Today we returned to West Mata for the second dive of this expedition to explore in more detail and collect additional samples. It was two years ago at this site that we observed actively erupting volcanic vent sites, Hades and Prometheus. When the ROV reached the ocean floor, we saw sands, rocky fragments and talus shoots, and in-place pillow lavas. We observed the rim of the new Hades pit and now have evidence that strongly suggest that the pit was formed by collapse due to shut off of the magma supply, rather than an explosive crater-forming event. We also observed rubble, fresh pillow lavas, and steep remnant volcanic crags colonized by large numbers of shrimp. Evidence of slope failure was also seen, along with in-place young pillow lava overlying older rock. Vertical dikes, breccia pipes and horizontal lava flows gave us a first rate “cut-away” view of the inside of a volcanic vent complex. Lava samples, water and sediment samples, and shrimp were collected.