Submarine canyon morphologies in the Gulf of Palermo (Southern Tyrrhenian Sea) and possible implications for geo-hazard

The continental shelf and the upper slope of theGulf of Palermo (Southern Tyrrhenian Sea) in the depthinterval ranging from 50 to 1,500 m were mapped for thefirst time with Multi Beam echosounder and high resolutionseismic. Seven submarine canyons are confined to theupper slope or indent the shelf-edge and enter the Palermointraslope basin at a depth of around 1,300 m. The canyonsevolved through concurrent top-down turbiditic processesand bottom-up retrogressive mass failures. Most of themass failure features of the area are related to canyonshapingprocesses and only few of them are not confined tothe upper slope. In general, these features probably do notrepresent a significant tsunami hazard along the coast. Thegeological element that controls the evolution of the canyonsand induces sediment instability corresponds to thesteep slope gradient, especially in the western sector of theGulf, where the steepest canyons are located. The structuralfeatures mapped in the Palermo offshore contributed to theregulation of mass failure processes in the area, with directfaults and antiform structures coinciding with some of thecanyon heads. Furthermore, the occurrence of pockmarksand highs that probably consist of authigenic carbonatesabove faulted and folded strata suggests a local relationshipbetween structural control, fluid escape processes and massfailure. This paper presents a valuable high-resolutionmorphologic dataset of the Gulf of Palermo, which constitutesa reliable base for evaluating the geo-hazardpotential related to slope failure in the area.