 Sketch of a magma reservoir beneath a volcano and a conduit leading up to a lava dome at the surface. Arrow indicates direction of magma movement from a deeper source. |
Magma Magma is molten or partially molten rock beneath the Earth's surface. When magma erupts onto the surface, it is called lava . Magma typically consists of (1) a liquid portion (often referred to as the melt); (2) a solid portion made of minerals that crystallized directly from the melt; (3) solid rocks incorporated into the magma from along the conduit or reservoir, called xenoliths or inclusions; and (4) dissolved gases. |
 Lava moves across the ground as a pahoehoe flow, Kilauea Volcano, Hawaii |
Lava Lava is the word for magma (molten rock) when it erupts onto the Earth's surface. Geologists also use the word to describe the solidified deposits of lava flows and fragments hurled into the air by explosive eruptions (for example, lava bombs or blocks). Lava is from the Italian word for stream, which is derived from the verb lavare--to wash. |