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Earthquake Raises Reefs in t
…
| Title |
Earthquake Raises Reefs in the Solomon Islands |
| Description |
When people talk about change happening on a geologic time scale, most of the time, they mean that the change happens over the course of millions of years: the Colorado River gradually cuts through the soft rock of the Colorado Plateau until it has made a 4,000-foot-deep chasm, the Grand Canyon, continents drift centimeters at a time, slowly changing the shape and position of landmasses on the Earth. Most of the time, change is slow, but sometimes, geologic change happens all at once. This was the case on Ranongga Island in the Solomon Islands. In the early morning hours of April 2, 2007, a magnitude 8.1 earthquake shook the Solomon Islands, its epicenter southwest of Ranongga Island. The huge quake pushed much of the island up, raising the coral reefs that ringed the island above the water. In the course of a few minutes, Ranongga Island acquired several meters of new beach. The newly exposed reef forms a gray rim along the eastern shore of the island in the left image, acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on April 12, 2007. In the right image, taken on March 31, 2006, the shallowly submerged reefs color the water a lighter shade of blue. The uplift may be more dramatic than the images show. When ASTER took the 2007 image, the tide was 29.4 centimeters higher than it was when the 2006 image was taken, and yet the uplift is still visible. The lush vegetation that covers the tropical island is bright red in this image, which is made from both visible and infrared light. Out of its aquatic environment, the reef died, becoming the foundation of new land. Such evolution is common in earthquake zones in the Pacific and Indian Oceans. During the December 26, 2004, earthquake that generated the massive Indian Ocean tsunami, Simeulue Island was lifted as much as 150 centimeters (4.9 feet), exposing the reef that surrounded it. A similar set of exposed fossilized reefs on the shores of Papua New Guinea, near the Solomon Islands, provided proof that wobbles in the Earth's orbit trigger ice ages. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. [ http://asterweb.jpl.nasa.gov/ ]Thanks to Aron Meltzner, California Institute of Technology, for help with image interpretation. |
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Earthquake Raises Reefs in t
…
| Title |
Earthquake Raises Reefs in the Solomon Islands |
| Description |
When people talk about change happening on a geologic time scale, most of the time, they mean that the change happens over the course of millions of years: the Colorado River gradually cuts through the soft rock of the Colorado Plateau until it has made a 4,000-foot-deep chasm, the Grand Canyon, continents drift centimeters at a time, slowly changing the shape and position of landmasses on the Earth. Most of the time, change is slow, but sometimes, geologic change happens all at once. This was the case on Ranongga Island in the Solomon Islands. In the early morning hours of April 2, 2007, a magnitude 8.1 earthquake shook the Solomon Islands, its epicenter southwest of Ranongga Island. The huge quake pushed much of the island up, raising the coral reefs that ringed the island above the water. In the course of a few minutes, Ranongga Island acquired several meters of new beach. The newly exposed reef forms a gray rim along the eastern shore of the island in the left image, acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on April 12, 2007. In the right image, taken on March 31, 2006, the shallowly submerged reefs color the water a lighter shade of blue. The uplift may be more dramatic than the images show. When ASTER took the 2007 image, the tide was 29.4 centimeters higher than it was when the 2006 image was taken, and yet the uplift is still visible. The lush vegetation that covers the tropical island is bright red in this image, which is made from both visible and infrared light. Out of its aquatic environment, the reef died, becoming the foundation of new land. Such evolution is common in earthquake zones in the Pacific and Indian Oceans. During the December 26, 2004, earthquake that generated the massive Indian Ocean tsunami, Simeulue Island was lifted as much as 150 centimeters (4.9 feet), exposing the reef that surrounded it. A similar set of exposed fossilized reefs on the shores of Papua New Guinea, near the Solomon Islands, provided proof that wobbles in the Earth's orbit trigger ice ages. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. [ http://asterweb.jpl.nasa.gov/ ]Thanks to Aron Meltzner, California Institute of Technology, for help with image interpretation. |
|
Earthquake Raises Reefs in t
…
| Title |
Earthquake Raises Reefs in the Solomon Islands |
| Description |
When people talk about change happening on a geologic time scale, most of the time, they mean that the change happens over the course of millions of years: the Colorado River gradually cuts through the soft rock of the Colorado Plateau until it has made a 4,000-foot-deep chasm, the Grand Canyon, continents drift centimeters at a time, slowly changing the shape and position of landmasses on the Earth. Most of the time, change is slow, but sometimes, geologic change happens all at once. This was the case on Ranongga Island in the Solomon Islands. In the early morning hours of April 2, 2007, a magnitude 8.1 earthquake shook the Solomon Islands, its epicenter southwest of Ranongga Island. The huge quake pushed much of the island up, raising the coral reefs that ringed the island above the water. In the course of a few minutes, Ranongga Island acquired several meters of new beach. The newly exposed reef forms a gray rim along the eastern shore of the island in the left image, acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on April 12, 2007. In the right image, taken on March 31, 2006, the shallowly submerged reefs color the water a lighter shade of blue. The uplift may be more dramatic than the images show. When ASTER took the 2007 image, the tide was 29.4 centimeters higher than it was when the 2006 image was taken, and yet the uplift is still visible. The lush vegetation that covers the tropical island is bright red in this image, which is made from both visible and infrared light. Out of its aquatic environment, the reef died, becoming the foundation of new land. Such evolution is common in earthquake zones in the Pacific and Indian Oceans. During the December 26, 2004, earthquake that generated the massive Indian Ocean tsunami, Simeulue Island was lifted as much as 150 centimeters (4.9 feet), exposing the reef that surrounded it. A similar set of exposed fossilized reefs on the shores of Papua New Guinea, near the Solomon Islands, provided proof that wobbles in the Earth's orbit trigger ice ages. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. [ http://asterweb.jpl.nasa.gov/ ]Thanks to Aron Meltzner, California Institute of Technology, for help with image interpretation. |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
On December 26, 2004, tsunamis swept across the Indian ocean, spawned by a magnitude 9.0 earthquake off the coast of Sumatra. Aside from Indonesia, the island nation of Sri Lanka likely suffered the most casualties, with the death toll reported at 21,715 on December 29th.DigitalGlobe?s [ http://www.digitalglobe.com/ ] Quickbird satellite captured an image of the devestation around Kalutara, Sri Lanka (top), on December 26, 2004, at 10:20 a.m. local time?about an hour after the first in the series of waves hit. [A Quickbird image taken on January 1, 2004 (lower), shows the normal ocean conditions.] Water is flowing out of the inundated area and back into the sea, creating turbulence offshore. Some near-shore streets and yards are covered with muddy water. It is possible that the image was acquired in a ?trough? between wave crests. Imagery of nearby beaches shows that the edge of the ocean had receded about 150 meters from the shoreline.More images [ http://www.digitalglobe.com/tsunami_gallery.html ] are available on the DigitalGlobe web site. Images Copyright DigitalGlobe [ http://www.digitalglobe.com/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
On December 26, 2004, tsunamis swept across the Indian ocean, spawned by a magnitude 9.0 earthquake off the coast of Sumatra. Aside from Indonesia, the island nation of Sri Lanka likely suffered the most casualties, with the death toll reported at 21,715 on December 29th.DigitalGlobe?s [ http://www.digitalglobe.com/ ] Quickbird satellite captured an image of the devestation around Kalutara, Sri Lanka (top), on December 26, 2004, at 10:20 a.m. local time?about an hour after the first in the series of waves hit. [A Quickbird image taken on January 1, 2004 (lower), shows the normal ocean conditions.] Water is flowing out of the inundated area and back into the sea, creating turbulence offshore. Some near-shore streets and yards are covered with muddy water. It is possible that the image was acquired in a ?trough? between wave crests. Imagery of nearby beaches shows that the edge of the ocean had receded about 150 meters from the shoreline.More images [ http://www.digitalglobe.com/tsunami_gallery.html ] are available on the DigitalGlobe web site. Images Copyright DigitalGlobe [ http://www.digitalglobe.com/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
