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
More than 16,000 photos related to the USGS from the years 1868 through 1992 are now available online where they may be easily searched, viewed, and downloaded free of charge.
These are old stereo pairs, sites drowned by dams, geologists and surveyers in horse drawn wagons, petroglyphs, national parks, Mount St. Helens, John Wesley
Powell, hoodoos, arches, ruins, mines...
posted by the Real Dan
on Apr 14, 2005 -
16 comments
GEODE (Geo-Data Explorer) is a free service offered by the U.S. Geological Survey.
It allows the user to retrieve, display, and manipulate multiple types of information, such as satellite images, geologic maps, graphics, live camera feed, three-dimensional images, and spreadsheet data.
posted by thatwhichfalls
on Jan 28, 2004 -
1 comment
