
ISS023-E-15142
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Panian Mine, Semirara Island, Philippines: This detailed
astronaut photograph provides a rare cloud-free view of the northern
end of Semirara Island, which is located approximately 280 kilometers
to the south of Manila in the Philippines. The northern part of the
island is dominated by the Panian Coalfield, the largest of three
coalfields on the island. Most of the coal is used for energy
generation in the Philippines, with some exported to India and
China. The Panian coalfield is being mined using open-pit methods.
The rock and soil above the coal layers (or seams) is known as
overburden. Overburden is removed from the pit and heaped into piles,
several of which ring the northern half of the pit. Several of the
dark coal seams are visible along the sunlit southern wall of the pit
(these may be more visible in the larger image version). Plumes of
sediment from the overburden piles enter the Sulu Sea along the
northern and eastern coastline of the island. The Semirara
coalfields formed from 12–23 million years ago along what was then a
coastal plain—similar to the current geologic environment of the
southeastern Gulf Coast of the United States. Organic materials were
deposited in sequences of sandstone and mudstone, which were then
covered by limestones as the environment became progressively more
marine. Over geologic time, increased pressure from the overlying
rocks changed the layers of organic material into coal.
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ISS023-E-15093
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Ice Floes off the Northeastern Tip of Urup Island, Russia:
From space, it is sometimes difficult to tell where land ends and sea
ice begins in the southern Sea of Okhotsk. This is particularly
evident in this detailed astronaut photograph of the northeastern tip
of Urup Island, one of the many islands in the Kuril chain, which
extends from northern Japan to the Kamchatka Peninsula of Russia.
The approximately 120-kilometer-long island extends to the southwest
from the point illustrated in the image; like the other Kuril
Islands, Urup was formed from volcanic processes along the active
subduction boundary between the Pacific and Okhotsk tectonic plates.
The northeastern tip of the island and three small islands to the
northeast are recognizable by their uniform cover of white snow and
shadowing along the northwestern coastlines. Sea ice that formed to
the north in the Sea of Okhotsk has been piled up against the islands
by prevailing northwesterly winds, forming an irregular mass
connecting the islands (image center). The orientation of patchy low
clouds over Urup Island (image lower left) also suggests that
northwesterly winds are present. Smaller ice floes are breaking off
from the main ice mass at gaps between the islands and forming
fingerlike projections of ice fragments that extend to the southeast
(image lower right). Surface winds may be channeled through these
gaps and accelerated, hastening the breakup and movement of ice.
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ISS023-E-22411
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Volcanoes near Usulután, El Salvador: The Pacific coastline of
much of Central America is marked by a line of active and quiescent
volcanoes known to geologists as the Central American Volcanic Arc.
The volcanoes result from the upward movement of magma generated
along the subduction zone between the Cocos and Caribbean tectonic
plates. Frequent earthquakes also occur along the plate boundary.
This astronaut photograph includes four stratovolcanoes—a type of
volcano common in active subduction zones—in El Salvador, near the
midpoint of the Central American Volcanic Arc. While all of the
volcanoes shown here have been active during the Holocene Epoch (from
about 10,000 years ago to the present), only the 2,130-meter-
(6,990-foot-) high San Miguel (also known as Chaparrastique) has been
active during historical times. The most recent activity of San
Miguel was a minor gas and ash emission in 2002. The stratovolcano’s
steep cone shape and well-developed summit crater are evident, along
with dark lava flows. Immediately to the northwest, the truncated
summit of Chinameca Volcano (also known as El Pacayal) is marked by a
two-kilometer- (one-mile-) wide caldera. The caldera formed when a
powerful eruption emptied the volcano’s magma chamber, causing the
chamber’s roof to collapse. Like its neighbor San Miguel, Chinameca’s
slopes host coffee plantations. Moving to the west, the eroded cone
of El Tigre Volcano is visible. El Tigre formed during the
Pleistocene Epoch (1.8 million to about 10,000 years ago), and it is
likely the oldest of the stratovolcanoes in the image. Usulután
Volcano is directly southwest of El Tigre. While the flanks of
Usulután have been dissected by streams, the mountain still retains a
summit crater that is breached on the eastern side. Several urban
areas—recognizable as light gray to white regions contrasting with
green vegetation and tan fallow agricultural fields—are located in
the vicinity of these volcanoes, including the town of Usulután
(lower left) and Santiago de Mara (upper left).
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ISS023-E-27737
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Nevado del Ruiz Volcano, Colombia: 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.