On December 26, 2004, tsunamis swept across the Indian ocean, spawned by a magnitude 9.0 earthquake off the coast of Sumatra. Aside from Indonesia, the island nation of Sri Lanka likely suffered the most casualties, with the death toll reported at 21,715 on December 29th.DigitalGlobe?s [ http://www.digitalglobe.com/ ] Quickbird satellite captured an image of the devestation around Kalutara, Sri Lanka (top), on December 26, 2004, at 10:20 a.m. local time?about an hour after the first in the series of waves hit. [A Quickbird image taken on January 1, 2004 (lower), shows the normal ocean conditions.] Water is flowing out of the inundated area and back into the sea, creating turbulence offshore. Some near-shore streets and yards are covered with muddy water. It is possible that the image was acquired in a ?trough? between wave crests. Imagery of nearby beaches shows that the edge of the ocean had receded about 150 meters from the shoreline.More images [ http://www.digitalglobe.com/tsunami_gallery.html ] are available on the DigitalGlobe web site. Images Copyright DigitalGlobe [ http://www.digitalglobe.com/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
On December 26, 2004, tsunamis swept across the Indian ocean, spawned by a magnitude 9.0 earthquake off the coast of Sumatra. Aside from Indonesia, the island nation of Sri Lanka likely suffered the most casualties, with the death toll reported at 21,715 on December 29th.DigitalGlobe?s [ http://www.digitalglobe.com/ ] Quickbird satellite captured an image of the devestation around Kalutara, Sri Lanka (top), on December 26, 2004, at 10:20 a.m. local time?about an hour after the first in the series of waves hit. [A Quickbird image taken on January 1, 2004 (lower), shows the normal ocean conditions.] Water is flowing out of the inundated area and back into the sea, creating turbulence offshore. Some near-shore streets and yards are covered with muddy water. It is possible that the image was acquired in a ?trough? between wave crests. Imagery of nearby beaches shows that the edge of the ocean had receded about 150 meters from the shoreline.More images [ http://www.digitalglobe.com/tsunami_gallery.html ] are available on the DigitalGlobe web site. Images Copyright DigitalGlobe [ http://www.digitalglobe.com/ ] |
|
Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
On December 26, 2004, tsunamis swept across the Indian ocean, spawned by a magnitude 9.0 earthquake off the coast of Sumatra. Aside from Indonesia, the island nation of Sri Lanka likely suffered the most casualties, with the death toll reported at 21,715 on December 29th.DigitalGlobe?s [ http://www.digitalglobe.com/ ] Quickbird satellite captured an image of the devestation around Kalutara, Sri Lanka (top), on December 26, 2004, at 10:20 a.m. local time?about an hour after the first in the series of waves hit. [A Quickbird image taken on January 1, 2004 (lower), shows the normal ocean conditions.] Water is flowing out of the inundated area and back into the sea, creating turbulence offshore. Some near-shore streets and yards are covered with muddy water. It is possible that the image was acquired in a ?trough? between wave crests. Imagery of nearby beaches shows that the edge of the ocean had receded about 150 meters from the shoreline.More images [ http://www.digitalglobe.com/tsunami_gallery.html ] are available on the DigitalGlobe web site. Images Copyright DigitalGlobe [ http://www.digitalglobe.com/ ] |
|
Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
On December 26, 2004, tsunamis swept across the Indian ocean, spawned by a magnitude 9.0 earthquake off the coast of Sumatra. Aside from Indonesia, the island nation of Sri Lanka likely suffered the most casualties, with the death toll reported at 21,715 on December 29th.DigitalGlobe?s [ http://www.digitalglobe.com/ ] Quickbird satellite captured an image of the devestation around Kalutara, Sri Lanka (top), on December 26, 2004, at 10:20 a.m. local time?about an hour after the first in the series of waves hit. [A Quickbird image taken on January 1, 2004 (lower), shows the normal ocean conditions.] Water is flowing out of the inundated area and back into the sea, creating turbulence offshore. Some near-shore streets and yards are covered with muddy water. It is possible that the image was acquired in a ?trough? between wave crests. Imagery of nearby beaches shows that the edge of the ocean had receded about 150 meters from the shoreline.More images [ http://www.digitalglobe.com/tsunami_gallery.html ] are available on the DigitalGlobe web site. Images Copyright DigitalGlobe [ http://www.digitalglobe.com/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
Large earthquakes often cause permanent movement of the Earth?s surface, a result of the motion that occurs deep underground. The tsunamis spawned by the magnitude 9.0 earthquake on December 26, 2004, were the result of motions of the sea floor above the earthquake fault. Seismic measurements and computer models show that the Burma Plate slipped up to 20 meters (66 feet) at the location of the earthquake, 18 kilometers underground. The sea floor above moved less, up to 5 meters (16 feet) vertically and 11 meters (36 feet) horizontally. The maps above show estimates of how much the Earth moved as a result of the quake. These calculations are the result of a computer simulation that was based on data from a global network of seismic instruments. A black star marks the earthquake epicenter. On the left is vertical displacement, or uplift. Positive values (red, yellow, and green) show areas that rose during the earthquake, and negative values (blue) show regions that dropped. The maximum rise, along the subduction zone where the Burma Plate is moving over the India Plate, was over 5 meters (16 feet). Along the western edge of Sumatra, the calculations predict the land dropped a maximum of one meter (3.3 feet). This may have moved portions of the coastline permanently below sea level. On the right is horizontal motion. The greatest motion on the sea floor was 11 meters (36 feet). The coast of Sumatra moved as much as 3 meters (9.8 feet), and the north end of Simeulue Island moved 2 meters (6.6 feet). Geologists hope to use remote sensing data, combined with on-site GPS measurements, to evaluate the motion predicted by these computer models. Images courtesy Chen Ji, California Institute of Technology Seismological Laboratory [ http://www.seismolab.caltech.edu/index.html ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
The beaches of Khao Lak, Thailand were struck by a tsunami 2-3 hours after the magnitude 9.0 earthquake of December 26, 2004. Although 500 km away from the epicenter, the waves were 10 meters (33 feet) high. A resort area popular with Northern European tourists, luxury resorts dotted the coastline (January 3, 2003 image, lower center). Buildings and vegetation were scoured by the waves, leaving foundations and bare soil. Beach sand was also removed by the tsunamis. These high-resolution satellite images were acquired by Space Imaging?s [ http://www.spaceimaging.com/ ] Ikonos satellite. Images copyright Space Imaging. [ http://www.spaceimaging.com/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
The beaches of Khao Lak, Thailand were struck by a tsunami 2-3 hours after the magnitude 9.0 earthquake of December 26, 2004. Although 500 km away from the epicenter, the waves were 10 meters (33 feet) high. A resort area popular with Northern European tourists, luxury resorts dotted the coastline (January 3, 2003 image, lower center). Buildings and vegetation were scoured by the waves, leaving foundations and bare soil. Beach sand was also removed by the tsunamis. These high-resolution satellite images were acquired by Space Imaging?s [ http://www.spaceimaging.com/ ] Ikonos satellite. Images copyright Space Imaging. [ http://www.spaceimaging.com/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
