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Grassfire in Iceland
Title Grassfire in Iceland
Description In western Iceland in late March 2006, a large fire broke out in the grasses of a wetland area, which had been dried out by a period of persistent north winds. According to local reports, some farmers in the area had to evacuate their livestock to protect them from the fast-moving, wind-driven blaze. In this image from the Moderate Resolution Imaging Spectroradiometer (MODIS) [ http://modis.gsfc.nasa.gov ] on NASA's Terra [ http://terra.nasa.gov ] satellite on March 30, 2006, a long plume of smoke blows westward away from the fire, whose location is marked in red in the image. NASA image by Jeff Schmaltz, MODIS Rapid Response Team, [ http://rapidfire.sci.gsfc.nasa.gov ] Goddard Space Flight Center.
Grassfire in Iceland
Title Grassfire in Iceland
Description At the end of March 2006, a grassfire broke out in western Iceland, perhaps as a result of a smoldering cigarette butt. Although this area near the coast to the northwest of the country's capital, Reykjavik, is typically very wet, a period of persistent north winds dried out the grass and made it flammable. The fire burned for several days, threatening farms and livestock and resulting in Iceland's largest fire in its recorded history. This image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov ] on NASA's Terra [ http://terra.nasa.gov ] satellite was captured on April 6, 2006. The burned area appears as a large brownish-charcoal splotch in the center of the image. The fire started inland and burned all the way to the coast. This is a false-color image, and unburned vegetation appears red, clouds appear white, and the Atlantic Ocean (image left) appears nearly black. Several partially ice-covered lakes are scattered across the burned landscape, these lakes appear light blue. NASA image created by Jesse Allen, Earth Observatory, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team [ http://asterweb.jpl.nasa.gov ]
Grimsvotn Volcano Erupts
Title Grimsvotn Volcano Erupts
Description Iceland?s Grimsvotn Volcano began erupting on November 2, 2004, forcing officials to divert air traffic from the region to prevent ash from damaging aircraft engines. The volcano sits beneath the Vatnajokull Ice Cap, Europe?s largest glacier, and is Iceland?s most frequently active volcano. This eruption may be connected to the draining of a glacier lake in the volcano?s caldera. Buried under a 200-meter thick ice shelf, the lake is under extreme pressure. Melting water fills the lake, and when levels are high enough, the water lifts the ice dam, draining the lake. Grimsvotn Lake drained in mid-October, lifting some of the pressure from the volcano. The flood was followed by a series of earthquakes, and on November 2, an eruption. As of November 3, the eruption was still occurring, and ash was reported to have drifted as far northeast as Finland. The Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA?s Terra [ http://terra.nasa.gov/ ] satellite captured this view of the erupting volcano. The plume is largely made of steam rising from the melting ice above the volcano, but ash is mixed in as well. Against the white of the Vatnajokull Ice Cap, the white eruption plume is difficult to see in the true color image. The false color image, which shows ice as bright red, provides the contrast needed to see the steam plume. As the plume is blown north, the steam dissipates, and the dark ash is more visible. The shadow on the snow along the top edge of the image may be ash on the glacier. As the eruption continues, flooding is likely around the volcano. So far, some of the glacier-fed rivers southeast of the volcano have flooded, and more floods are expected. The high-resolution images provided above are at MODIS? maximum resolution of 250 meters per pixel. The MODIS Rapid Response Team provides both the true [ http://rapidfire.sci.gsfc.nasa.gov/gallery/?2004307-1102/Iceland.A2004307.1210 ] and false [ http://rapidfire.sci.gsfc.nasa.gov/gallery/?2004307-1102/Iceland.A2004307.1210.367 ] color images in additional resolutions. NASA images courtesy Jacques Descloitres, MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC
Grimsvotn Volcano Erupts
Title Grimsvotn Volcano Erupts
