portions of magma escape and reach the surface to form lava
rapid eruption may follow if the magma begins to de-gas
shallow reservoir is then partially emptied by the eruptions
withdrawing support from the roof of the reservoir.
of the roof of the reservoir causes the formation of the caldera.
of the magma still trapped beneath the caldera may then be
erupted on the floor or along the walls of the caldera. The
caldera may fill with water forming a lake and the new lava
domes can typically form islands as in Lake Taupo and Lake