The data set comprise processed active-source seismic data collected with ocean bottom seismometer (OBS). The seismic shots were recorded in the trench outerrise region of the subduction zone off Costa Rica during the expedition JC228 of the research vessel RRS JAMES COOK in December 2022 and January 2023. The data set consists of 36 OBS stations deployed at an interval of 3.5 to 7 km receiving shots of a tuned 5000 cubi-inch airgun array, fired at 90 s interval. The seismic line is a 250 km long West-East trending profile covering the incoming oceanic plate and the Costa Rican deep sea trench. Each OBS consists 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 (reduced with 6 km/s and recording time starting at -1 s). Each uploaded file (144 files in total) consists of the airgun shots recorded with the individual Ocean-Bottom-Seismometers (OBS).The naming convention is as follows using one file p200.obs264.1.sgy as an example:p200: profile name of JC228 surveyobs264: OBS-station number (from 228 to 264)1: 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)shot X coordinate (sx, byte :73-76, coordinate: latitude x 360000)shot Y coordinate (sy, byte: 77-80, coordinate: longitude x 360000)OBS X coordinate (gx, byte: 81-84, coordinate: latitude x 360000)OBS Y coordinate (gy, byte: 85-88, oordinate: longitude x 360000)Shot point navigation (latitude, longitude, shot_number): JC228_p200e_shot_navigation.datOBS coordinates (latitude, longitude, obs_number): JC228_p200e_obs_locations.dat