A new view of ridge segmentation and near-axis volcanism at the East Pacific Rise, 8°-12°N, from EM300 multibeam bathymetry

Abstract

New, high-resolution bathymetry for the East Pacific Rise between 8°N and 12°N was collected over a 6 km wide swath centered on the ridge axis using the 30 kHz Simrad EM300 multibeam system. The coverage area corresponds latitudinally to the designated Ridge2000 Integrated Studies Site (ISS) for fast spreading ridges. The EM300 data, gridded at 30 m latitude by 50 m longitude, represent a greater than 4X improvement in horizontal resolution over previously available multibeam data and a 2X improvement in depth resolution. The new bathymetry was used to update the locations and hierarchy of ridge offsets for this area. Among the many applications for this data, it enables us to tabulate volcanoes half the size that could be previously detected. The distribution of near-axis volcanic cones >25 m high suggests that this population of small, near-axis cones results from low effusion rate eruptions of the ridge axis. Components: 4480 words, 5 figures, 1 table, 1 animation. Copyright 2006 by the American Geophysical Union.