This project will initiate long-term monitoring of the Mid-Atlantic Ridge to characterize the seismicity of this slow-spreading ridge over a wide range of event sizes. The goal is to obtain a first-order understanding of the spatial and temporal patterns in overall seismicity, and the partitioning between magmatic and tectonic events, with the long-term goal of incorporating this information into a model for spreading at the Mid-Atlantic Ridge. Six autonomous underwater hydrophones will be moored within the SOFAR sound channel between 15 degrees and 35 degrees north on the flanks of the Mid-Atlantic Ridge. The array will be deployed for two years.