"Have you ever dropped a stick in a river and wondered where it might go if it floated all the way downstream? Now you can trace its journey using Streamer
." In addition to displaying the distance traveled, difference in elevation, and number of states, counties and cities the stick will pass through before reaching its outlet point, Streamer can do an upstream trace to show you which rivers and smaller streams fed into the spot where the stick was dropped. [more inside]
posted by Rykey
on Aug 28, 2013 -
First noticed by westerners in 1965, when the Gemini-4 spacecraft flew over northwest Africa
(alternate source, with link to uncompressed TIF
| in Earth photographs from Gemini III, IV, and V
on Archive.org), the Richat Structure
in the Sahara desert of west–central Mauritania
resembles an impact crater or a circular target (or a possible Atlantis
, or Plato's circular city
, or maybe an open-pit mine
), but is a naturally occurring 40-50 km (25-30 mi) geologic dome that has eroded over time
. It's large enough that, when seen in person
, the scale of the geography is hard to capture
. But it is quite impressive
when seen from space
posted by filthy light thief
on Feb 12, 2013 -
Ron Blakey makes paleogeographic maps of the ancient world.
The paleogeographic maps show the varied landscapes of the ancient Earth through hundreds of millions of years of geologic time, including distribution of ancient shallow seas, deep ocean basins, mountain ranges, coastal plains, and continental interiors. Tectonic features shown include subduction zones, island arcs, mid-ocean ridges and accreting terranes.
posted by zamboni
on Dec 5, 2012 -
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
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 -
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 -
(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 -