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ISS023-E-32397
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Gulf of Mexico Oil Spill Observed From the International Space
Station: On April 20, 2010, the oil rig Deepwater Horizon
suffered an explosion and sank two days later. Shortly thereafter,
oil began leaking into the Gulf of Mexico from ruptured pipes deep on
the ocean floor. NASA satellites have been tracking the growth of the
oil spill as it has spread towards the northern Gulf Coast. This
detailed astronaut photograph from May 4 provides a different viewing
perspective on the ongoing event. The image is oblique, meaning that
it was taken from a sideways viewing angle from the International
Space Station (ISS), rather than from a “straight down” (or nadir)
view, which is typical of automated satellite sensors. The view in
this image is towards the west; the ISS was located over the eastern
edge of the Gulf of Mexico when the image was taken. The
Mississippi River Delta and nearby Louisiana coast (image top) appear
dark in the sunglint that illuminates most of the image. Sunglint is
caused by sunlight reflecting off the water surface—much like a
mirror—directly back towards the astronaut observer on the Space
Station. The sunglint improves the identification of the oil spill.
Oil on the water smoothes the surface texture, and the mirror-like
reflection of the Sun accentuates the difference between the smooth,
oil-covered water (dark to light gray ) and the rougher water of the
reflective ocean surface (colored silver to white). Wind and water
currents patterns have modified the oil spill’s original shape into
streamers and elongated masses. Among the coastal ecosystems
threatened by the spill are the Chandeleur Islands (image right
center). Other features visible in the image include a solid field
of low cloud cover at the lower left corner of the image. V-shaped
ship or boat wakes are visible in the large image. Wave patterns at
image lower right are most likely caused by tidal effects.
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ISS023-E-28353
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Panorama of Central Andes Mountains, Salar de Arizaro,
Argentina: This panorama was taken by an astronaut looking
southeast across the South American continent when the International
Space Station (ISS) was almost directly over the Atacama Desert near
Chile’s Pacific coast. The high plains (3000–5000 meters, or
13,000–19,000 feet) of the Andes Mountains, also known as the Puna,
appear in the foreground, with a line of young volcanoes (dashed
line) facing the much lower Atacama Desert (1000–2000 m elevation).
Several salt-crusted dry lakes (known as salars in Spanish) occupy
the basins between major thrust faults in the Puna. Salar de Arizaro
(foreground) is the largest of the dry lakes in this view. The
Atlantic Ocean coastline, where Argentina’s capital city of Buenos
Aires sits along the Río de la Plata, is dimly visible at image top
left. Near image center, the transition (solid line) between two
distinct geological zones, the Puna and the Sierras Pampeanas,
creates a striking landscape contrast. Compared to the Puna, the
Sierras Pampeanas mountains are lower in elevation and have fewer
young volcanoes. Sharp-crested ridges are separated by wide, low
valleys in this region. The Salinas Grandes—ephemeral shallow salt
lakes—occupies one of these valleys. The general color change from
reds and browns in the foreground to blues and greens in the upper
part of the image reflects the major climatic regions: the deserts of
the Atacama and Puna versus the grassy plains of central Argentina,
where rainfall is sufficient to promote lush prairie grass, known
locally as the pampas. The Salinas Grandes mark an intermediate,
semiarid region. What accounts for the changes in topography
between the Puna and the Sierras Pameanas? The geology of this part
of the Andes is a result of the eastward subduction of the Nazca
tectonic plate underneath South America. Seismic data suggest that
beneath the Puna, the Nazca Plate is dipping down steeply. Beneath
the Sierras Pampeanas zone, however, the underlying Nazca plate is
almost horizontal. The levelness may be due to the subduction of a
submarine mountain range known as the Juan Fernández Ridge. In the
simplest terms, ridges are topographic highs that are difficult to
stuff down into the subduction zone, and that has profound effects on
the volcanism and structures of the overlying South America plate.
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ISS023-E-29806
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Kata Tjuta (The Olgas), Northern Territory, Australia: Located
in the Northern Territory of Australia, Uluru-Kata Tjuta National
Park hosts some of the world’s most spectacular examples of
inselbergs, or isolated mountains. The most famous of these
inselbergs is Uluru (also known as Ayers Rock). An equally massive
inselberg located approximately 30 kilometers (20 miles) to the
northwest is known as Kata Tjuta. Like Uluru, this is a sacred site
to the native Anangu or Aboriginal people. An English-born explorer
named the highest peak Mount Olga, with the entire grouping of rocks
informally known as “the Olgas.” Mount Olga has a peak elevation of
1,069 meters (3,507 feet) above sea level, making it 206 meters (676
feet) higher than Uluru. In this astronaut photograph, afternoon
sunlight highlights the rounded summits of Kata Tjuta against the
surrounding sandy plains. Sand dunes are visible at image lower left,
while in other areas (image bottom and image right) sediments washed
from the rocks have been anchored by a variety of grasses and bushes
adapted to the arid climate. Green vegetation in the ephemeral stream
channels that drain Kata Tjuta (image top center) provides colorful
contrast with the red rocks and surrounding soils. Large gaps in the
rocks (highlighted by shadows) are thought to be fractures that have
been enlarged due to erosion. Kata Tjuta is comprised of gently
dipping Mount Currie Conglomerate, a sedimentary rock that includes
rounded fragments of other rock types (here, primarily granite with
less abundant basalt and rhyolite in a coarse sandy matrix).
