In order to investigate the formation processes of the seafloor of Argostoli bay (Cephalonia Island, Ionian Sea), an extended geological survey was conducted to gather details about the near-surface geological framework. Methods used for the survey include high resolution subbottom seismic profiles (29.4 line kilometers; EdgetechCHIRP system at frequencies 2^-16 kHz) side-scan sonar backscatter surveys of the seafloor (approximately 67 line-km, Starfish 450F), single-beam bathymetry (approx. 67 line-km, Lowrance LCX-15MT Sonar system), and bottom sampling including bottom sediment grab samples (van veen grab sampler) and short sediment cores. The survey was focused at both ends of Argostoli Bay (i.e., Argostoli and Livadi inlets). Preliminary analysis of the sub-bottom profiles in the upper 12-20 m reveals a clear pattern of sediment layers, in both ends of the bay. The uppermost layers been deposited horizontally with small differences in their orientation in the area of Argostoli inlet,

while the presence of gas is more pronounced in Livadi inlet. Moreover, in Argostoli inlet a palaeo-surface is visible (probably the base of Holocene sedimentary cover) with minor channel features, likely indicating a shallow river valley. Side- scan mapping in combination with sediment samples and cores showed that the surface sediment consists mostly of finegained material, rich in organic matter over a gravel-lag deposit that may represent the transgressive surface in the area.