Interesting facts about volcanism
- Phreatomagmatic refers to the interaction of water with juvenile magma, whereas phreatic or steam explosions simply involving hot rocks and water, and although magmatic heat is likely the source of the thermal energy in the reaction, the deposits do not contain juvenile magmatic material. Source
- Juvenile magma implies that there is an active source of eruptable magma nearing/reaching the surface. Old “magma” is really rock – the solidified lava or conduit material from previous eruptions. If the volcano is merely producing steam-driven eruptions of old material, then there is less likelihood of a large eruption until juvenile magma is seen in the ash or as lava flows/domes at the vent.
(Eric Klemetti, Volcanologist, Denison University. Comment on Eruptions!)
Contributions by Anmarie96 (ATS) acknowledged.