Description Iceland?s Grimsvotn Volcano began erupting on November 2, 2004, forcing officials to divert air traffic from the region to prevent ash from damaging aircraft engines. The volcano sits beneath the Vatnajokull Ice Cap, Europe?s largest glacier, and is Iceland?s most frequently active volcano. This eruption may be connected to the draining of a glacier lake in the volcano?s caldera. Buried under a 200-meter thick ice shelf, the lake is under extreme pressure. Melting water fills the lake, and when levels are high enough, the water lifts the ice dam, draining the lake. Grimsvotn Lake drained in mid-October, lifting some of the pressure from the volcano. The flood was followed by a series of earthquakes, and on November 2, an eruption. As of November 3, the eruption was still occurring, and ash was reported to have drifted as far northeast as Finland. The Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA?s Terra [ http://terra.nasa.gov/ ] satellite captured this view of the erupting volcano. The plume is largely made of steam rising from the melting ice above the volcano, but ash is mixed in as well. Against the white of the Vatnajokull Ice Cap, the white eruption plume is difficult to see in the true color image. The false color image, which shows ice as bright red, provides the contrast needed to see the steam plume. As the plume is blown north, the steam dissipates, and the dark ash is more visible. The shadow on the snow along the top edge of the image may be ash on the glacier. As the eruption continues, flooding is likely around the volcano. So far, some of the glacier-fed rivers southeast of the volcano have flooded, and more floods are expected. The high-resolution images provided above are at MODIS? maximum resolution of 250 meters per pixel. The MODIS Rapid Response Team provides both the true [ http://rapidfire.sci.gsfc.nasa.gov/gallery/?2004307-1102/Iceland.A2004307.1210 ] and false [ http://rapidfire.sci.gsfc.nasa.gov/gallery/?2004307-1102/Iceland.A2004307.1210.367 ] color images in additional resolutions. NASA images courtesy Jacques Descloitres, MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC
Grimsvotn Volcano Erupts
Title Grimsvotn Volcano Erupts
Description Iceland?s Grimsvotn Volcano began erupting on November 2, 2004, forcing officials to divert air traffic from the region to prevent ash from damaging aircraft engines. The volcano sits beneath the Vatnajokull Ice Cap, Europe?s largest glacier, and is Iceland?s most frequently active volcano. This eruption may be connected to the draining of a glacier lake in the volcano?s caldera. Buried under a 200-meter thick ice shelf, the lake is under extreme pressure. Melting water fills the lake, and when levels are high enough, the water lifts the ice dam, draining the lake. Grimsvotn Lake drained in mid-October, lifting some of the pressure from the volcano. The flood was followed by a series of earthquakes, and on November 2, an eruption. As of November 3, the eruption was still occurring, and ash was reported to have drifted as far northeast as Finland. The Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA?s Terra [ http://terra.nasa.gov/ ] satellite captured this view of the erupting volcano. The plume is largely made of steam rising from the melting ice above the volcano, but ash is mixed in as well. Against the white of the Vatnajokull Ice Cap, the white eruption plume is difficult to see in the true color image. The false color image, which shows ice as bright red, provides the contrast needed to see the steam plume. As the plume is blown north, the steam dissipates, and the dark ash is more visible. The shadow on the snow along the top edge of the image may be ash on the glacier. As the eruption continues, flooding is likely around the volcano. So far, some of the glacier-fed rivers southeast of the volcano have flooded, and more floods are expected. The high-resolution images provided above are at MODIS? maximum resolution of 250 meters per pixel. The MODIS Rapid Response Team provides both the true [ http://rapidfire.sci.gsfc.nasa.gov/gallery/?2004307-1102/Iceland.A2004307.1210 ] and false [ http://rapidfire.sci.gsfc.nasa.gov/gallery/?2004307-1102/Iceland.A2004307.1210.367 ] color images in additional resolutions. NASA images courtesy Jacques Descloitres, MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC
Dust Plumes off Iceland
Title Dust Plumes off Iceland
Description Plumes of dust blew off the southern coast of Iceland in late June 2007. The Moderate Resolution Imaging Spectroradiometer (MODIS) [ http://modis.gsfc.nasa.gov/ ] flying on NASA's Terra [ http://terra.nasa.gov/ ] satellite captured this image on June 23, 2007. The dust appears as grayish blurs emanating from the coast southward over the North Atlantic Ocean. Blue-green algal blooms also fringe the coastline. Iceland's winter of 2006-2007 brought relatively light snow, leaving the local vegetation little shelter from frost. Both the vegetation and soil dried further in two weeks of arid weather prior to this dust storm. Strong winds from the north added the final ingredient needed for dust plumes in late June. You can download a 250-meter-resolution KMZ file of Iceland [ http://earthobservatory.nasa.gov/NaturalHazards/Archive/Jul2007/iceland_tmo_2007174.kmz ] suitable for use with Google Earth. [ http://earth.google.com/ ] NASA image created by Jesse Allen, using data provided courtesy of the MODIS Rapid Response [ http://rapidfire.sci.gsfc.nasa.gov/ ] team. Image interpretation by Ingibjörg Jónsdóttir, University of Iceland.
