The SCREECH program was funded by U.S. National Science Foundation (NSF) grant OCE-9819053, the Danish Research Foundation (Danmarks Grundforskningsfond), and the Natural Science and Engineering Council of Canada. D. Shillington was also supported by NSF grant OCE-0241940 and the University of Wyoming Graduate School. B. Tucholke acknowledges support by the Henry Bryant Bigelow Chair in Oceanography at Woods Hole Oceanographic Institution. We thank the ships' officers and crew, scientists, technicians, and students who helped to conduct the seismic experiment during Oceanus Cruise 359-2 and Maurice Ewing Cruise 00-07. We also thank J.-C. Sibuet and Bob Whitmarsh for their helpful comments on the manuscript. This is Woods Hole Oceanographic Institution Contribution No. 11,103.