Photo: D.A. Swanson, 4 April 1980, St.Helena, USA

En høy søyle av damp, støv, aske og stein blir blåst flere hundre meter opp i luften.
Denne type utbrudd menes å oppstå når store mengder grunn- eller overflatevann kommer
i kontakt med varm stein eller masse i en vulkansk åpning, og dette blir konstant omdannet
til damp. Denne tar så med seg alt den møter på sin vei opp gjennom åpningen.

Utbruddet på Taal-vulkanen på Philippinene i 1965 var en phreatisk eksplosjon.
The eruption of the Taal-volcano in Philippines in 1965, was a phreatic explosion.


1. An explosion of steam, water, mud, and other material. May result from heating of groundwater
by magma, and may generate base surges.
2. A type of volcanic explosion that occurs when water comes in contact with hot rocks or ash
near a volcanic vent, causing steam explosions.
3. An explosive volcanic eruption caused when water and heated volcanic rocks interact to produce
a violent expulsion of steam and pulverized rocks. Magma is not involved.

The eruption of Taal Volcano in the Philippine Islands in 1965 typifies "Phreatic" (or steam-blast)
behavior. Here, a great column of steam, dust, ash, and cinders is blasted to a height of several
thousand feet. This type of violent eruption is believed to occur when a large quantity of ground
or surface water comes in contact with hot rock or magma in a volcanic vent and is instantly
and explosively flashed to steam.