Dust Storm Off Southern Coas …
Title Dust Storm Off Southern Coast of Iceland
Description The Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA?s Terra satellite, captured this true-color image of Iceland on January 28, 2002. There appear to be large plumes of brownish dust blowing out over the North Atlantic from Iceland?s southern coast. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov/ ] at NASA GSFC
Landslide Buries Valley of t …
Title Landslide Buries Valley of the Geysers
Description Geysers are a rare natural phenomena found only in a few places, such as New Zealand, Iceland, the United States (Yellowstone National Park), and on Russia's far eastern Kamchatka Peninsula. On June 3, 2007, one of these rare geyser fields was severely damaged when a landslide rolled through Russia's Valley of the Geysers. The landslide—a mix of mud, melting snow, trees, and boulders—tore a scar on the land and buried a number of geysers, thermal pools, and waterfalls in the valley. It also blocked the Geyser River, causing a new thermal lake to pool upstream. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER [ http://asterweb.jpl.nasa.gov/ ]) on NASA's Terra [ http://terra.nasa.gov/ ] satellite captured this infrared-enhanced image on June 11, 2007, a week after the slide. The image shows the valley, the landslide, and the new thermal lake. Even in mid-June, just days from the start of summer, the landscape is generally covered in snow, though the geologically heated valley is relatively snow free. The tree-covered hills are red (the color of vegetation in this false-color treatment), providing a strong contrast to the aquamarine water and the gray-brown slide. According to the Russian News and Information Agency (RIA [ http://en.rian.ru/ ]) [English language], the slide left a path roughly a kilometer and a half (one mile) long and 200 meters (600 feet) wide. Within hours of the landslide, the water in the new lake inundated a number of additional geysers. The geysers directly buried under the landslide now lie under as much as 60 meters (180 feet) of material, according to RIA reports. It is unlikely that the geysers will be able to force a new opening through this thick layer, adds RIA. Among those directly buried is Pervenets (Firstborn), the first geyser found in the valley, in 1941. Other geysers, such as the Bolshoi (Greater) and Maly (Lesser) Geysers, were silenced when buried by water building up behind the new natural dam. According to Vladimir and Andrei Leonov of the Russian Federation Institute of Volcanology and Seismology, [ http://www.kscnet.ru/ivs/expeditions/2007/Geyser_Valley-06-2007/Geyser_Valley-06.htm ], the new lake appears to be stable and draining gradually through the earthen dam, alleviating fears of a catastrophic flood. Should the new lake drain enough, many of the inundated geysers may restart. Initial reports from the Volcanology and Seismology Institute state this has already happened for some geysers. Geysers outside of the slide region, including the Velikan (Giant) Geyser and a major section of the geyser field known as Vitrazh (Stained Glass) appear to have escaped damage. In addition to destroying a number of geysers, the landslide may have damaged habitats in the Valley of the Geysers. The thermal waters and heated steam jets made this valley warmer than the surrounding landscape, and the warmth supported a unique ecosystem. The loss of a large part of its heat source may alter the ecosystem, but it is not clear what additional longer-term changes might occur. For example, salmon that spawn in the Geyser River will be confined to the lower reaches of the river, and bears, which depended on salmon, will need to shift feeding grounds correspondingly. Thanks to Sergey Chernomorets and Boris Yurchak for information and translation. You can download a 15-meter-resolution KMZ file of Valley of the Geysers [ http://earthobservatory.nasa.gov/NaturalHazards/Archive/Jun2007/kamgeysers_ast_2007162.kmz ] for use with Google Earth. [ http://earth.google.com/ ] NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.
Low Pressure System off Icel …
Title Low Pressure System off Iceland
Description The MODIS instrument onboard NASA's Terra satellite captured this true-color image of a large low pressure system off the coast of Iceland. In the Northern Hemisphere, the circulation around low pressure systems is counterclockwise and inward, a result of the Coriolis Force. Air flowing inward in low pressure systems has no where to go but up. The rising air cools, and if it rises far enough, clouds and precipitation can form. Image courtesy Jesse Allen, NASA's Earth Observatory based on data provided by the MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov/ ].
