Evaluation of the seafloor structural setting of Alamein New City offshore area, Egypt

Abstract

The Alamein New City is one of the newly established capital cities in Egypt. The study of the offshore extension is important to define the morpho-sedimentary seafloor features and evaluate the structure of the seafloor, sand resources, and the quantities of sediments that are responsible for beach renourishment. To achieve the purpose of the study, the marine acoustic geophysical techniques (MBES, SSS, and SBP) with video-camera attached in the ROV as a ground truth tool, were used. That has proven to be extremely powerful techniques in coastal applications.The integration of the marine geophysical data obtained from the bathymetric, shallow seismic surveys, and the validity of these data that was confirmed by SSS backscatter sonograph, in addition, the images obtained by using the ROV, divided the study area into three main zones. The southern zone (Z1) was rugged, which coincided with sandy mounds in the area, and has gradual backscatter strength from high to moderate with the direction of the prevailing current describing the rugosity of sand ripple. This zone has characterized by the thickest layer of sediment in the study area. Whereas the middle zone (Z2) showed the highest values of rugosity due to the slope where the ridge exists and has complex backscatter strength with finer thick of sediment. The northern zone (Z3) was characterized mostly by intermediate rugosity and gradual backscatter strength from high to moderate aligned with the direction of the current, describing the rugosity of sand ripple. The northern zone has the second thickest layer of sediment.The gentle sloping of the seafloor with the existence of the mounds and the submerged ridge are allowing the waves to break and scatter their energy provide natural protection for the beaches of Alamein New City.