This information was summarized from Smithsonian Institution's Global Volcanism Program . Cross-section of upper mantle and crust beneath Lopevi, northern Vanuatu volcanic arc. Lopevi is on the Pacific Plate. The lack of earthquakes between 50 and 200 km depth suggests that the subducted plate has broken into two pieces. Magma is generated at a greater depth, relative to the southern Vanuatu volcanic arc.
Rocks melt where the mantle in the asthenosphere is modified by fluids leaving the subducted plate.
Compare to the tectonic setting of Lopevi, northern Vanuatu volcanic arc. Arrows show direction of flowing rocks in the asthenospheric mantle.