Triggering Factors And Tsunamigenic Potential Of A Large Submarine Mass Failure On The Western Nile Margin (Rosetta Area, Egypt)

A large-scale mass-transport deposit (MTD) called S16 was recognized on the upper slope of the western Nile margin, downslope from of a 30 km-long scarp located along the outer shelf. Regional mapping indicated that this MTD extends on nearly 505 km(2) and involved about 14 km(3) of Pleistocene-Holocene sediment. S16 was triggered between 10 and 9 kyr BP, during the Holocene sea-level rise and coeval pluvial period (increased river flow). The consequent enhanced sediment supply on the upper slope and the outer shelf area caused local overburdening. This factor combined with the potential accumulation of gas in the sediment and earthquake activity is thought to have been the main factor triggering the S16 MTD. From the estimated volume of the MTD, a potential slide-generated tsunami was numerically simulated using the GEOWAVE software. The results indicate that the similar to 80 km wide Egyptian continental shelf protects the main part of the coastline from a slide-induced tsunami coming from the Rosetta area. An exception is the part of the coastline around Alexandria because focussing and shoaling processes can be simulated very close to the coast.