An erupting stratovolcano poses numerous hazards for nearby habitation, but none nearly so terrifying and deadly as the
pyroclastic flow.
Pyroclastic flows, comprised of tons of superheated sulfuric gases, particulate rock materials and ash, can reach temperatures of 1,830 °F and travel at alarming speeds up to 450mph. Convection of materials within the clouds causes them to become a suspension,
fluidizing and
thundering noxiously across the surrounding landscape for miles, in some cases even uphill or across open water. Wherever these clouds come in contact with humans the result is catastrophe, as the residents of
Herculaneum and
St. Pierre, Martinique learned within minutes of the eruptions of Vesuvius in 79AD and Pelee in 1902-- both towns were overwhelmed by pyroclastic clouds, igniting all flammable materials and incinerating and suffocating the inhabitants. None survived
Herculaneum, while just two of
St. Pierre's 26,000 survived, one of whom was a prisoner condemned to death and awaiting his execution in a dungeon cell. Despite their incredible capacity for violence, pyroclastic flows are also capable of producing
mesmerizing,
awe-inspiring beauty.
posted by baphomet
on Feb 18, 2009 -
18 comments
Surtsey was first observed on November 14, 1963, as
a pillar of smoke on the water some ways south of Iceland. The very next day lava and tephra broke the surface of the Atlantic and by May, 1964 the formation had grown to 2.4 km². Over the next three years lava eruptions continued, coating the loose debris in a hard shell and protecting it from erosion.
An island born. Naturally, Surtsey has been under close scientific observation since its emergence, and courtesy
The Surtsey Research Society you can read published reports on the
geology and
biological colonization of this new earth.
posted by carsonb
on Jul 17, 2008 -
9 comments
