The project will use the submersible ALVIN and the AUV SENTRY to obtain samples on-and off-axis at the intermediate-spreading Galapagos Spreading Center to study the effects of variable magma supply on volcanic processes at the intermediate-spreading Galapagos Spreading Center. The project will obtain important new constraints on the relationships between magma supply, magma chamber properties and processes, eruption dynamics and the development of volcanic landforms at this intermediate-spreading mid-ocean ridge.