The MELT (Mantle ELectromagnetic and Tomography Experiment) is a major field experiment of the RIDGE program. The goal of this experiment is clearer understanding of the mechanisms of generation of oceanic lithosphere at this region of high spreading rates. The combination of seismic and electromagnetic investigations is designed to image upper mantle structure and determine the patterns of melt transport and mantle flow. This experiment made use of 51 Ocean-bottom Seismometers (OBSs) and 47 seafloor magnetometers and electrometers, making it the largest marine geophysics experiment ever performed.
The MELT I cruise deployed 51 Ocean-Bottom Seismometers last year. This cruise (MELT II) is the recovery cruise for the 51 OBSs and the deployment cruise for 47 electromagnetic instruments at 32 sites. The EM instruments will be down for a one-year recording period. The MELT II cruise departed from Papeete, Tahiti, on 17 May, 1996 and returned to San Diego, CA, USA on June 27, 1996.