The Indonesian province of Aceh was hit hardest by the earthquake and tsunamis of December 26, 2004. Aceh is located on the northern tip of the island of Sumatra. Early Western media attention was focused on Sri Lanka and Thailand, even though the earthquake epicenter was closer to Aceh, and the largest waves struck the northwestern coast of Sumatra. On Decemebr 29, estimates of the death toll in Indonesia were over 80,000—more than half the global total. The town of Lhoknga, on the west coast of Sumatra near the capital of Aceh, Banda Aceh, was completely destroyed by the tsunami, with the exception of the mosque in the city's center. These high-resolution satellite images, acquired by Space Imaging's [ http://www.spaceimaging.com/ ] Ikonos satellite, show Lhoknga before (lower) and after (top) the earthquake and Tsunami. Almost all the trees, vegetation, and buildings in the area were washed away. Behind the town, low-lying agricultural areas remained covered with water 4 days after the disaster, and sand on the nearby beaches was completely removed. The wave height [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12645 ] might have exceeded 15 meters (50 feet) when it struck the shore. Equivalent devestation extends 225 km southeast along the Sumatran Coast, in a band up to 3 km (1.9 miles) deep. Imagery from the Moderate Resolution Imaging Spectroradiometer [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12644 ] (above) shows the affected area as a thin strip of brown along the coast. Ikonos images copyright Centre for Remote Imaging, Sensing and Processing, [ http://www.crisp.nus.edu.sg/ ] National University of Singapore and Space Imaging. [ http://www.spaceimaging.com/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
The Indonesian province of Aceh was hit hardest by the earthquake and tsunamis of December 26, 2004. Aceh is located on the northern tip of the island of Sumatra. Early Western media attention was focused on Sri Lanka and Thailand, even though the earthquake epicenter was closer to Aceh, and the largest waves struck the northwestern coast of Sumatra. On Decemebr 29, estimates of the death toll in Indonesia were over 80,000—more than half the global total. The town of Lhoknga, on the west coast of Sumatra near the capital of Aceh, Banda Aceh, was completely destroyed by the tsunami, with the exception of the mosque in the city's center. These high-resolution satellite images, acquired by Space Imaging's [ http://www.spaceimaging.com/ ] Ikonos satellite, show Lhoknga before (lower) and after (top) the earthquake and Tsunami. Almost all the trees, vegetation, and buildings in the area were washed away. Behind the town, low-lying agricultural areas remained covered with water 4 days after the disaster, and sand on the nearby beaches was completely removed. The wave height [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12645 ] might have exceeded 15 meters (50 feet) when it struck the shore. Equivalent devestation extends 225 km southeast along the Sumatran Coast, in a band up to 3 km (1.9 miles) deep. Imagery from the Moderate Resolution Imaging Spectroradiometer [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12644 ] (above) shows the affected area as a thin strip of brown along the coast. Ikonos images copyright Centre for Remote Imaging, Sensing and Processing, [ http://www.crisp.nus.edu.sg/ ] National University of Singapore and Space Imaging. [ http://www.spaceimaging.com/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
The Indonesian province of Aceh was hit hardest by the earthquake and tsunamis of December 26, 2004. Aceh is located on the northern tip of the island of Sumatra. Early Western media attention was focused on Sri Lanka and Thailand, even though the earthquake epicenter was closer to Aceh, and the largest waves struck the northwestern coast of Sumatra. On Decemebr 29, estimates of the death toll in Indonesia were over 80,000—more than half the global total. The town of Lhoknga, on the west coast of Sumatra near the capital of Aceh, Banda Aceh, was completely destroyed by the tsunami, with the exception of the mosque in the city's center. These high-resolution satellite images, acquired by Space Imaging's [ http://www.spaceimaging.com/ ] Ikonos satellite, show Lhoknga before (lower) and after (top) the earthquake and Tsunami. Almost all the trees, vegetation, and buildings in the area were washed away. Behind the town, low-lying agricultural areas remained covered with water 4 days after the disaster, and sand on the nearby beaches was completely removed. The wave height [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12645 ] might have exceeded 15 meters (50 feet) when it struck the shore. Equivalent devestation extends 225 km southeast along the Sumatran Coast, in a band up to 3 km (1.9 miles) deep. Imagery from the Moderate Resolution Imaging Spectroradiometer [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12644 ] (above) shows the affected area as a thin strip of brown along the coast. Ikonos images copyright Centre for Remote Imaging, Sensing and Processing, [ http://www.crisp.nus.edu.sg/ ] National University of Singapore and Space Imaging. [ http://www.spaceimaging.com/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
The Indonesian province of Aceh was hit hardest by the earthquake and tsunamis of December 26, 2004. Aceh is located on the northern tip of the island of Sumatra. Early Western media attention was focused on Sri Lanka and Thailand, even though the earthquake epicenter was closer to Aceh, and the largest waves struck the northwestern coast of Sumatra. On Decemebr 29, estimates of the death toll in Indonesia were over 80,000—more than half the global total. The town of Lhoknga, on the west coast of Sumatra near the capital of Aceh, Banda Aceh, was completely destroyed by the tsunami, with the exception of the mosque in the city's center. These high-resolution satellite images, acquired by Space Imaging's [ http://www.spaceimaging.com/ ] Ikonos satellite, show Lhoknga before (lower) and after (top) the earthquake and Tsunami. Almost all the trees, vegetation, and buildings in the area were washed away. Behind the town, low-lying agricultural areas remained covered with water 4 days after the disaster, and sand on the nearby beaches was completely removed. The wave height [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12645 ] might have exceeded 15 meters (50 feet) when it struck the shore. Equivalent devestation extends 225 km southeast along the Sumatran Coast, in a band up to 3 km (1.9 miles) deep. Imagery from the Moderate Resolution Imaging Spectroradiometer [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12644 ] (above) shows the affected area as a thin strip of brown along the coast. Ikonos images copyright Centre for Remote Imaging, Sensing and Processing, [ http://www.crisp.nus.edu.sg/ ] National University of Singapore and Space Imaging. [ http://www.spaceimaging.com/ ] |
|
Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
The Indonesian province of Aceh was hit hardest by the earthquake and tsunamis of December 26, 2004. Aceh is located on the northern tip of the island of Sumatra. Early Western media attention was focused on Sri Lanka and Thailand, even though the earthquake epicenter was closer to Aceh, and the largest waves struck the northwestern coast of Sumatra. On Decemebr 29, estimates of the death toll in Indonesia were over 80,000—more than half the global total. The town of Lhoknga, on the west coast of Sumatra near the capital of Aceh, Banda Aceh, was completely destroyed by the tsunami, with the exception of the mosque in the city's center. These high-resolution satellite images, acquired by Space Imaging's [ http://www.spaceimaging.com/ ] Ikonos satellite, show Lhoknga before (lower) and after (top) the earthquake and Tsunami. Almost all the trees, vegetation, and buildings in the area were washed away. Behind the town, low-lying agricultural areas remained covered with water 4 days after the disaster, and sand on the nearby beaches was completely removed. The wave height [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12645 ] might have exceeded 15 meters (50 feet) when it struck the shore. Equivalent devestation extends 225 km southeast along the Sumatran Coast, in a band up to 3 km (1.9 miles) deep. Imagery from the Moderate Resolution Imaging Spectroradiometer [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12644 ] (above) shows the affected area as a thin strip of brown along the coast. Ikonos images copyright Centre for Remote Imaging, Sensing and Processing, [ http://www.crisp.nus.edu.sg/ ] National University of Singapore and Space Imaging. [ http://www.spaceimaging.com/ ] |
|
Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
The Indonesian province of Aceh was hit hardest by the earthquake and tsunamis of December 26, 2004. Aceh is located on the northern tip of the island of Sumatra. Early Western media attention was focused on Sri Lanka and Thailand, even though the earthquake epicenter was closer to Aceh, and the largest waves struck the northwestern coast of Sumatra. On Decemebr 29, estimates of the death toll in Indonesia were over 80,000—more than half the global total. The town of Lhoknga, on the west coast of Sumatra near the capital of Aceh, Banda Aceh, was completely destroyed by the tsunami, with the exception of the mosque in the city's center. These high-resolution satellite images, acquired by Space Imaging's [ http://www.spaceimaging.com/ ] Ikonos satellite, show Lhoknga before (lower) and after (top) the earthquake and Tsunami. Almost all the trees, vegetation, and buildings in the area were washed away. Behind the town, low-lying agricultural areas remained covered with water 4 days after the disaster, and sand on the nearby beaches was completely removed. The wave height [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12645 ] might have exceeded 15 meters (50 feet) when it struck the shore. Equivalent devestation extends 225 km southeast along the Sumatran Coast, in a band up to 3 km (1.9 miles) deep. Imagery from the Moderate Resolution Imaging Spectroradiometer [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12644 ] (above) shows the affected area as a thin strip of brown along the coast. Ikonos images copyright Centre for Remote Imaging, Sensing and Processing, [ http://www.crisp.nus.edu.sg/ ] National University of Singapore and Space Imaging. [ http://www.spaceimaging.com/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