Extratropical Cyclones near …
Title Extratropical Cyclones near Iceland
Description A cyclone is a low-pressure area of winds that spiral inwards. Although tropical storms most often come to mind, these spiraling storms can also form at mid- and high latitudes. Two such cyclones formed in tandem in November 2006. The Moderate Resolution Imaging Spectroradiometer (MODIS) [ http://modis.gsfc.nasa.gov/ ] flying onboard NASA's Terra [ http://terra.nasa.gov/ ] satellite took this picture on November 20. This image shows the cyclones south of Iceland. Scotland appears in the lower right. The larger and perhaps stronger cyclone appears in the east, close to Scotland.Cyclones [ http://en.wikipedia.org/wiki/Cyclone ] at high and mid-latitudes are actually fairly common, and they drive much of the Earth's weather. In the Northern Hemisphere, cyclones move in a counter-clockwise direction, and both of the spiraling storms in this image curl upwards toward the northeast then the west. The eastern storm is fed by thick clouds from the north that swoop down toward the storm in a giant "V" shape on either side of Iceland. Skies over Iceland are relatively clear, allowing some of the island to show through. South of the storms, more diffuse cloud cover swirls toward the southeast. NASA image by Jesse Allen, Earth Observatory. Image interpretation provided by Dave Santek and Jeff Key, University of Wisconsin-Madison.
Dust Plumes off Iceland: Nat …
nasa, nasanaturalhazards
Plumes of dust blew off the …
iceland_tmo_2007174
mediatype IMAGE
mediatype image
date 2007-06-23
creator NASA -- NASA Image Of The Day
identifier iceland_tmo_2007174
Landslide Buries Valley of t …
nasa, nasanaturalhazards
Geysers are a rare natural p …
kamgeysers_ast_2007162
mediatype IMAGE
mediatype image
date 2007-06-11
creator NASA -- NASA Image Of The Day
identifier kamgeysers_ast_2007162
Unusual Wildfire in Iceland: …
nasa, nasaimageofthedaygalle …
In western Iceland in late M …
ge_06434
mediatype IMAGE
mediatype image
date 2006-03-30
creator NASA -- NASA image by Jeff Schmaltz, rapidfire.sci.gsfc.nasa.gov MODIS Rapid Response Team, Goddard Space Flight Center.
identifier ge_06434
Reykjavik, Iceland: Image of …
nasa, nasaimageofthedaygalle …
The world's northernmost cap …
ge_07652
mediatype IMAGE
mediatype image
date 2002-05-11
creator NASA -- NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan asterweb.jpl.nasa.gov/ ASTER Science Team.
identifier ge_07652
Reykjavik, Iceland: Image of …
nasa, nasaimageofthedaygalle …
The world's northernmost cap …
ge_07652
mediatype IMAGE
mediatype image
date 2002-05-11
creator NASA -- NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan asterweb.jpl.nasa.gov/ ASTER Science Team.
identifier ge_07652
The Land of Ice and Fire : I …
nasa, nasaimageofthedaygalle …
Due to an unusual combinatio …
iceland_misr_med
mediatype IMAGE
mediatype image
date 2001-08-16
creator NASA -- Image courtesy NASA/GSFC/LaRC/JPL, MISR Team
identifier iceland_misr_med
The Land of Ice and Fire : I …
nasa, nasaimageofthedaygalle …
Due to an unusual combinatio …
iceland_misr_med
mediatype IMAGE
mediatype image
date 2001-08-16
creator NASA -- Image courtesy NASA/GSFC/LaRC/JPL, MISR Team
identifier iceland_misr_med
Grassfire in Iceland: Natura …
nasa, nasanaturalhazards
At the end of March 2006, a …
ge_16352
mediatype IMAGE
mediatype image
date 2006-04-06
creator NASA -- NASA Image Of The Day
identifier ge_16352
Grassfire in Iceland: Natura …
nasa, nasanaturalhazards
At the end of March 2006, a …
ge_16352
mediatype IMAGE
mediatype image
date 2006-04-06
creator NASA -- NASA Image Of The Day
identifier ge_16352
Ireland: Image of the Day
nasa, nasaimageofthedaygalle …
Between 51.5 and 55.5 degree …
Ireland_AMO_2007122
mediatype IMAGE
mediatype image
date 2007-05-02
creator NASA -- NASA image by Jeff Schmaltz, rapidfire.sci.gsfc.nasa.gov MODIS Rapid Response Team, Goddard Space Flight Center.
