How Does an Observatory Work?
When magma rises through Earth's crust to a mid-ocean ridge, ocean observatory sensors detect the ground motion, the spilling lava, and the chemicals spewing from hydrothermal vents. Observations are relayed via satellite back to shore-based researchers, who can command their instruments and a robotic vehicle to make specialized measurements, and then muster an expedition to inspect the eruption firsthand with submersibles or other undersea vehicles. (Animation by Jack Cook, Woods Hole Oceanographic Institution)