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MISR View of Liquefaction Ef
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On January 26, 2001, a magni
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4/26/01
| Date |
4/26/01 |
| Description |
On January 26, 2001, a magnitude 7.7 earthquake devastated the Kachchh region in the Gujarat province of western India, killing 20,000 people and destroying buildings, dams and port facilities. These images from NASA's Multi-angle Imaging SpectroRadiometer (MISR) show the affected area. The two upper MISR images are pre- and post-earthquake scenes acquired on January 15 (left) and January 31, 2001 (right). They are "true-color" images made by combining the red, green and blue bands from MISR's nadir (vertically down-looking) camera. The two lower views are "false-color" images made by combining the red bands from three different cameras. Blue is assigned to the camera pointing 70 degrees forward (more sun-facing), green is assigned to the nadir camera and red is assigned to the camera pointing 70 degrees aftward. The earthquake epicenter was just below the southern tip of the large, white area on the right-hand side of the images, about 70 kilometers (43 miles) northeast of the city of Bhuj. The earthquake may have occurred on the Kachchh Mainland fault, which extends from the region of the epicenter westward along the curved boundary between the darker brown region to the south and the lighter brown area north of it. The compressive stresses responsible for the earthquake are related to the ancient collision of India with Asia and the resulting rise of the Himalayas to the northeast. That part of the Kachchh region that lies north of the Kachchh Mainland fault includes the Banni Plains and the Rann of Kachchh. It is a low, flat basin characterized by salt pans and mud flats. The salt forms in the Rann of Kachchh as mineral-laden waters evaporate. The salt flats can be seen in the nadir images as highly reflective white and gray areas. During the earthquake, strong shaking produced liquefaction in the fine silts and sands below the water table in the Rann of Kachchh. The shaking caused the mineral grains to settle, squeezing the water out from between the grains and forcing it to the surface. Field investigations have found abundant evidence of mud volcanoes, sand boils and fissures from which salty ground water erupted over an area exceeding 10,000 square kilometers (3,860 square miles). Evidence of the expelled water can also be seen on the MISR images. Delicate, dendritic patterns of stream channels run throughout many of the salt flats on the post-earthquake image, especially due north of the epicenter. These channels carried water brought to the surface by liquefaction during the earthquake. Areas where shallow surface water is present are much easier to see on the "false-color" multi-angle composite images. Wet areas exhibit a combination of enhanced forward- scattered light due to the reflection by the water, and enhanced backward scattering due to surface roughness or the presence of sediments. This combination results in blue to purple hues. The region of sand dunes in the upper right and the Indus River valley and delta in the upper left are inside Pakistan. Near the top of the images, an east-west trending linear feature separates the Thar desert of Pakistan from the Rann of Kachchh. This is the Nagar Parkar Fault. On both pre- earthquake images, this feature is evident only from the contrasting brown colors on either side of it. On the post- earthquake images, a narrow ribbon defines the boundary between the two geologic provinces. However, only in the "false-color" image do we see evidence that this ribbon may be a water-filled channel. Because this area is politically sensitive and fairly inaccessible, no field teams have been able to verify liquefaction effects or the presence of water there. MISR, built and managed by NASA's Jet Propulsion Laboratory, is one of several Earth-observing experiments aboard Terra, which was launched in December 1999. JPL is a division of the California Institute of Technology, Pasadena, Calif. Image credit: NASA/GSFC/LaRC/JPL, MISR Team. |
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Liquefaction Effects from th
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| Title |
Liquefaction Effects from the Bhuj Earthquake |
| Description |
These Multi-angle Imaging Spectroradiometer (MISR) images show the Kachchh region in the Gujarat province of western India. On January 26, 2001, a magnitude 7.7 earthquake devastated this area, killing 20,000 people and destroying buildings, dams, and port facilities. The two upper MISR images are pre- and post-earthquake scenes acquired on January 15 and January 31, 2001, respectively. They are "true-color" images made by combining the red, green and blue bands from the nadir (vertically down-looking) camera. The two lower views are "false-color" images made by combining the red bands from three different cameras. Blue is assigned to the camera pointing 70 degrees forward (more sun-facing), green to the nadir camera, and red to the camera pointing 70 degrees aftward. Each of these images is about 275 kilometers wide by 218 kilometers high. The earthquake epicenter was just below the southern tip of the large, white area on the right-hand side of the images, and about 70 kilometers northeast of the city of Bhuj. The earthquake may have occurred on the Kachchh Mainland Fault, which extends from the region of the epicenter westward along the curved boundary between the darker brown region to the south and the lighter brown area north of it. The compressive stresses responsible