identifier Ireland_AMO_2007122
Grassfire in Iceland: Natura …
nasa, nasanaturalhazards
In western Iceland in late M …
Iceland.TMO2006089
mediatype IMAGE
mediatype image
date 2006-03-30
creator NASA -- NASA Image Of The Day
identifier Iceland.TMO2006089
Low Pressure System off Icel …
nasa, nasanaturalhazards
The MODIS instrument onboard …
terra_iceland_05jun04
mediatype IMAGE
mediatype image
date 2004-06-05
creator NASA -- NASA Image Of The Day
identifier terra_iceland_05jun04
Landslide Buries Valley of t …
nasa, nasaimageofthedaygalle …
Geysers are a rare natural p …
ge_07789
mediatype IMAGE
mediatype image
date 2007-06-01
creator NASA -- NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.
identifier ge_07789
Landslide Buries Valley of t …
nasa, nasaimageofthedaygalle …
Geysers are a rare natural p …
ge_07789
mediatype IMAGE
mediatype image
date 2007-06-01
creator NASA -- NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.
identifier ge_07789
Extratropical Cyclones near …
nasa, nasaimageofthedaygalle …
A cyclone is a low-pressure …
ge_07264
mediatype IMAGE
mediatype image
date 2006
creator NASA -- NASA image by Jesse Allen, Earth Observatory. Image interpretation provided by Dave Santek and Jeff Key, University of Wisconsin-Madison.
identifier ge_07264
Extratropical Cyclones near …
nasa, nasaimageofthedaygalle …
A cyclone is a low-pressure …
ge_07264
mediatype IMAGE
mediatype image
date 2006
creator NASA -- NASA image by Jesse Allen, Earth Observatory. Image interpretation provided by Dave Santek and Jeff Key, University of Wisconsin-Madison.
identifier ge_07264
Extratropical Cyclones near …
nasa, nasanaturalhazards
A cyclone is a low-pressure …
iceland_tmo_2006324
mediatype IMAGE
mediatype image
date 2006-11-20
creator NASA -- NASA Image Of The Day
identifier iceland_tmo_2006324
Small Volcano in Tempe Terra
PIA01468
Sol (our sun)
Mars Orbiter Camera
Title Small Volcano in Tempe Terra
Original Caption Released with Image (closest point to the planet during the orbit). The local time (on Mars) was late in the afternoon--the Sun was only 10° above the horizon--equivalent to about 5:20 p.m. Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO., Mars is famous for its giant volcanoes, such as Elysium Mons--observed by Mars Global Surveyor in July 1998--and the colossal Olympus Mons--3 times the height of Mt. Everest and as big as the U.S. state of Arizona. However, not all martian volcanoes are large. One of Mars Global Surveyor's most recent pictures, indeed, highlights one of Mars' tiniest volcanoes--a small "shield" volcano with a 2 kilometer (1.2 mile-) long depression at its summit. The small volcano is located in the Tempe-Mareotis Fossae region of Tempe Terra (local context Viking 1 Orbiter image 627a28). Centered at 36.2°N, 85.1°W, this is one of many small volcanoes on Mars. The Mars Global Surveyor MOC image presented here is the first close-up view of one of these small volcanoes. This volcano is similar in both shape and size to many of the small basalt shield volcanoes found on the Snake River Plain in southern Idaho, U.S.A. Other similar volcanic vents are found in Hawaii and Iceland. Basalt is the dark, iron- and magnesium-rich silicate rock found in places like the Snake River Plain, Hawaii, and Iceland. Basalt is also common on the floor of Earth's oceans and on the flat plains of the Moon known as "maria". The volcano seen in this MOC image does not show many of the features generally found around volcanoes of this size on Earth. Instead of the lava flows and leveed channels found on Earth, we see only a faint pattern of subtle, somewhat sinuous ridges and troughs that are radial to the long, elliptical summit depression (or "caldera"). This pattern gives the surface of the volcano and its surroundings quite a rough appearance. Much of the appearance of this "sandpaper-like" texture appears to be unrelated to the volcano, but is instead an expression of the eroded "regolith"--"soil"--that covers the old lava flows. The MOC image suggests that a person hiking around on this small martian volcano would find the walk pretty difficult (especially in a spacesuit). But what an exciting and fascinating walk that would be. Not only would one be able to look, and even hike down, into the 150 m (460 foot) deep caldera, but one could also inspect the spectacular, regularly-spaced ridges seen on the floors of nearby troughs ("e.g.," in the lower 1/3 of this MOC image). These ridges are formed by wind and are probably composed of a mixture of sand and granules--perhaps reworked cinders from ancient volcanic eruptions in the region. Some windblown ridges can also be seen in the shadows on the floor of the volcano's linear caldera. The MOC image was taken at 6:57 a.m. (PDT) on August 22, 1998, during the 506th orbit of Mars Global Surveyor as the spacecraft was nearing its 507th "periapsis"
