The data set contains 13 2D multichannel seismic lines acquired across Poseidon mud volcano chain, Caalbrian Arc, offshore southern Italy. Data were processed onboard during expedition POS515 with R/V POSEIDON. These lines were also recorded on 12 OBS. Details see cruise report (Riedel et al., 2017). Main processing steps include: Geometry definition, Common-Mid-(CMP) Point sorting (1.5625 m bin-space), Normal-Moveout-Corrention (NMO) using a constant velocity of 1500 m/s and Stacking Stolt-Migration (in time) with constant velocity of 1500 m/s. Data processing was completed onboard using the SU processing package. Seismic Surveying at Poseidon mudvlcano started with line P4001 on July 3, 2017 (08:22 am, CET) at 17°40.12'E, 38°21.58N. The last line acquired in this sequence is line P6010. Surveying ended on July 5, 2017 at 04:00 am (CET) at 17°43.12'E, 38°18.96'N.

The data are provided in SEG-Y format. The file names (e.g. P4001_110444_111015.migstolt.1500.1.5625_Amplitudes) contain information about:Line-Number (e.g. Line P4001)Shot-point rage used (e.g. 110444 - 111015)Migration used (Stolt-migration)Bin-size for CMP sorting: 1.5625Data-type: AmplitudesDetails on data acquisition and lines acquired see cruise report (Riedel et al., 2017).Sampling rate: 0.0005 sNumber of samples per trace: 14001 (P4000-P4003); 12001 (P6001-P6010)The following header locations can be used for accessing coordinates:CDP-Number: byte: 21-24CDP-X-bin coordinate: byte 81-84 (in meter UTM, zone 33N, WGS-84)CDP-Y-bin coordinate: byte 85-88 (in meter UTM, zone 33N, WGS-84)Line P4001_110444_111015.migstolt.1500.1.5625_Amplitudes: 6869 traces total;Line P4002_111050_111460.migstolt.1500.1.5625_Amplitudes: 3822 traces total;Line P4003_111520_112575.migstolt.1500.1.5625_Amplitudes: 12220 traces total;Line P6001_115104_115590.migstolt.1500.1.5625_Amplitudes: 3828 traces total;Line P6002_115670_116320.migstolt.1500.1.5625_Amplitudes: 5317 traces total;Line P6003_116440_117040.migstolt.1500.1.5625_Amplitudes: 5544 traces total;Line P6004_117100_117770.migstolt.1500.1.5625_Amplitudes: 6031 traces total;Line P6005_117885_118450.migstolt.1500.1.5625_Amplitudes: 5396 traces total;Line P6006_118600_119205.migstolt.1500.1.5625_Amplitudes: 6017 traces total;Line P6007_119307_119930.migstolt.1500.1.5625_Amplitudes: 5509 traces total;Line P6008_120085_120505.migstolt.1500.1.5625_Amplitudes: 4358 traces total;Line P6009_120550_121080.migstolt.1500.1.5625_Amplitudes: 4818 traces total;Line P6010_121250_121837.migstolt.1500.1.5625_Amplitudes: 5084 traces total;