The seismic profiles were acquired in Lake Iznik in 2005, using a 3.5 kHz system (Geopulse, Geoacoustic) with a single channel streamer (20-elements AE5000, GeoAcoustics) and an array of four sub-bottom profiling transducers (Mod. TR-1075A, Massa, USA) as receivers. Shot interval was 1 second. For navigation, a 3x4m UWITEC aluminum platform ("R/V Helga") equipped with 4 inflatable tubes for flotation and a 25 HP outboard engine were used. The average speed of the vessel was 5 km/h. All 3.5 kHz data were digitized (Octopus 360, Octopus Marine Systems, UK) and processed (15 to 5000 Hz filtering) using Reflex software (Sandmeier Software, Germany). All profiles were interpreted using IHS Markit Kingdom v.2015.