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Airborne Synthetic Aperture Radar of Alaska and California
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Shaded Relief Mosaic of Umna
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PIA03509
Sol (our sun)
AirSAR
| Title |
Shaded Relief Mosaic of Umnak Island, Aleutian Islands, Alaska |
| Original Caption Released with Image |
This image is a shaded relief mosaic of Umnak Island in Alaska's Aleutian Islands. It was created with Airsar data that was geocoded and combined into this mosaic as part of a NASA-funded Alaska Digital Elevation Model Project at the Alaska Synthetic Aperture Radar Facility (ASF) at the University of Alaska Geophysical Institute in Fairbanks, Alaska. Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena. |
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Perspective View of Umnak Is
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PIA03508
Sol (our sun)
AirSAR
| Title |
Perspective View of Umnak Island, Aleutian Islands, Alaska (#2) |
| Original Caption Released with Image |
This image is a perspective view of Umnak Island, one of Alaska's Aleutian Islands. The active Okmok volcano appears in the center of the island. The image was created by draping a Landsat 7 Thematic Mapper image over a digital elevation mosaic derived from Airsar data. This work was conducted as part of a NASA-funded Alaska Digital Elevation Model Project at the Alaska Synthetic Aperture Radar Facility (ASF) at the University of Alaska Geophysical Institute in Fairbanks, Alaska. Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena. |
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Perspective View of Umnak Is
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PIA03507
Sol (our sun)
AirSAR
| Title |
Perspective View of Umnak Island, Aleutian Islands, Alaska (#1) |
| Original Caption Released with Image |
This image is a perspective view of Umnak Island, one of Alaska's Aleutian Islands. The active Okmok volcano appears in the center of the island. The image was created by draping a Landsat 7 Thematic Mapper image over a digital elevation mosaic derived from Airsar data. This work was conducted as part of a NASA-funded Alaska Digital Elevation Model Project at the Alaska Synthetic Aperture Radar Facility (ASF) at the University of Alaska Geophysical Institute in Fairbanks, Alaska. Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena. |
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Mt. Pinatubo, Phillipines -
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PIA03513
Sol (our sun)
AirSAR
| Title |
Mt. Pinatubo, Phillipines - Comparison of November, 1996 and September, 2000 |
| Original Caption Released with Image |
Built, operated and managed by the Jet Propulsion Laboratory, Pasadena, Calif., AIRSAR is part of NASA's Earth Science Enterprise program. JPL is a division of the California Institute of Technology in Pasadena., The effects of the June 15, 1991, eruption of Mt. Pinatubo continue to affect the lives of people living near the volcano on the island of Luzon in the Philippines. The eruption produced a large amount of volcanic debris that was deposited on the flanks of the volcano as part of pyroclastic flows. This debris consists of unconsolidated ash and boulders, and following heavy rains, it mixes with the rain run-off to form volcanic mudflows called lahars. Lahars are moving rivers of concrete slurry that are highly erosive. They can sweep down existing river valleys, carving deep canyons where the slopes are steep, or depositing a mixture of fine ash and larger rocks on the gentler slopes. The deposits left from a lahar soon solidify into a material similar to concrete, but while they are moving, lahars are dynamic features, and in a single river valley, the active channel may change locations within a few minutes or hours. These changes represent a significant natural hazard to local communities. These images from the NASA's airborne imaging radar AIRSAR instrument show two snapshots in the evolution of the lahars in the lower Pasig-Potrero River, just north of the town of Bacalor, east of the summit of the volcano. These images were collected on November 29, 1996 and September 25, 2000. The radar is particularly good at picking out spatial variations in the average particle size of the lahar deposits, which show up as a variety of different colored units at lower right. The active river channel is dark in both images, and is particularly well-defined in the September 2000 image. In the November 1996 image, the area of the flooded channel is much wider, so that the radar images are quite effective at showing where the drier surface materials are located. Also visible as a series of linear features in both images is a series of concrete dikes that have been constructed to protect the adjacent agricultural land from the lahar deposits. Some of this land has recently been developed as fish ponds, which are visible in the lower left of the 2000 image as a series of small, dark blue rectangles. Scientists have been using airborne radar data collected by NASA's AIRSAR instrument in their studies of the aftereffects of the Mt. Pinatubo eruption. AIRSAR collected imaging radar data over the volcano during a mission to the Pacific Rim region in late 1996 and on a follow-up mission to the area in late 2000. These data sets, along with remote sensing data collected from satellites, provide valuable information about the dynamic landscape and its hazards. AIRSAR collects radar interferometry used to produce digital elevation models. By comparing topographic data collected in 1996 and again in 2000, volcanologists can study how the shape and size of the volcano is changing. The detailed topography is also used to determine the highest risk areas for lahars to flow. AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. |
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Perspective View of Okmok Vo
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PIA03511
Sol (our sun)
AirSAR
| Title |
Perspective View of Okmok Volcano, Aleutian Islands, Alaska (#2) |
| Original Caption Released with Image |
This perspective view shows the caldera of the Okmok volcano in Alaska's Aleutian Islands. The shaded relief was generated from and draped over an Airsar-derived digital elevation mosaic. Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena. |
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Perspective View of Okmok Vo
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PIA03510
Sol (our sun)
AirSAR
| Title |
Perspective View of Okmok Volcano, Aleutian Islands, Alaska (#1) |
| Original Caption Released with Image |
This perspective view shows the caldera of the Okmok volcano in Alaska's Aleutian Islands. The shaded relief was generated from and draped over an Airsar-derived digital elevation mosaic. Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena. |
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Mt. Pinatubo, Phillippines -
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PIA03512
Sol (our sun)
AirSAR
| Title |
Mt. Pinatubo, Phillippines - Perspective View |
| Original Caption Released with Image |
The effects of the June 15, 1991, eruption of Mt. Pinatubo continue to affect the lives of people living near the volcano on the island of Luzon in the Philippines. The eruption produced a large amount of volcanic debris that was deposited on the flanks of the volcano as part of pyroclastic flows. This perspective view looking toward the east shows the western flank of the volcano where most of these pyroclastic flows were deposited. This debris consists of ash and boulders that mix with water after heavy rains to form volcanic mudflows called lahars. Lahars are moving rivers of concrete slurry that are highly erosive. They can sweep down existing river valleys, carving deep canyons where the slopes are steep, or depositing a mixture of fine ash and larger rocks on the gentler slopes. The deposits left from a lahar soon solidify into a material similar to concrete, but while they are moving, lahars are dynamic features, and in a single river valley the active channel may change locations within a few minutes or hours. These changes represent a significant natural hazard to local communities. The topographic data were collected by NASA's airborne imaging radar AIRSAR instrument on November 29, 1996. Colors are from the French SPOT satellite imaging data in both visible and infrared wavelengths collected in February 1996. Areas of vegetation appear red and areas without vegetation appear light blue. River valleys radiate out from the summit of the volcano (upper center). Since the eruption, lahars have stripped these valleys of any vegetation. The Pasig-Potrero River flows to the northeast off the summit in the upper right of the image. Scientists have been using airborne radar data collected by the AIRSAR instrument in their studies of the aftereffects of the Mt. Pinatubo eruption. AIRSAR collected imaging radar data over the volcano during a mission to the Pacific Rim region in late 1996 and on a follow-up mission to the area in late 2000. These data sets along with remote sensing data collected from satellites provide valuable information on the dynamic landscape and the hazards that it poses. AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. Built, operated and managed by the Jet Propulsion Laboratory, Pasadena, Calif., AIRSAR is part of NASA's Earth Science Enterprise program. JPL is a division of the California Institute of Technology in Pasadena. |
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