Definition: An opening, or rupture, in the Earth's surface or crust, which allows hot, molten rock, ash and gases to escape from deep below the surface.
Definition: A tract of alluvium formed at the mouth of a river where the deposition ofsome of its load exceeds its rate of removal, crossed by the divergent channels (distributaries) of the river.
Definition: An opening, or rupture, in the Earth's surface or crust, which allows hot, molten rock, ash and gases to escape from deep below the surface.