Small Volcano in Tempe Terra
PIA01468
Sol (our sun)
Mars Orbiter Camera
Title Small Volcano in Tempe Terra
Original Caption Released with Image (closest point to the planet during the orbit). The local time (on Mars) was late in the afternoon--the Sun was only 10° above the horizon--equivalent to about 5:20 p.m. Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO., Mars is famous for its giant volcanoes, such as Elysium Mons--observed by Mars Global Surveyor in July 1998--and the colossal Olympus Mons--3 times the height of Mt. Everest and as big as the U.S. state of Arizona. However, not all martian volcanoes are large. One of Mars Global Surveyor's most recent pictures, indeed, highlights one of Mars' tiniest volcanoes--a small "shield" volcano with a 2 kilometer (1.2 mile-) long depression at its summit. The small volcano is located in the Tempe-Mareotis Fossae region of Tempe Terra (local context Viking 1 Orbiter image 627a28). Centered at 36.2°N, 85.1°W, this is one of many small volcanoes on Mars. The Mars Global Surveyor MOC image presented here is the first close-up view of one of these small volcanoes. This volcano is similar in both shape and size to many of the small basalt shield volcanoes found on the Snake River Plain in southern Idaho, U.S.A. Other similar volcanic vents are found in Hawaii and Iceland. Basalt is the dark, iron- and magnesium-rich silicate rock found in places like the Snake River Plain, Hawaii, and Iceland. Basalt is also common on the floor of Earth's oceans and on the flat plains of the Moon known as "maria". The volcano seen in this MOC image does not show many of the features generally found around volcanoes of this size on Earth. Instead of the lava flows and leveed channels found on Earth, we see only a faint pattern of subtle, somewhat sinuous ridges and troughs that are radial to the long, elliptical summit depression (or "caldera"). This pattern gives the surface of the volcano and its surroundings quite a rough appearance. Much of the appearance of this "sandpaper-like" texture appears to be unrelated to the volcano, but is instead an expression of the eroded "regolith"--"soil"--that covers the old lava flows. The MOC image suggests that a person hiking around on this small martian volcano would find the walk pretty difficult (especially in a spacesuit). But what an exciting and fascinating walk that would be. Not only would one be able to look, and even hike down, into the 150 m (460 foot) deep caldera, but one could also inspect the spectacular, regularly-spaced ridges seen on the floors of nearby troughs ("e.g.," in the lower 1/3 of this MOC image). These ridges are formed by wind and are probably composed of a mixture of sand and granules--perhaps reworked cinders from ancient volcanic eruptions in the region. Some windblown ridges can also be seen in the shadows on the floor of the volcano's linear caldera. The MOC image was taken at 6:57 a.m. (PDT) on August 22, 1998, during the 506th orbit of Mars Global Surveyor as the spacecraft was nearing its 507th "periapsis"
Sand Dunes in Noachis Terra
PIA05293
Sol (our sun)
Mars Orbiter Camera
Title Sand Dunes in Noachis Terra
Original Caption Released with Image 11 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark-toned sand dunes in a crater in eastern Noachis Terra. Most big martian dunes tend to be dark, as opposed to the more familiar light-toned dunes of Earth. This difference is a product of the composition of the dunes, on Earth, most dunes contain abundant quartz. Quartz is usually clear (transparent), though quartz sand grains that have been kicked around by wind usually develop a white, frosty surface. On Mars, the sand is mostly made up of the darker minerals that comprise iron- and magnesium-rich volcanic rocks--i.e., like the black sand beaches found on volcanic islands like Hawaii. Examples of dark sand dunes on Earth are found in central Washington state and Iceland, among other places. This picture is located near 49.0°S, 326.3°W. Sunlight illuminates this scene from the upper left, the image covers an area 3 km (1.9 mi) wide.