After the deadly tsunamis generated by the December 26, 2004, earthquake near Sumatra devastated the island of Sri Lanka off the southeastern tip of India, the waves continued westward and slammed into southeastern India, along a stretch of coastline called the Coromandel Coast. Cities, towns, and fishing villages up and down the coast of the state of Tamil Nadu were victims of the waves. This image from the Ikonos satellite shows the city of Chennai, a harbor city on the southeastern Indian coast, located about 350 kilometers north of the Palk Strait, which separates Sri Lanka and India. The background image was captured on December 29, 2004, after the waves? arrival. Although the devastation captured in this image may not seem as obvious as the damage to Sri Lanka [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12643 ], parts of Thailand [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12648 ], or northern Sumatra, [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12647 ] a careful eye can see the impacts. Two areas of damage have been cut away and shown at full resolution, in a comparison with imagery from August 14, 2002. Near the top of the image, a stretch of houses or other structures has been wiped out. Where the houses used to be is an open expanse of beach. Near the bottom of the image, boats that were neatly lined up in their moorings along three piers in the August 14 image are piled on top of the piers in the image from December 29. In the large image, other impacts are evident: sand and debris across roads, for example, and dramatic changes in the shape and size of some beaches. Images copyright Space Imaging. [ http://www.spaceimaging.com/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
The Earth?s solid surface floats on a layer of softer rock as a collection of interlocking, movable puzzle pieces called tectonic plates. At 7:58 a.m. (local time), on December 26, 2004, beneath the Indian Ocean west of Sumatra, Indonesia, pent-up energy from the compressional forces of one tectonic plate grinding under another found a weak spot in the overlying rock. The rock was thrust upward, and the Earth shook as a 9.0 magnitude earthquake sent its vibrations out into the ocean. Tsunamis spread out in all directions, the massive waves washed over islands and crashed against coastlines in Sri Lanka, Southern India, and even the east coast of Africa. Tens of thousands of people were killed, millions are homeless. The image above shows how the tectonic puzzle pieces fit together around Indonesia. The epicenter of the recent quake is marked with a red star in the image. It is located just to the east of the Sunda Trench, where the India Plate begins to get subducted beneath (forced under) the Burma Plate. The blue arrows along the plate boundary show the direction of subduction. As the India Plate slides beneath the Burma Plate, it meets pockets of resistance, which causes compressional forces to build up. Weakened overlying rock gets forced upward. Based on the location of aftershocks (red shaded circles on the image), the United States Geological Survey reports that approximately 1,200 kilometers of the plate boundary probably slipped as a result of the quake. The initial rupture was likely more than 100 kilometers wide, and probably produced an average vertical displacement along the fault plane (the slope along which the two plates meet) of 15 meters. When the bottom of the ocean is deformed by this type of ?megathrust? quake, the upward force acts like a fist rising up from underwater. Water rolls down off the sides of the ?fist,? creating massive waves that can travel as fast as an airplane. The waves can move across the ocean and barely disturb the surface, but when they reach shallow coastal water, the earthquake?s energy thrusts them tens of meters into the air. The tsunami created by this earthquake reached India and Sri Lanka in about four hours. The wave eventually reached Africa, the Pacific Ocean, Hawaii, and the west coast of North and South America. For more information about this earthquake and plate tectonics, visit the Website of the USGS. [ http://earthquake.usgs.gov/eqinthenews/2004/usslav/ ] Image courtesy United States Geological Survey [ http://www.usgs.gov/ ] |
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Earthquake Spawns Tsunamis
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Earthquake Spawns Tsunamis |
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The true-color image above shows an inlet of Little Andaman Island, near the village of Kwate-tu-Kwage. Little Andaman Island is part of India?s Andaman Island chain, situated in the eastern Indian Ocean roughly 965 km (600 miles) south-southeast of Bangladesh. The image shows a swath of destruction (grayish patches) just inland from the beach as buildings and houses were damaged or swept away by surging seawater. The image was acquired on January 2, 2005, by the IKONOS satellite. On December 26, 2004, a magnitude 9.0 earthquake hit off the west coast of Sumatra, [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12640 ] Indonesia, sending shockwaves and tsunamis radiating out from the epicenter. [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12645 ] According to news reports, as of January 2, 2005, no relief aid has been sent to the Andaman and Nicobar Islands and little is currently known about the extent of the damage and loss of life there. Although this scene is partly obscured by a thin cloud overhead, many striking details can be seen in the full-resolution copy. A dark crescent of standing water can be seen to the west (left) of the village?possibly the remnants of the tsunami. The image also reveals tsunami destruction to structures along the coast and damage fairly far inland as well. In some cases structures have been ripped off foundations, which is especially noticeable near the inlet. Image copyright Space Imaging [ http://www.spaceimaging.com/ ] |
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Earthquake Spawns Tsunamis
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Earthquake Spawns Tsunamis |
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These maps show modeled maximum wave height (top) and travel time (lower) for the Indian Ocean Tsunami of December 26, 2004. Although the epicenter of the earthquake that triggered the tsunami was near the northern tip of Sumatra, the sea floor shifted along an arc stretching about 1200 km to the north. This shifting pushes a mass of water across the Indian Ocean. The top map shows the maximum wave height that likely occured when the wave came ashore. The coastline of Sumatra, near the fault boundary, received waves over 10 meters tall, while those farther away (Sri Lanka and Thailand) were caught by waves over 4 meters. On the other side of the Indian Ocean, Somalia and the Seychelles were struck by waves approaching 4 meters in height. Travel times (lower) ranged from minutes (Sumatra) to 8 hours (Somalia) or more. Maps courtesy NOAA Pacific Marine Environmental Laboratory Tsunami Research Program [ http://www.pmel.noaa.gov/tsunami/ ] |
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Earthquake Spawns Tsunamis
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Earthquake Spawns Tsunamis |
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The island of Sumatra suffered from both the rumblings of the submarine earthquake and the tsunamis that were generated on December 26, 2004. Within minutes of the quake, the sea surged ashore, bringing destruction to the coasts of the northern Sumatra. This pair of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA?s Terra satellite shows the Aceh province of northern Sumatra, Indonesia, on December 17, 2004, before the quake (bottom), and on December 29, 2004 (top), three days after the catastrophe. Though MODIS was not specifically designed to make the very detailed observations that are usually necessary for mapping coastline changes, the sensor nevertheless observed obvious differences in the Sumatran coastline. On December 17, the green vegetation along the west coast appears to reach all the way to the sea, with only an occasional thin stretch of white that is likely sand. After the earthquake and tsunamis, the entire western coast is lined with a noticeable purplish-brown border. The brownish border could be deposited sand, or perhaps exposed soil that was stripped bare of vegetation when the large waves rushed ashore and then raced away. On a moderate-resolution image such as this, the affected area may seem small, but each pixel in the full resolution image is 250 by 250 meters. In places the brown strip reaches inland roughly 13 pixels, equal to a distance of 3.25 kilometers, or about 2 miles. On the northern tip of the island (shown in the large image), the incursion is even larger. NASA images created by Jesse Allen, Earth Observatory, using data obtained from the MODIS Rapid Response team and the Goddard Earth Sciences DAAC. |
