| Our Earth is covered by volcanoes.
Volcanoes are breaks in the Earth's cool surface where
hot liquid rock from the interior comes out -- sometimes suddenly.
In the above image from the
ASTER camera aboard NASA's orbiting
Terra satellite, snow-capped volcanoes are seen from overhead that compose the
picturesque Islands of the
Four Mountains
in the
Aleutian Islands,
Alaska,
USA.
The islands contain restless
Mt. Cleveland,
an active volcano currently being watched to see if it emits an
ash cloud that could
affect air travel over parts of North America.
A close look at Mt. Cleveland, seen near the image center, shows a red rocky base, a white snow-covered peak,
a light plume of gas and ash, and dark lanes
where ash and debris fell or flowed.
Millions of volcanoes have likely been active over the turbulent history of the Earth's surface, while about 20 volcanoes are
erupting even today, at any given time.
Credit & Copyright:
Earth Observatory,
NASA,
Terra satellite,
ASTER;
Processing by: Jesse Allen & Robert Simmon
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