Lava and other materials that are launched from a volcano into the air ate referred to as

Lava and other materials that are launched from a volcano into the air are referred to as TEPHRA.
Tephra refers to fragmental materials that are produced when a volcanic eruption occurs. Tephra can bring about all manner of hazards. The materials that are launched into the atmosphere during volcanic eruption are often electrically charged, thus, they usually produce lighting which is capable of destroying so many things, including killing humans. 

Efficiency is an act of doing something

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