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Earthquake Spawns Tsunamis
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Earthquake Spawns Tsunamis |
| Description |
The island of Sumatra suffered from both the rumblings of the submarine earthquake and the tsunamis that were generated on December 26, 2004. Within minutes of the quake, the sea surged ashore, bringing destruction to the coasts of the northern Sumatra. This pair of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA?s Terra satellite shows the Aceh province of northern Sumatra, Indonesia, on December 17, 2004, before the quake (bottom), and on December 29, 2004 (top), three days after the catastrophe. Though MODIS was not specifically designed to make the very detailed observations that are usually necessary for mapping coastline changes, the sensor nevertheless observed obvious differences in the Sumatran coastline. On December 17, the green vegetation along the west coast appears to reach all the way to the sea, with only an occasional thin stretch of white that is likely sand. After the earthquake and tsunamis, the entire western coast is lined with a noticeable purplish-brown border. The brownish border could be deposited sand, or perhaps exposed soil that was stripped bare of vegetation when the large waves rushed ashore and then raced away. On a moderate-resolution image such as this, the affected area may seem small, but each pixel in the full resolution image is 250 by 250 meters. In places the brown strip reaches inland roughly 13 pixels, equal to a distance of 3.25 kilometers, or about 2 miles. On the northern tip of the island (shown in the large image), the incursion is even larger. NASA images created by Jesse Allen, Earth Observatory, using data obtained from the MODIS Rapid Response team and the Goddard Earth Sciences DAAC. |
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Earthquake Spawns Tsunamis
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Earthquake Spawns Tsunamis |
| Description |
Among the first places to be affected by the massive tidal wave that ripped across the Indian Ocean on December 26, 2004, were the Andaman Islands. Located approximately 850 kilometers north of the epicenter of the earthquake that triggered the tsunami, the islands were not only among the first land masses to be swept under the wave, they have also been rattled by a series of aftershocks. Administrated by the Indian government, about 300,000 people live on the remote island chain, including several indigenous tribes. As of January 3, over 6,000 were confirmed dead or missing in the Andaman Islands. This Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) image pair shows a portion of the Andaman Islands on January 3, 2005, left, and January 23, 2003, right. In the most recent image, the beaches along the west side of the islands have been stripped bare, leaving a strip of bright tan land along the coast. The change is most notable on North Sentinel Island, home of the Sentinelese aboriginals, and on Interview Island, where the formerly green coastline has been replaced with an abnormally bright ring of bare sand. North Sentinel is fringed by a coral reef, which appears turquiose in the pre-tsunami image, but which may have been smothered in sand and sediment in the post-tsunami image. The large image reveals additional damage along all the islands of the Andaman chain. NASA images courtesy Jacques Descloitres, MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC. Both the 2005 and 2003 images are available in additional resolutions. |
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Earthquake Spawns Tsunamis
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Earthquake Spawns Tsunamis |
| Description |
Among the first places to be affected by the massive tidal wave that ripped across the Indian Ocean on December 26, 2004, were the Andaman Islands. Located approximately 850 kilometers north of the epicenter of the earthquake that triggered the tsunami, the islands were not only among the first land masses to be swept under the wave, they have also been rattled by a series of aftershocks. Administrated by the Indian government, about 300,000 people live on the remote island chain, including several indigenous tribes. As of January 3, over 6,000 were confirmed dead or missing in the Andaman Islands. This Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) image pair shows a portion of the Andaman Islands on January 3, 2005, left, and January 23, 2003, right. In the most recent image, the beaches along the west side of the islands have been stripped bare, leaving a strip of bright tan land along the coast. The change is most notable on North Sentinel Island, home of the Sentinelese aboriginals, and on Interview Island, where the formerly green coastline has been replaced with an abnormally bright ring of bare sand. North Sentinel is fringed by a coral reef, which appears turquiose in the pre-tsunami image, but which may have been smothered in sand and sediment in the post-tsunami image. The large image reveals additional damage along all the islands of the Andaman chain. NASA images courtesy Jacques Descloitres, MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC. Both the 2005 and 2003 images are available in additional resolutions. |
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Earthquake Spawns Tsunamis
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Earthquake Spawns Tsunamis |
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Satellites continue to acquire imagery of areas severely damaged by the tsunami of December 26, 2004. This image of Meulaboh, Indonesia, was collected on January 7, 2005, by DigitalGlobe?s [ http://www.digitalglobe.com/ ] QuickBird satellite. Meulaboh is located on the coast of Sumatra, roughly 150 kilometers (93 miles) from the epicenter of the magnitude 9.0 earthqukae that generated the tsunami. The image shows where the tsunami washed over a narrow peninsula, eroding the beach and destroying many of the town?s buildings. Image copyright DigitalGlobe [ http://www.digitalglobe.com/ ] |
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Earthquake Spawns Tsunamis
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Earthquake Spawns Tsunamis |
| Description |
Satellites continue to acquire imagery of areas severely damaged by the tsunami of December 26, 2004. This image of Meulaboh, Indonesia, was collected on January 7, 2005, by DigitalGlobe?s [ http://www.digitalglobe.com/ ] QuickBird satellite. Meulaboh is located on the coast of Sumatra, roughly 150 kilometers (93 miles) from the epicenter of the magnitude 9.0 earthqukae that generated the tsunami. The image shows where the tsunami washed over a narrow peninsula, eroding the beach and destroying many of the town?s buildings. Image copyright DigitalGlobe [ http://www.digitalglobe.com/ ] |
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Earthquake Spawns Tsunamis
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Earthquake Spawns Tsunamis |
| Description |
Satellites continue to acquire imagery of areas severely damaged by the tsunami of December 26, 2004. This image of Meulaboh, Indonesia, was collected on January 7, 2005, by DigitalGlobe?s [ http://www.digitalglobe.com/ ] QuickBird satellite. Meulaboh is located on the coast of Sumatra, roughly 150 kilometers (93 miles) from the epicenter of the magnitude 9.0 earthqukae that generated the tsunami. The image shows where the tsunami washed over a narrow peninsula, eroding the beach and destroying many of the town?s buildings. Image copyright DigitalGlobe [ http://www.digitalglobe.com/ ] |
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Earthquake Spawns Tsunamis
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Earthquake Spawns Tsunamis |
| Description |
