The 3D multi channel seismic data were acquired as part of a collaborative investigation into models of magmatic segmentation between the Scripps Institute of Oceanography and BIRPS (the British Institutions Reflection Profiling Syndicate). The 3D EPR (East Pacific Rise) ARAD (Anatomy of a Ridge Axis Discontinuity) EW9707 cruise was undertaken in September and October 1997 to provide both refelction and wide-angle seismic data for the study of the overlapping spreading centre (OSC) at 9 degrees 3 minutes N on the East Pacific Rise. The data were acquired with a single source and a single streamer with a nominal line spacing of 100 m. The 3D-EPR ARAD survey was a joint NERC/NSF (US National Science Foundation) funded project and the copyright for this survey is held jointly. Reference: Bazin, S. Harding, AJ. et al. (2001) Three-dimensional shallow crustal emplacement at the 9 degree 03 minute N overlapping spreading center on the East Pacific Rise, Journal of Geophysical Research.