The data comprise processed active-source seismic data acquired with ocean bottom seismometers (OBS). The data were collected at Poseidon mud volcano chain during expedition POS515 with the research vessel POSEIDON (Riedel et al., 2017) in the Mediterranean Sea, Calabrian Arc, offshore southern Italy. The entire data set consists of 12 OBS stations. Seismic data were shot across the OBS along 14 2D profiles. Each OBS consist of 4 channels (channel 1: hydrophone; channel 2: horizontal component 1; channel 3: horizontal component 2; channel 4: vertical component).

The data are provided in SEG-Y format.Each uploaded file (608 files in total) consists of the airgun shots recorded with the individual Ocean-Bottom-Seismometers (OBS).Naming convention is as follows using one file p4000_sub4001.obsP01.ch1.sgy as example:p4000: Survey name (from entire POS515 cruise; p4000, p6000)_sub4001: line name (4001, 4002, 4003, 6001, 6002, 6003, 6004, 6005, 6006, 6007, 6008, 6009, 6010)obsP01: OBS-station number (P01, P02, P03, P04, P05, P06, P07, P08, P09, P10, P11, P12)ch1: channel number (1, 2, 3, 4)sgy: data typeEach segy-data file has header-information set that can be used for plotting and analyses:trace-count (tracr, byte : 1)shotpoint number (byte 17-20), as defined for entire cruise POS515 (see cruise report for local shot-point and survey association)shot X coordinate (sx, byte :73-76, coordinate in ArcSec, WGS84, value given with a multiplier of 100)shot Y coordinate (sy, byte: 77-80, coordinate in ArcSec, WGS84, value given with a multiplier of 100)OBS X coordinate (gx, byte: 81-84, coordinate in ArcSec, WGS84, value given with a multiplier of 100)OBS Y coordinate (gy, byte: 85-88, coordinate in ArcSec, WGS84, value given with a multiplier of 100)Survey p4000 was shot with a 10 seconds interval between consecutive shots;Survey p6000 was shot with a 7 seconds interval between consecutive shots;SEG-Y data extracted from survey p4000 have 10001 samples per trace;SEG-Y data extracted from survey p6000 have 7001 samples per trace;Please note: OBS station P01 stopped recording pre-maturely during the survey and did not record shots of lines 'sub6007', 'sub6008', 'sub6009', and 'sub6010'.