Abstract

The recent development techniques of acoustic sound survey can provide clearly the inferences of seabed texture, grain size or habitat, seafloor bathymetry and sunken archaeology. Acoustic seabed classification and mapping are possible by using a wide range of acoustic imaging systems. The aim of this study is to get a recent seafloor mapping of the seabed characteristics applying side scan sonar sonography, single beam echo-sounding with QTC seabed classification data, remotely operated under water vehicle (ROV) imageries, and sediment analysis in the study area of the Abu-Quir bay, Alexandria, Egypt. Four types of backscattered patterns were recognized: Pattern of lighter tones corresponds to coarse and medium sediments, Darker tones pattern corresponds fine to very fine sand, tonal patches pattern confined to the transition zone from fine to coarse grained sediment. Moreover Pattern with isolated reflections belongs to archaeological remains and rocky outcrop areas. The seabed sediments of the study area were classified into four types; fine sand, medium sand, very fine sand and silty clay. The isolated reflections pattern has been interpreted as rocky outcrops and archaeological remains of the two ancient Greek cities, Heraklieon and East Canopus. The detection of scattered remains of archaeological structures assumed to be parts of historical blocks, buried archaeological feature. The large flat rocky area may be interpreted as the floors of the submerged cities. The borders of both submerged cities were delimited on the mosaic image where, Heraklieon may covered an area about 600 × 1000 m, while East Canopus may covered 550 × 800 m that situated 1.9 Km at the eastern side from the Abo Qir port.

Keywords: Abu-Quir bay; Acoustic imagery; Seabed classification; Single beam echo-sounder; Backscatter