for the earthquake are related to the collision of India with Asia and the resulting rise of the Himalayas to the northeast. That part of the Kachchh region which lies north of the Kachchh Mainland Fault includes the Banni Plains and the Rann of Kachchh. It is a low, flat basin characterized by salt pans and mud flats. The salt forms in the Rann of Kachchh as mineral-laden waters evaporate. The salt flats can be seen in the nadir images as highly reflective, white and gray areas. During the earthquake, strong shaking produced liquefaction in the fine silts and sands below the water table in the Rann of Kachchh. This caused the mineral grains to settle and expel their interstitial water to the surface. Field investigations have found abundant evidence of mud volcanos, sand boils, and fissures from which salty ground water erupted over an area exceeding 10,000 square kilometers. Evidence of the expelled water can also be seen on the MISR images. Notice the delicate, dendritic pattern of stream channels throughout many of the salt-flats on the post-earthquake image, especially due north of the epicenter. These carried water brought to the surface by liquefaction during the earthquake. Areas where shallow surface water is present are much easier to see on the false-color multi-angle composite images. Wet areas are exhibiting a combination of enhanced forward-scattered light due to the reflection by the water, and enhanced backward scattering due to surface roughness or the presence of sediments. This combination results in blue to purple hues. The region of sand dunes in the upper right and the Indus River valley and delta in the upper left are inside Pakistan. Near the top, of the images, there is an east-west trending linear feature separating the Thar desert of Pakistan from the Rann of Kachchh. This is the Nagar Parkar Fault. On both pre-earthquake images, this feature is evident only from the contrasting brown colors on either side of it. On the post-earthquake images, a narrow ribbon defines the boundary between the two geologic provinces. However, only in the multi-angle composite do we see evidence that this ribbon may be a water-filled channel. Because this area is politically sensitive and fairly inaccessible, no field teams have been able to verify liquefaction effects or the presence of water there. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://www-misr.jpl.nasa.gov/ ] |
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Western Tibet, Shaded Relief
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PIA04969
Sol (our sun)
C-Band Radar, X-Band Radar
| Title |
Western Tibet, Shaded Relief with Color as Height |
| Original Caption Released with Image |
. This shaded relief with color as height image was generated using topographic data from the Shuttle Radar Topography Mission (SRTM) 3-arcsecond (90-meter, 300 feet) data and from the GTOPO30 data (30 arcseconds, 900 meters, 3000 feet spacing). Elevations vary from about 200 meters (600 feet) in purple shades above sea level in the plains of India to over 7700 meters (25,000 feet) in the Himalayas (white) within this image. Radar data used in this research were acquired by the European Remotes Sensing (ERS) satellites operated by the European Space Agency, which kindly made this data available for research. Research was performed at the Centre for the Observation and Modelling of Earthquakes and Tectonics supported by the U.K. Natural Environment Research Council. Part of this research was performed at the Jet Propulsion Laboratory, California Institute of Technology under contract with the U.S. National Aeronautics and Space Administration. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000, and the GTOPO30 data produced by the U.S. Geological Survey Eros Data Center. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Geospatial-Intelligence Agency (NGA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, DC. Size: Image width 320 kilometers (200 miles) and height 850 kilometers (530 miles) Location: 35 degrees North latitude, 79 degrees East longitude at center Orientation: North is up, Universal Transverse Mercator projection, zone 44 Resolution: pixel size is 80 x 80 meters (262 x 262 feet) Date Acquired: February 2000 (SRTM), The 5000 meter (16,000 feet) high Tibetan Plateau has been formed by the collision of the Indian subcontinent with central Asia. The topography rises from the Indus-Ganges plains across the Himalayas and into the lower relief central part of the plateau. The north edge of the plateau is the Altyn Tagh and Kun Lun mountain range. North of Tibet is the Takla Makan desert. Two major faults in western Tibet stand out in the topography and satellite imagery. The Karakoram Fault is the straight line running from top left to lower right across this image, through the Karakoram mountains and southern Tibet. The Altyn Tagh Fault is the slightly curved line running along the northern edge of the plateau from top left to top right. Geologist s and geophysicists have long argued about how fast these two faults in western Tibet are moving. In one model, the Tibetan plateau is like a watermelon seed sliding out to the east along these two faults. In another model, Tibet is deforming internally without sliding rapidly sideways. Scientists at the Centre for Observation and Modelling of Earthquakes and Tectonics and at NASA's Jet Propulsion Lab have used interferometric analysis of radar data from the European Remote Sensing satellites and topographic data from the Shuttle Radar Topography Mission to study the faults in western Tibet. The interferometric analysis was performed with software developed at JPL. The results show that the faults in western Tibet, especially the Karakoram Fault, cannot be moving rapidly. This rules out the watermelon seed "extrusion"http://photojournal.jpl.nasa.gov/catalog/PIA04969 model, at least for western Tibet. These results are published in the journal Science, Volume 305, Issue 5681, pages 236-239, July 9, 2004, available at (subscription required for full text): http://www.sciencemag.org/ [ http://photojournal.jpl.nasa.gov/catalog/PIA04969 http://www.sciencemag.org/ ] |
