surveys highlighted volumetric changes in the seabed induced by the sea storm and the effects of a temporary worksite on the emerged and submerged breakwater. In particular, a total deficit of sediments of about 5000 m³ caused an average lowering of about 4 cm over the entire area, concurring with the breakwater instability. This study aims to contribute to the understanding of coastal system resilience within ongoing global climate changes, that is, increasing the intensity of extreme events in the Mediterranean area.

The north Ligurian margin is a complex geological area in many ways. It has witnessed several phases of highly contrasting deformation styles, at both crustal scale and that of shallower cover tectonics, simultaneously or in quick succession, and with significant spatial variability. This complex interplay is mirrored in the resulting intricate structures that make it hard to identify active faults responsible for both, the significant seismicity observed, and the tectonic inversion undergone by the margin, identified at longer time scales on morphostructural grounds. We present here the first preliminary results of the leg 1 of SEFASILS cruise, conducted in 2018 offshore Monaco, in an effort to answer these questions by means of modern deep seismic acquisitions, using multichannel reflection and wide-angle sea-bottom records. Some first interpretations are provided and point towards an active basement deformation that focuses at the limits between main crustal domains.

Geomorphological survey and mapping of the emerged and submerged coastal areas, particularly addressed to evaluate sea cliff instability within the assessment of coastal hazard and risk mitigation measures, require high resolution and georeferenced spatial data. Remote sensing techniques fully satisfy these needs and allow to obtain all information in a single short-lived survey campaign. An integrated survey by means of laser scanner and multibeam techniques coupled with aerial photos interpretation has been experienced along the rocky coast of the Gallinara Island (Western Liguria, Italy). The small extent of Gallinara, together with its particular meteo-marine climate conditions, makes the island a noteworthy case study. Multibeam and laser scanner technologies allowed to reconstruct the submerged and emerged rocky coast at high resolution. The accuracy of the 3D surface reconstructed by means of laser scanner used in profiler mode was tested and validated, by comparing with the static laser scanner survey method. The resulting data allowed to obtain significant geological and geomorphological information leading to the definition of rocky cliff stability conditions.

The Ligurian continental shelf is a terrigenous platform characterized by variable extension and subsidence of the continental margin and thick accumulation of sediments originated by repeated sea-level oscillations. Its genesis and evolution occurred during the Plio-Quaternary, even if early erosive modelling in some sectors has been dated to the Late Miocene. The present morphology of the shelf is the result of transgressive–regressive Quaternary cycles. Using a high-resolution seismic grid of more than 1000 km, we have been able to define the seismostratigraphic characteristics of the Ligurian Sea shelf. On the basis of our studies, it has been possible to describe in detail the seismostratigraphy of the Late Quaternary and Holocene sediments that cover the shelf to various depths, in terms of sedimentary sources, for the purpose of distinguishing ‘relic’ deposits suitable for nourishing beaches undergoing erosion. From this detailed study of the evolution of the most superficial deposits, it is possible to distinguish between different sedimentary bodies deposited during a transgressive phase and located at a water depth ranging between 20 and 70 m; they are represented by relic sands cropping out at the sea bottom due to a relatively thin Holocene drape and could be explored for beach nourishment programmes.