A subglacial volcano is a volcanic form produced by eruptions beneath a glacier
or beneath the surface of a lake within a glacier.
Eruptions occurring under thick ice (>150 m) such as the 1996 Gjalp eruption beneath Vatnajokull, Iceland, can produce catastrophic floods (jokulhlaups) capable of devastating infrastructure.
The term ‘subglacial eruption’ indicates any eruption which occurs entirely beneath ice, although the erupted material may eventually breach the ice surface.
Examples of Subglacial Volcanoes