9402622 Filloux This experiment is designed to provide direct observational constraints on the distribution of melt and the pattern of upwelling beneath a mid-ocean ridge. Studies of electromagnetic and seismic wave propagation in the mantle with arrays of ocean- bottom instruments will furnish measurements that can be inverted to find horizontal and vertical variations in velocity and conductivity structure that can be used to test theoretical models of flow. 56 seafloor electromagnetic instruments will be deployed for one year at 17 degrees south on the East Pacific Rise. ***