Where does the lava come from?
Rocks that are moving upward in the mantle beneath Hawai`i begin to melt about 40 to 60 miles (60 to 100 km) depth. The molten rock, called magma , rises because of its relatively low density. The magma “ponds” in a reservoir 1 to 4 miles (2 to 6 km) beneath the summit. The magma can follow fractures up to the crater and produce a summit eruption. During the current eruption, the magma has followed a zone of weakness, the East Rift Zone. Magma reaches the surface at a vent, an opening at the surface through which volcanic material is extruded. There have been several vents during the last 10 years. The currently active vent is 15 miles (24 km) from the summit and 6 miles (9.6 km) above the coast.
