Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground they remain as tephra unless hot enough to fuse together into pyroclastic rock or tuff. ==Overview== The distribution o...
Materials of all types and sizes that are erupted from a crater or volcanic vent and deposited from the air. 
Materials of all types and sizes that are erupted from a crater or volcanic vent and deposited from the air.
ash and debris ejected by volcano
Materials of all types and sizes that are erupted from a crater or volcanic vent and deposited from the air.
(from the article `pyroclastic flow`) The term tephra as originally defined was a synonym for pyroclastic materials, but it is now used in the more-restricted sense of pyroclastic ...
Tephra erupted by Mount St. Helens on 18 May 1980 ranging in size from ash (left 2 piles) to lapilli (right 2 piles). Credit: D. Wieprecht / U.S. Geological Survey Volcanic ash falls to ground and creates darkness, Mount Pinatubo in the Philippines. Credit: E. Wolfe / U.S. Geological Survey ...
Materials of all types and sizes that are erupted from a crater or volcanic vent and deposited from the air.
A general term for pyroclastic material ejected from a volcano. It includes ash, dust, bombs, and other types of fragments.
Fragmented rock material ejected by a volcanic explosion. Also called pyroclastic material.
Rock fragments and particles ejected by a volcanic eruption.
Any rock material produced by a volcano. 
A general term for all pyroclastic material.