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Indus Vallis
PIA09990
Sol (our sun)
Thermal Emission Imaging Sys
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| Title |
Indus Vallis |
| Original Caption Released with Image |
Context image for PIA09990 Indus Vallis The major Martian dust storm of 2007 filled the sky with dust and produced conditions that prevented the THEMIS VIS camera from being able to image the surface. With no new images being acquired, we've dug into the archive to highlight some interesting areas on Mars. The this week's topic is medium sized channels. The entire region surrounding Indus Vallis has undergone extensive erosion. The deepest part of the channel is still identifiable, but it is impossible to tell if the wider bounding walls represent a terraced portion of the original channel or just easily eroded materials. Image information: VIS instrument. Latitude 19.0N, Longitude 38.7E. 19 meter/pixel resolution. Please see the THEMIS Data Citation Note [ http://themis.la.asu.edu/terms ] for details on crediting THEMIS images. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena. |
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Indus Vallis
PIA09990
Sol (our sun)
Thermal Emission Imaging Sys
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| Title |
Indus Vallis |
| Original Caption Released with Image |
Context image for PIA09990 Indus Vallis The major Martian dust storm of 2007 filled the sky with dust and produced conditions that prevented the THEMIS VIS camera from being able to image the surface. With no new images being acquired, we've dug into the archive to highlight some interesting areas on Mars. The this week's topic is medium sized channels. The entire region surrounding Indus Vallis has undergone extensive erosion. The deepest part of the channel is still identifiable, but it is impossible to tell if the wider bounding walls represent a terraced portion of the original channel or just easily eroded materials. Image information: VIS instrument. Latitude 19.0N, Longitude 38.7E. 19 meter/pixel resolution. Please see the THEMIS Data Citation Note [ http://themis.la.asu.edu/terms ] for details on crediting THEMIS images. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena. |
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SRTM Radar Image with Color
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PIA02799
Sol (our sun)
C-Band Interferometric Radar
| Title |
SRTM Radar Image with Color as Height: Kachchh, Gujarat, India |
| Original Caption Released with Image |
This image shows the area around the January 26, 2001, earthquake in western India, the deadliest in the country's history with some 20,000 fatalities. The epicenter of the magnitude 7.6 earthquake was just to the left of the center of the image. The Gulf of Kachchh (or Kutch) is the black area running from the lower left corner towards the center of the image. The city of Bhuj is in the yellow-toned area among the brown hills left of the image center and is the historical capital of the Kachchh region. Bhuj and many other towns and cities nearby were almost completely destroyed by the shaking of the earthquake. These hills reach up to 500 meters (1,500 feet) elevation. The city of Ahmedabad, capital of Gujarat state, is the radar-bright area next to the right side of the image. Several buildings in Ahmedabad were also destroyed by the earthquake. The dark blue areas around the center of the image and extending to the left side are low-lying salt flats called the Rann of Kachchh with the Little Rann just to the right of the image center. The bumpy area north of the Rann (green and yellow colors) is a large area of sand dunes in Pakistan. A branch of the Indus River used to flow through the area on the left side of this image, but it was diverted by a previous large earthquake that struck this area in 1819. This image combines two types of data from the Shuttle Radar Topography Mission(SRTM). The image brightness corresponds to the strength of the radar signal reflected from the ground, while colors show the elevation as measured by SRTM. Colors range from blue at the lowest elevations to brown and white at the highest elevations. This image is a mosaic of four SRTM swaths. This image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington DC. Size: 450 by 300 kilometers (280 by 190 miles) Location: 23.5 deg. North lat., 70.5 deg. East lon. Orientation: North up Original Data Resolution: SRTM 30 meters (99 feet) Date Acquired: four days in February, 2000 |
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SRTM Radar Image with Color
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PIA02799
Sol (our sun)
C-Band Interferometric Radar
| Title |
SRTM Radar Image with Color as Height: Kachchh, Gujarat, India |
| Original Caption Released with Image |
