Nevado del Ruiz Volcano (image center) is located approximately 140
kilometers (87 miles) to the northwest of Colombia’s capital, Bogotá.
Covering over 200 square kilometers (77 square miles), Nevado del Ruiz
is a large stratovolcano—a
cone-shaped volcano built from successive layers of lava, ash, and pyroclastic
flow deposits. The volcano is fed by magma generated above the
boundary between the subducting Nazca and overriding South American
tectonic plates. The historical record of eruptions at the volcano
extends back to 1570, but the most damaging eruption in recent times
took place in 1985.
On the November 13, 1985, an explosive eruption at the Arenas Crater
(image center) melted ice and snow at the summit of the volcano.
Mudflows (lahars) swept tens of kilometers down river valleys along the
volcano’s flanks, killing at least 23,000 people. Most of the fatalities
occurred in the town of Armero which was completely inundated by
lahars. Eruptive activity at Nevado del Ruiz may have occurred in 1994,
but this is not confirmed.
The volcano’s summit and upper flanks are covered by several glaciers
that appear as a white mass surrounding the 1-kilometer- (0.6-mile-)
wide Arenas Crater; meltwater from these glaciers has incised the gray
to tan ash and pyroclastic flow deposits mantling the lower slopes. A
well-defined lava flow is visible at image lower right. This astronaut
photograph was taken at approximately 7:45 a.m. local time, when the Sun
was still fairly low above the horizon, leading to shadowing to the
west of topographic high points.
Astronaut photograph ISS023-E-27737
was acquired on April 23, 2010, with a Nikon D3S digital camera fitted
with an 800 mm lens, and is provided by the ISS Crew Earth Observations
experiment and Image Science & Analysis Laboratory, Johnson Space
Center. The image was taken by the Expedition
23 crew. The image in this article has been cropped and enhanced to
improve contrast. Lens artifacts have been removed. The International
Space Station Program supports the laboratory as part of the ISS
National Lab to help astronauts take pictures of Earth that will be
of the greatest value to scientists and the public, and to make those
images freely available on the Internet. Additional images taken by
astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of
Earth. Caption by William L. Stefanov, NASA-JSC.