*Earthquake Spawns Tsunamis*, Nearly three weeks after an earthquake triggered the deadly Indian Ocean tsunami on December 26, 2004, satellite analysis continues to illustrate the magnitude of the disaster. This pair of ASTER images contrasts before and after views of a portion of the western coastline of Thailand in the Phang-Nga province, about 50 kilometers north of the island of Phuket. In these images, vegetation is dark red, while bare earth is grey. On December 31, five days after the waves swept ashore, large sections of the shoreline are grey, stripped of vegetation or covered in mud and sand. Water has broken through several places along the northern beach. Tiny fingers of blue water slice into the land where no inlet existed in the image on the right. Like Phuket, this region of coastline is a tourist mecca, and beachfront on the Andaman Sea (left edge of both images) is dotted with golf courses, resorts, and other tourist-centered development, as well as national marine and terrestrial parks, including the Khao Lak-lam Ru National Park. Most of the land in the park is found in the mountainous region away from the shore, just to the south of the center of the images. However, the park?s terrain also includes the forest-covered cape that extends westward into the Andaman Sea. The image acquired before the tsunami is actually a composite of two separate ASTER images. The left third of the image was acquired on November 15, 2002, while the right two-thirds of the image was taken on February 28, 2003. Neither scene covered the same area as the December 31 image, but by combining the two, a comparison image can be made. The comparison shows an interesting pattern of damage along the coast. It is the long, smoothly curving beaches that have been devastated by the tsunami, not the land that juts into the ocean. Several factors probably contributed to this pattern. First, elevation is certainly a factor. The headland in the center of the image is probably a high rocky point that would not be easily inundated by a large wave. The wrinkle of inland mountains appears to curve out to the coast between the two damaged beaches. The beaches, on the other hand, probably have a low elevation that gently slopes toward the ocean, allowing any water that comes ashore to sweep further inland. Second, the headland itself may have contributed to the damage on its flanks. Waves approaching the point would tend to be diffracted, or broken up, sending additional energy into the beaches on either side of the point. This would amplify the waves along the beaches. By the same principle, the concave shape of the beach to the south focuses wave energy and wave run-up. Another contributing factor to the pattern of damage seen here is ocean bathymetry, the shape and depth of the ocean floor. Tsunami height and run-out (the horizontal distance the wave travels) are larger where the ocean floor has a gentle slope. Rocky coastlines that drop into deep ocean are not as affected. Finally,, vegetation patterns may have altered the type of damage the wave created when it came ashore. The forested cape appears to be untouched, possibly because the trees served as a break. The developed beach land probably had less dense vegetation to cushion the wave?s impact. NASA images created by Jesse Allen, Earth Observatory, using data provided courtesy NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Image interpretation courtesy Tim Gubbels, SSAI. |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
*Earthquake Spawns Tsunamis*, Nearly three weeks after an earthquake triggered the deadly Indian Ocean tsunami on December 26, 2004, satellite analysis continues to illustrate the magnitude of the disaster. This pair of ASTER images contrasts before and after views of a portion of the western coastline of Thailand in the Phang-Nga province, about 50 kilometers north of the island of Phuket. In these images, vegetation is dark red, while bare earth is grey. On December 31, five days after the waves swept ashore, large sections of the shoreline are grey, stripped of vegetation or covered in mud and sand. Water has broken through several places along the northern beach. Tiny fingers of blue water slice into the land where no inlet existed in the image on the right. Like Phuket, this region of coastline is a tourist mecca, and beachfront on the Andaman Sea (left edge of both images) is dotted with golf courses, resorts, and other tourist-centered development, as well as national marine and terrestrial parks, including the Khao Lak-lam Ru National Park. Most of the land in the park is found in the mountainous region away from the shore, just to the south of the center of the images. However, the park?s terrain also includes the forest-covered cape that extends westward into the Andaman Sea. The image acquired before the tsunami is actually a composite of two separate ASTER images. The left third of the image was acquired on November 15, 2002, while the right two-thirds of the image was taken on February 28, 2003. Neither scene covered the same area as the December 31 image, but by combining the two, a comparison image can be made. The comparison shows an interesting pattern of damage along the coast. It is the long, smoothly curving beaches that have been devastated by the tsunami, not the land that juts into the ocean. Several factors probably contributed to this pattern. First, elevation is certainly a factor. The headland in the center of the image is probably a high rocky point that would not be easily inundated by a large wave. The wrinkle of inland mountains appears to curve out to the coast between the two damaged beaches. The beaches, on the other hand, probably have a low elevation that gently slopes toward the ocean, allowing any water that comes ashore to sweep further inland. Second, the headland itself may have contributed to the damage on its flanks. Waves approaching the point would tend to be diffracted, or broken up, sending additional energy into the beaches on either side of the point. This would amplify the waves along the beaches. By the same principle, the concave shape of the beach to the south focuses wave energy and wave run-up. Another contributing factor to the pattern of damage seen here is ocean bathymetry, the shape and depth of the ocean floor. Tsunami height and run-out (the horizontal distance the wave travels) are larger where the ocean floor has a gentle slope. Rocky coastlines that drop into deep ocean are not as affected. Finally,, vegetation patterns may have altered the type of damage the wave created when it came ashore. The forested cape appears to be untouched, possibly because the trees served as a break. The developed beach land probably had less dense vegetation to cushion the wave?s impact. NASA images created by Jesse Allen, Earth Observatory, using data provided courtesy NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Image interpretation courtesy Tim Gubbels, SSAI. |
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Earthquake Spawns Tsunamis
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Earthquake Spawns Tsunamis |
| Description |
On December 26, 2004, a large (magnitude 9.0) earthquake occurred off the western coast of Sumatra in the Indian Ocean. The earthquake was caused by the release of stresses accumulated as the Burma tectonic plate overrides the India tectonic plate. Movement of the seafloor due to the earthquake generated a tsunami, or seismic sea wave, that affected coastal regions around the Indian Ocean. The northwestern Sumatra coastline in particular suffered extensive damage and loss of life. These astronaut photographs illustrate damage along the southwestern coast of Aceh Province in the vicinity of the city of Lho? Kruet, Indonesia. Large areas of bare and disturbed soil (brownish gray) that were previously covered with vegetation are visible along the coastline in the near-nadir (top) image. Embayments in the coastline were particularly hard hit, while adjacent headlands were less affected. The oblique (lower) astronaut photograph was acquired 45 seconds after the near-nadir photograph, and captures sunglint illuminating the Indian Ocean and standing water inland (light gray, yellow). Distortion and scale differences in the images are caused by increased obliquity of the view from the International Space Station. Arrows on the photographs indicate several points of comparison between the two images. Standing bodies of seawater may inhibit revegetation of damaged areas and act as sources of salt contamination in soil and groundwater. Astronaut photographs ISS010-E-13079 [ http://eol.jsc.nasa.gov/scripts/sseop/photo.pl?mission=ISS010&roll=E&frame=13079 ] (top) and ISS010-E-13088 [ http://eol.jsc.nasa.gov/scripts/sseop/photo.pl?mission=ISS010&roll=E&frame=13088 ] (bottom) were acquired January 15, 2005 with a Kodak 760C digital camera using a 400 mm lens, and are provided by the ISS Crew Earth Observations experiment and the Image Science & Analysis Group, Johnson Space Center. The International Space Station Program [ http://spaceflight.nasa.gov/home/index.html ] supports the laboratory to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. [ http://eol.jsc.nasa.gov/ ] |
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Earthquake Spawns Tsunamis
| Title |
Earthquake Spawns Tsunamis |
| Description |
