How do you define "volcanic ash"?

Trish

Volcanic ash is material thrown out of a volcano as particles (rather than as a lava flow), and less than 2mm across. General terms for this material that is thrown out as particles include "pyroclastic material" and "tephra". Thus volcanic ash is tephra that is <2mm across. If it is between 2mm and 64mm it is called lapilli, and if itis >64 mm it is called bombs. The word "ash" is kind of an unfortunate choice because volcanic ash doesn't have anything to do with the ash that forms in a fire.

Sincerely,
Scott Rowland

Other Categories Other Questions
To VolcanoWorld