3-D multibeam bathymetry map and shallow sedimentary structure of the İzmir gulf

This study combines an interpretation of high resolution acoustic data collected from İzmir Gulf. Shallow sedimentary and morphological structures of this area are revaled acoustically using multibeam bathymetry, CHIRP high resolution seismic and side scan sonar data. The study includes morphology, active tectonics, shallow sedimentary structures, shallow gas accumulations and gas seeps in the region.Artificial structures like ships wrecks, dump areas and navigation channel are also present in the gulf. Acoustic data from İzmir Gulf indicate plenty of active faults. In the outer bay NNW-SSE directed normal faults get younger from east to west and in the middle bay E-W striking normal faults get younger from north to south.Using acoustic data, thickness of each unit is calculated from Late Pleistocene to Holocene in order to create isopach maps. Furthermore, the paleo-bathimetry map of last glacial period (last 18.000 years) is generated and then compared with current bathymetry of the study area. According to isopach map, the apparent sedimentation rate 2,5-4 mm/year in the NE coast, 0,8-1,7 mm/year in central basin and 0,5-0,2 mm/year.İzmir Gulf also has several shallow gas accumulation areas. In NE, the edge of Gediz delta is the area where shallow gas accumulations are present. The origin of gas is suggested to be biogenic at the edge of Gediz delta, but according to our acoustic data set it is not possible to suggest the origin of the gassy sediments of N-W part.