Magma Chamber: it is where magma collects below a volcano.

Ring of Fire: the belt of volcanoes that surround the Pacific Ocean.  This belt contains about two-thirds of the worlds active volcanoes.  It is marked by the volcanic chains of Japan, Kamchatka, South Alaska, the Aleutian Islands, the Cascade Range of the U.S. and Canada, Central America, the Andes, New Zealand