The National Science Foundation has recently started a multiyear study of the Mid-Oceanic Ridge (MOR), with emphasis on the dynamics of axial magmatic, tectonic, and hydrothermal processes [National Academy of Sciences, 1988]. The map on the cover shows the globe-circling MOR and the names of the ridge sections.
Locating sites of active volcanism along the MOR is important to this research. Plate motions (for example, DeMets et al. ) require an average lava volume of 4 km3 yr−1 to be extruded along the approximately 60,000-km MOR system (assuming the average oceanic crust includes 1.3 km of extrusives). To date, however, no MOR volcanism has been observed except where the accreting plate boundary emerges above sea level, in Iceland and the Afar Triangle. By contrast, locating and monitoring terrestrial volcanism by aircraft and satellite is making rapid progress [Mouginis-Mark et al., 1989]