| Περίληψη: | The Gulf of Corinth is the second most active continental rift in the world and thus a much-studied natural laboratory for analyzing details of rift history. The Gulf of Lechaion sited S-E of the Corinth Gulf is the least studied area of the active Corinth graben. Although, the study of the Lechaion Gulf renders great importance as its formation is estimated to constitute an early rifting stage, where the evolution of the Corinth Gulf started. Therefore, more offshore seismic surveys combined with the already acquired data in this least studied part, will shed light to the tectono- sedimentary evolution of the eastern end of the Corinth rift. Besides the geological importance, Lechaion Gulf hosts the ancient harbour of Lechaion, which is of great archaeological significance and was built at 600BC, a period of zenith for ancient Corinth when its military and naval activities flourished. The coastal installations of the ancient harbor are still visible today, though part of them are partly or completely submerged due to the glacio- eustatic and tectonic movements in the area during Quaternary.
The present thesis aims to the reconstruction of the coastal palaeoenvironment of the ancient harbour of Lechaion and the recent geological activities nearby the submerged installations through the interpretation of the seismic stratigraphy and the seafloor morphology data.
The survey was conductedin three sessions, at November 2013, 2014 and 2015 and the data were collected with high frequency 3.5 kHz Pinger type subbotom profiler, where an area of 8,5 km2was scanned and 146 routes with 145,4 km length of seismic data were collected, reaching a maximum depth of 60m below the sea surface. The seismic profiles were then processed with specialized programs at the Laboratory of Marine Geology and Physical Oceanography.
The digital process enabled the design of bathymetric maps, isopach maps and also 3D models depicting the marine geomorphology around the harbor area and the sediment distribution near the ancient installations.
The composition and processing of all these seismic data enabled the estimation of the chrono- stratigraphy, paleo- morphology and geological regime of the ancient harbour of Lechaion.
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