On December 26, 2004, a large (magnitude 9.0) earthquake occurred off the western coast of Sumatra in the Indian Ocean. The earthquake was caused by the release of stresses accumulated as the Burma tectonic plate overrides the India tectonic plate. Movement of the seafloor due to the earthquake generated a tsunami, or seismic sea wave, that affected coastal regions around the Indian Ocean. The northwestern Sumatra coastline in particular suffered extensive damage and loss of life. These astronaut photographs illustrate damage along the southwestern coast of Aceh Province in the vicinity of the city of Lho? Kruet, Indonesia. Large areas of bare and disturbed soil (brownish gray) that were previously covered with vegetation are visible along the coastline in the near-nadir (top) image. Embayments in the coastline were particularly hard hit, while adjacent headlands were less affected. The oblique (lower) astronaut photograph was acquired 45 seconds after the near-nadir photograph, and captures sunglint illuminating the Indian Ocean and standing water inland (light gray, yellow). Distortion and scale differences in the images are caused by increased obliquity of the view from the International Space Station. Arrows on the photographs indicate several points of comparison between the two images. Standing bodies of seawater may inhibit revegetation of damaged areas and act as sources of salt contamination in soil and groundwater. Astronaut photographs ISS010-E-13079 [ http://eol.jsc.nasa.gov/scripts/sseop/photo.pl?mission=ISS010&roll=E&frame=13079 ] (top) and ISS010-E-13088 [ http://eol.jsc.nasa.gov/scripts/sseop/photo.pl?mission=ISS010&roll=E&frame=13088 ] (bottom) were acquired January 15, 2005 with a Kodak 760C digital camera using a 400 mm lens, and are provided by the ISS Crew Earth Observations experiment and the Image Science & Analysis Group, Johnson Space Center. The International Space Station Program [ http://spaceflight.nasa.gov/home/index.html ] supports the laboratory to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. [ http://eol.jsc.nasa.gov/ ] |
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Eruption on Barren Island
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Eruption on Barren Island |
| Description |
The volcano on Barren Island erupted on August 24, 2005. A part of India, Barren Island is one of the Andaman Islands, and lies over the fault whose movement caused the tsunami on December 26, 2004. It is a stratovolcano composed of lava, rock fragments, and volcanic ash. On the west side of the island is a caldera formed by an explosive eruption in the Pleistocene era. Two kilometers wide, the caldera takes up the bulk of this tiny island that measures only 3 kilometers across. The Moderate Resolution Imaging Spectroradiometer (MODIS) [ http://modis.gsfc.nasa.gov/ ] flying onboard the Aqua [ http://aqua.nasa.gov/ ] satellite captured this image on August 24, 2005. In this image, smoke blows from the volcano eastward over the Andaman Sea toward a bank of clouds. The red outline indicates surface area hotter than its surroundings. NASA image created by Jeff Schmaltz, MODIS Rapid Response team. |
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North Reef Island, Andaman S
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North Reef Island, Andaman Sea |
| Description |
On December 26, 2004, one of the largest earthquakes in recorded history struck offshore of the island of Sumatra, Indonesia. The ocean floor heaved in some places and sank in others, creating catastrophic tsunamis that raced across the Indian Ocean. Hundreds of thousands of people died as the waves struck coastlines from Thailand to Sri Lanka to Somalia. In addition to tsunami damage, satellite images of reefs, islands, and coastlines identified signs of permanent elevation change—sinking or uplift—along the fault between the Indo-Australia and Burma plates. [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12640 ] In places such as North Reef Island, shown in this pair of images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov ] on NASA's Terra [ http://terra.nasa.gov ] satellite, the quake lifted the reefs permanently out of the water. The images use visible and infrared light detected by ASTER to make different land surfaces stand out clearly from one another: water is blue, vegetation is red, coral or bare sand appears white. In the "before" image, from December 2, 2004, the submerged reef creates a bright blue glow around the island. In the "after" image, from February 4, 2005, the white coral stands completely up out of the water. It is even tinged with red, which suggests the exposed coral had died, and algae had colonized it. In the weeks and months after the earthquake, satellite images provided broad coverage of an area where ground-based observations were initially very limited. A team of scientists led by Caltech Ph.D. geology student Aron Meltzner discovered changes in elevation along nearly 1,600 kilometers (994 miles) of the tectonic plate boundary. The images revealed that the earthquake rupture extended 100 kilometers (62 miles) farther north than estimates based on seismic and Global Positioning System (GPS) data suggested. The feature article Rise and Fall: Satellites Reveal Full Length of Tsunami-Generating Earthquake [ http://earthobservatory.nasa.gov/Study/Aceh/aceh.html ] describes how scientists used satellite images to map the length of the earthquake rupture zone. The article includes additional satellite and ground-based images of elevation changes resulting from the 2004 Aceh-Andaman earthquake. NASA images created by Jesse Allen, Earth Observatory, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. [ http://asterweb.jpl.nasa.gov/ ] |
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North Reef Island, Andaman S
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| Title |
North Reef Island, Andaman Sea |
| Description |
On December 26, 2004, one of the largest earthquakes in recorded history struck offshore of the island of Sumatra, Indonesia. The ocean floor heaved in some places and sank in others, creating catastrophic tsunamis that raced across the Indian Ocean. Hundreds of thousands of people died as the waves struck coastlines from Thailand to Sri Lanka to Somalia. In addition to tsunami damage, satellite images of reefs, islands, and coastlines identified signs of permanent elevation change—sinking or uplift—along the fault between the Indo-Australia and Burma plates. [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12640 ] In places such as North Reef Island, shown in this pair of images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov ] on NASA's Terra [ http://terra.nasa.gov ] satellite, the quake lifted the reefs permanently out of the water. The images use visible and infrared light detected by ASTER to make different land surfaces stand out clearly from one another: water is blue, vegetation is red, coral or bare sand appears white. In the "before" image, from December 2, 2004, the submerged reef creates a bright blue glow around the island. In the "after" image, from February 4, 2005, the white coral stands completely up out of the water. It is even tinged with red, which suggests the exposed coral had died, and algae had colonized it. In the weeks and months after the earthquake, satellite images provided broad coverage of an area where ground-based observations were initially very limited. A team of scientists led by Caltech Ph.D. geology student Aron Meltzner discovered changes in elevation along nearly 1,600 kilometers (994 miles) of the tectonic plate boundary. The images revealed that the earthquake rupture extended 100 kilometers (62 miles) farther north than estimates based on seismic and Global Positioning System (GPS) data suggested. The feature article Rise and Fall: Satellites Reveal Full Length of Tsunami-Generating Earthquake [ http://earthobservatory.nasa.gov/Study/Aceh/aceh.html ] describes how scientists used satellite images to map the length of the earthquake rupture zone. The article includes additional satellite and ground-based images of elevation changes resulting from the 2004 Aceh-Andaman earthquake. NASA images created by Jesse Allen, Earth Observatory, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. [ http://asterweb.jpl.nasa.gov/ ] |
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Fires in Southeast Asia
| Title |
Fires in Southeast Asia |
| Description |
Seasonal agricultural burning continued to intensify across Southeast Asia on December 26, 2004. In this image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA?s Terra satellite, the locations of actively burning fires across Thailand, Cambodia, and Laos are marked with red dots. Two particularly concentrated areas of burning are visible. One is in the northern part of the broad river valley in western Thailand, at image left. The other is to the west of the Tônlé Sap (a large lake that quintuples in size during the wet phase of the monsoon) in Cambodia. The widespread nature of the fires, their location (generally located away from remaining natural vegetation, which appears deeper green), and the time of year suggest that these fires are being set intentionally for agricultural purposes. Though not necessarily immediately hazardous, such large-scale burning can have a strong impact on weather, climate, human health, and natural resources. NASA image courtesy the MODIS Rapid Response Team, NASA-Goddard Space Flight Center |