Geologists interpret the Mount Currie Conglomerate as a remnant of a
large fan of material rapidly eroded from mountains uplifted
approximately 550 million years ago. Subsequent burial under younger
sediments consolidated the eroded materials to form the conglomerate
exposed at the surface today.
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ISS023-E-29061
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City Lights at Night along the France-Italy Border: The
brightly lit metropolitan areas of Torino (Italy), Lyon, and
Marseille (both in France) stand out amidst numerous smaller urban
areas in this dramatic astronaut photograph. The image captures the
nighttime appearance of the France-Italy border. The southwestern end
of the Alps Mountains separates the two countries. The island of
Corsica is visible in the Ligurian Sea to the south (image
top). The full moon reflects brightly on the water surface and also
illuminates the tops of low patchy clouds over the border (image
center). This image was taken by an International Space Station (ISS)
astronaut at approximately 11:55 p.m. local time, when the ISS was
located over the France-Belgium border near Luxembourg. Astronauts
orbiting the Earth frequently collect images that include sunglint,
or the mirror-like reflection of sunlight off a water surface.
Sunglint typically lends a bright, or washed out appearance to the
water surface. In clear-sky conditions, reflected light from the Moon
can produce the same effect (moonglint), as illustrated in this
astronaut photograph. The astronaut observer was looking towards the
southeast at an oblique viewing angle at the time the image was
taken; in other words, looking outwards from the ISS, not straight
down towards the Earth.
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ISS023-E-50542
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Vistula River Flooding, Southeastern Poland: This image, taken
by astronauts onboard the International Space Station, shows
widespread flooding along the Vistula River in southeastern Poland. A
major river in Poland, the Vistula originates on the western slopes
of the mountain Barania Góra in the Carpathian Mountains in southern
Poland. The river winds its way northward for 1,047 kilometers (651
miles), through major cities such as Krakow and Warsaw, to Gdansk Bay
on the Baltic Sea. Several towns have been completely or partially
inundated including Gorzyce, Sokolniki, and Trzes'n' in addition to
large numbers of agricultural fields (normally green as visible at
image top and bottom right). While the flooding illustrated here is
extensive, it represents but a small “snapshot” of conditions that
have developed in Eastern Europe over the past one to two
weeks. Spring flooding of rivers is not an uncommon occurrence in
Poland but this event has been described as the most serious flood in
several decades. Severe floods were recorded in 1570, 1584, 1719,
1891, and 1997, with the first records of local embankments for flood
control dating from the thirteenth century. By 1985, 370 rivers in
Poland (including the Vistula) had been completely or partly embanked
along a total length of 9,028 kilometers (5,610 miles) for some
degree of flood mitigation. In the spring of 2010, heavy rains caused
high waters in the Vistula River, first in southern Poland. Hundreds
of thousands of people were evacuated as the river level rose and
broke through waterlogged dikes and embankments. The flood surge then
moved northward through Warsaw, continuing towards the Baltic
Sea.
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ISS023-E-35670
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Mingachevir Reservoir, Azerbaijan: This detailed astronaut
photograph highlights the southern Mingachevir Reservoir in
north-central Azerbaijan. The Mingachevir Reservoir occupies part of
the Kura Basin, a topographic depression located between the Greater
Caucasus Mountains to the northeast and the Lesser Caucasus Mountains
to the southwest. Folded layers of relatively young (less than 5. 3
million years old) sedimentary rock, explosive volcanic products (ash
and tuff), and unconsolidated sediments form the gray hills along the
northern and southern shorelines of the reservoir (image center and
right). Afternoon sun highlights distinctive parallel patterns in the
hills that are the result of water and wind erosion of different rock
layers exposed at the surface. The nearby city of Mingachevir
(left) is split by the Kur River after it passes through the dam and
hydroelectric power station complex at image top center. The current
city was built in support of the hydroelectric power station
constructed as part of the then-Soviet Union’s energy infrastructure
for the region. Today, Mingachevir is the fourth-largest city in
Azerbaijan (by population), and it has become a cultural and economic
center of the country. The reservoir held approximately 15 billion
cubic meters of water at the time this image was taken, with a total
engineered capacity of 16 billion cubic meters. The width of the
reservoir illustrated here is approximately 8 kilometers (5 miles); a
jet flying over the reservoir left a contrail midway between the
shorelines.
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