Sediment echosounder data using Atlas Parasound P70 echosounder was recorded during SONNE cruise SO278, which took place between 12.10.2020 to 01.12.2020 bathymetry data based on multibeam echosounder (MBES) was recorded. The main objective of this cruise was to investigate the interactions between the seabed and ocean water in Greek waters, whereby the plate tectonic constellation of a broad collision zone represents a special tectonic drive. Investigations on mud volcanoes were carried out in four working areas: the Sartori mud volcano in the Calabrian Arc, the Cobblestone Area, the Olimpi Mud Volcano Field and the United Nation Ridge.Description of data source:During the SO278 cruise, the hull-mounted parametric sub-bottom profiler ATLAS PARASOUND P70 was used to conduct information about the sediment sub-surface and water column. Its function is based on the parametric effect of the non-linear relation of pressure and density during sonar propagation. The system utilizes two high-intensity waves with frequencies of 18-20 kHz (primary high frequency; PHF) and 22-24 kHz to create a secondary high (about 40-42 kHz) and secondary low frequency (SLF) of about 4 kHz. The SLF can record sub-bottom structures, whereas the PHF can image the water column and potential gas bubbles, plankton ,fish or nepheloid layers within. The transducer array has an opening angle of 4° by 5°, which corresponds to a footprint size of about 7% of the water depth. Data acquisition was performed using measured real-time values of surface sound velocity and a static sound velocity profile of 1500 m/s. Using the software ATLAS PARASTORE, data was displayed and stored as raw .asd files and additional .ps3 and auxiliary files for certain depth windows. The *.ps3 files were utilized for conversion to SEG-Y format and further processing using the software SeNT (developed by V. Spiess & H. Keil, MTU-GeoB) and Kingdom Suite.For further information on the system, consult: https://epic.awi.de/id/eprint/26733/7/ATLAS_PARASOUND_2015-02.pdfThe sub-bottom profiler was operating almost continuously with a desired frequency of 4 kHz for SLF and a desired frequency of 18 kHz for PHF. Most of the time the system run as continuous wave for water column analyisis and simultaneously with the multibeam echosounder and provided the basis for gravity cores and heat flow measurements.Chief Scientist: G. Bohrmann (gbohrmann@marum.de)