This image shows the area around the January 26, 2001, earthquake in western India, the deadliest in the country's history with some 20,000 fatalities. The epicenter of the magnitude 7.6 earthquake was just to the left of the center of the image. The Gulf of Kachchh (or Kutch) is the black area running from the lower left corner towards the center of the image. The city of Bhuj is in the yellow-toned area among the brown hills left of the image center and is the historical capital of the Kachchh region. Bhuj and many other towns and cities nearby were almost completely destroyed by the shaking of the earthquake. These hills reach up to 500 meters (1,500 feet) elevation. The city of Ahmedabad, capital of Gujarat state, is the radar-bright area next to the right side of the image. Several buildings in Ahmedabad were also destroyed by the earthquake. The dark blue areas around the center of the image and extending to the left side are low-lying salt flats called the Rann of Kachchh with the Little Rann just to the right of the image center. The bumpy area north of the Rann (green and yellow colors) is a large area of sand dunes in Pakistan. A branch of the Indus River used to flow through the area on the left side of this image, but it was diverted by a previous large earthquake that struck this area in 1819. This image combines two types of data from the Shuttle Radar Topography Mission(SRTM). The image brightness corresponds to the strength of the radar signal reflected from the ground, while colors show the elevation as measured by SRTM. Colors range from blue at the lowest elevations to brown and white at the highest elevations. This image is a mosaic of four SRTM swaths. This image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington DC. Size: 450 by 300 kilometers (280 by 190 miles) Location: 23.5 deg. North lat., 70.5 deg. East lon. Orientation: North up Original Data Resolution: SRTM 30 meters (99 feet) Date Acquired: four days in February, 2000 |
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Liquefaction Effects from th
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PIA03403
Sol (our sun)
Multi-angle Imaging SpectroR
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| Title |
Liquefaction Effects from the Bhuj earthquake |
| Original Caption Released with Image |
These MISR images show the Kachchh region in the Gujarat province of western India. On January 26, 2001, a magnitude 7.7 earthquake devastated this area, killing 20,000 people and destroying buildings, dams, and port facilities. The two upper MISR images are pre- and post-earthquake scenes acquired on January 15 and January 31, 2001, respectively (Terra orbits 5736 and 5969). They are "true-color" images made by combining the red, green and blue bands from the nadir (vertically down-looking) camera. The two lower views are "false-color" images made by combining the red bands from three different cameras. Blue is assigned to the camera pointing 70 degrees forward (more sun-facing), green to the nadir camera, and red to the camera pointing 70 degrees aftward. Each of these images is about 275 kilometers wide by 218 kilometers high. The earthquake epicenter was just below the southern tip of the large, white area on the right-hand side of the images, and about 70 kilometers northeast of the city of Bhuj. The earthquake may have occurred on the Kachchh Mainland Fault, which extends from the region of the epicenter westward along the curved boundary between the darker brown region to the south and the lighter brown area north of it. The compressive stresses responsible for the earthquake are related to the collision of India with Asia and the resulting rise of the Himalayas to the northeast. That part of the Kachchh region which lies north of the Kachchh Mainland Fault includes the Banni Plains and the Rann of Kachchh. It is a low, flat basin characterized by salt pans and mud flats. The salt forms in the Rann of Kachchh as mineral-laden waters evaporate. The salt flats can be seen in the nadir images as highly reflective, white and gray areas. During the earthquake, strong shaking produced liquefaction in the fine silts and sands below the water table in the Rann of Kachchh. This caused the mineral grains to settle and expel their interstitial water to the surface. Field investigations have found abundant evidence of mud volcanos, sand boils, and fissures from which salty ground water erupted over an area exceeding 10,000 square kilometers. Evidence of the expelled water can also be seen on the MISR images. Notice the delicate, dendritic pattern of stream channels throughout many of the salt-flats on the post-earthquake image, especially due north of the epicenter. These carried water brought to the surface by liquefaction during the earthquake. Areas where shallow surface water is present are much easier to see on the false-color multi-angle composite images. Wet areas are exhibiting a combination of enhanced forward-scattered light due to the reflection by the water, and enhanced backward scattering due to surface roughness or the presence of sediments. This combination results in blue to purple hues. The region of sand dunes in the upper right and the Indus River valley and delta in the upper left are inside Pakistan. Near the top of the, images, there is an east-west trending linear feature separating the Thar desert of Pakistan from the Rann of Kachchh. This is the Nagar Parkar Fault. On both pre-earthquake images, this feature is evident only from the contrasting brown colors on either side of it. On the post-earthquake images, a narrow ribbon defines the boundary between the two geologic provinces. However, only in the multi-angle composite do we see evidence that this ribbon may be a water-filled channel. Because this area is politically sensitive and fairly inaccessible, no field teams have been able to verify liquefaction effects or the presence of water there. 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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