The Land of Ice and Fire
PIA03426
Sol (our sun)
Multi-angle Imaging SpectroR …
Title The Land of Ice and Fire
Original Caption Released with Image . Each image represents an area of about 200 by 340 kilometers. Two of Iceland's larger icecaps, Langjökull (located just below image center) and Hofsjökull (just above center) can be clearly seen. The western edge of Vatnajökull is also visible at the top of the image, and a portion of Myrdalsjökull can be seen through the clouds in the upper right. Langjökull (the Long Glacier, 1287 meters maximum elevation)is the second largest icecap in Iceland. It supplies water to Lake Pingvallavatn, the largest lake in the country (visible in the lower right), and to several other lakes and geothermal areas. Hofsjökull (the Temple Glacier, 1760 meters) is the third largest icecap in Iceland. The landscape under the ice is the great mountain mass if of a central subglacial volcano. The brighter, rounded area atop the icecap is a vast, ice filled caldera. The Pjórsá, Iceland's longest and largest river, is fed by the Hofsjökull icecap. The river can be seen running adjacent to the icecap toward the Atlantic Ocean at image right. Iceland has a very vigorous climate, and the high-energy coastline and glacial melt waters result in the movement of a large amount of sediment to the sea, visible herein the turbid waters of the Pjórsá. The capital city of Reykjavík is visible in the lower right as a greyish region along the coast, to the west of (below) a bank of cumulus clouds. Reykjavík is located about 20 kilometers west of the Reykjanes-Langjökull volcanic zone, and the name of the city, the "Bay of Smokes", is testimony to the region's geothermal activity. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology., Due to an unusual combination of tectonic settings, many icecaps and glaciers of Iceland rest above active volcanoes. This landnation is located on the northern edge of the Mid-Atlantic ridge, at the intersection of the North American and Eurasian plates, and is one of the few places on Earth where a mid-ocean ridge is exposed above sea level. The land is built from erupted and intruded magmas concentrated around a hot spot beneath the spreading ridge. These late summer views of central and southwestern Iceland were obtained by the Multi-angle Imaging SpectroRadiometer on August 16,2001, during Terra orbit 8842. The upper image is a true-color view from the instrument's vertical-viewing (nadir) camera. The lower image is a stereo anaglyph generated from the instrument's nadir and 60-degree forward-viewing cameras. Viewing the anaglyph in 3-D requires the use of red/blue glasses with the red filter placed over your left eye. The images have been oriented with north at the left in order to facilitate stereo viewing. Information on ordering glasses is available here [ http://photojournal.jpl.nasa.gov/Help/VendorList.html#Glasses ]
A Vortex Street in the Arcti …
PIA03448
Sol (our sun)
Multi-angle Imaging SpectroR …
Title A Vortex Street in the Arctic
Original Caption Released with Image Marine stratocumulus clouds frequently form parallel rows, or "cloud streets", along the direction of wind flow. When the flow is interrupted by an obstacle such as an island, a series of organized eddies can appear within the cloud layer downwind of the obstacle. These turbulence patterns are known as von Karman vortex streets. In these images from NASA's Multi-angle Imaging SpectroRadiometer, an impressive vortex pattern continues for over three hundred kilometers southward of Jan Mayen island. Jan Mayen is an isolated territory of Norway, located about 650 kilometers northeast of Iceland in the north Atlantic Ocean. Jan Mayen's Beerenberg volcano rises about 2.2 kilometers above the ocean surface, providing a significant impediment to wind flow. These MISR images were captured on June 6, 2001, during Terra orbit 7808. The entire vortex street can be seen in the top panel, which is a natural-color view from the instrument's nadir (downward-looking) camera. The area covered measures 365 kilometers x 158 kilometers, and a cloud-clearing effect is apparent at the vortex centers until finally closing on the sixteenth"hole." The bottom panel is a stereo anaglyph of a portion of the vortex street, compiled using data from MISR's 26-degree forward and 70-degree backward viewing cameras. This view covers an area of about 183 kilometers x 96 kilometers. Despite the vertical exaggeration afforded by using widely separated angles, the relatively modest height variation in the cloud layer implies a vertically stable atmosphere. To facilitate stereo viewing, the images have been oriented with north at the left. Red/blue glasses should be used with the red filter placed over your left eye. Information on ordering glasses can be found here [ http://photojournal.jpl.nasa.gov/Help/VendorList.html#Glasses ]. Fluid dynamicist Theodore von Karman was the first to derive the conditions under which these turbulence patterns occur. Von Karman was a professor of aeronautics at the California Institute of Technology and one of the principal founders of NASA's Jet Propulsion Laboratory. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.
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