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Tsunami Inundation, North of
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PIA06671
Sol (our sun)
ASTER, SIR-C/X-SAR
| Title |
Tsunami Inundation, North of Phuket, Thailand ASTER Images and SRTM Elevation Model |
| Original Caption Released with Image |
Figure 1 The Indian Ocean coastline north of Phuket, Thailand is a major tourist destination that was in the path of the tsunami produced by a giant offshore earthquake on December 26, 2004. This disaster resulted in a heavy loss of life. These simulated natural color ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) images show a 27 kilometer (17-mile) long stretch of coast 80 kilometers (50 miles) north of the Phuket airport in the Khao Lak area on December 31 (middle) and also two years earlier (left). The changes along the coast are obvious (changing from green to grey) where the vegetation was stripped away by the tsunami. The image on the right is a copy of the later ASTER scene but it includes highlighting in red for areas that have elevations within 10 meters (33 feet) of sea level. This elevation information was supplied by the Shuttle Radar Topography Mission (SRTM). The red areas appear to include most of the tsunami inundated areas. The geographic correspondence of the imaged damage and the highlighted elevation range is quite good in the middle and upper parts of the scene and is consistent with an early field report of about 10 meters of inundation. In the south, the elevation range corresponds to a much wider area than the actual damage, but this is to be expected for areas increasingly far from the coast. Offshore bathymetry (depth variations), coastal landforms, distance from the coast, and additional factors other than elevation range control the damage extent. But elevation measurements along the coast, as provided by SRTM, give a general indication of areas at risk, as now confirmed by ASTER. ASTER images Earth to map and monitor the changing surface of our planet with its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet). These data provide scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate. 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. 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 Science Mission Directorate, Washington, D.C. Size: 9.75 x 27.6 kilometers (6.0 x 17.1 miles), Location: 8.6 degrees North latitude, 98.3 degrees East longitude Orientation: Top is 8.25 degrees east of North Image Data: ASTER Bands 1, 2, 3 mixed for simulated true color. Date Acquired: November 15, 2002 and December 31, 2004 (ASTER), February 2000 (SRTM) |
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Tsunami Inundation, North of
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PIA06671
Sol (our sun)
ASTER, SIR-C/X-SAR
| Title |
Tsunami Inundation, North of Phuket, Thailand ASTER Images and SRTM Elevation Model |
| Original Caption Released with Image |
Figure 1 The Indian Ocean coastline north of Phuket, Thailand is a major tourist destination that was in the path of the tsunami produced by a giant offshore earthquake on December 26, 2004. This disaster resulted in a heavy loss of life. These simulated natural color ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) images show a 27 kilometer (17-mile) long stretch of coast 80 kilometers (50 miles) north of the Phuket airport in the Khao Lak area on December 31 (middle) and also two years earlier (left). The changes along the coast are obvious (changing from green to grey) where the vegetation was stripped away by the tsunami. The image on the right is a copy of the later ASTER scene but it includes highlighting in red for areas that have elevations within 10 meters (33 feet) of sea level. This elevation information was supplied by the Shuttle Radar Topography Mission (SRTM). The red areas appear to include most of the tsunami inundated areas. The geographic correspondence of the imaged damage and the highlighted elevation range is quite good in the middle and upper parts of the scene and is consistent with an early field report of about 10 meters of inundation. In the south, the elevation range corresponds to a much wider area than the actual damage, but this is to be expected for areas increasingly far from the coast. Offshore bathymetry (depth variations), coastal landforms, distance from the coast, and additional factors other than elevation range control the damage extent. But elevation measurements along the coast, as provided by SRTM, give a general indication of areas at risk, as now confirmed by ASTER. ASTER images Earth to map and monitor the changing surface of our planet with its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet). These data provide scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate. 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. 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 Science Mission Directorate, Washington, D.C. Size: 9.75 x 27.6 kilometers (6.0 x 17.1 miles), Location: 8.6 degrees North latitude, 98.3 degrees East longitude Orientation: Top is 8.25 degrees east of North Image Data: ASTER Bands 1, 2, 3 mixed for simulated true color. Date Acquired: November 15, 2002 and December 31, 2004 (ASTER), February 2000 (SRTM) |
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Uplift and Subsidence Associ
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PIA02435
Sol (our sun)
ASTER
| Title |
Uplift and Subsidence Associated with the Great Aceh-Andaman Earthquake of 2004 |
| Original Caption Released with Image |
The magnitude 9.2 Indian Ocean earthquake of December 26, 2004, produced broad regions of uplift and subsidence. In order to define the lateral extent and the downdip limit of rupture, scientists from Caltech, Pasadena, Calif., NASA's Jet Propulsion Laboratory, Pasadena, Calif., Scripps Institution of Oceanography, La Jolla, Calif., the U.S. Geological Survey, Pasadena, Calif., and the Research Center for Geotechnology, Indonesian Institute of Sciences, Bandung, Indonesia, first needed to define the pivot line separating those regions. Interpretation of satellite imagery and a tidal model were one of the key tools used to do this. These pre-Sumatra earthquake (a) and post-Sumatra earthquake (b) images of North Sentinel Island in the Indian Ocean, acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft, show emergence of the coral reef surrounding the island following the earthquake. The tide was 30 plus or minus 14 centimeters lower in the pre-earthquake image (acquired November 21, 2000) than in the post-earthquake image (acquired February 20, 2005), requiring a minimum of 30 centimeters of uplift at this locality. Observations from an Indian Coast Guard helicopter on the northwest coast of the island suggest that the actual uplift is on the order of 1 to 2 meters at this site. In figures (c) and (d), pre-earthquake and post-earthquake ASTER images of a small island off the northwest coast of Rutland Island, 38 kilometers east of North Sentinel Island, show submergence of the coral reef surrounding the island. The tide was higher in the pre-earthquake image (acquired January 1, 2004) than in the post-earthquake image (acquired February 4, 2005), requiring subsidence at this locality. The pivot line must run between North Sentinel and Rutland islands. Note that the scale for the North Sentinel Island images differs from that for the Rutland Island images. The tidal model used for this study was based on data from JPL's Topex/Poseidon satellite. The model was used to determine the relative sea surface height at each location at the time each image was acquired, a critical component used to quantify the deformation. The scientists' method of using satellite imagery to recognize changes in elevation relative to sea surface height and of using a tidal model to place quantitative bounds on coseismic uplift or subsidence is a novel approach that can be adapted to other forms of remote sensing and can be applied to other subduction zones in tropical regions. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with, critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate. |
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Sri Lanka, Colored Height
PIA06670
Sol (our sun)
C-Band Interferometric Radar
| Title |
Sri Lanka, Colored Height |
| Original Caption Released with Image |
The topography of the island nation of Sri Lanka is well shown in this color-coded shaded relief map generated with digital elevation data from the Shuttle Radar Topography Mission (SRTM). Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations. For this special view heights below 10 meters (33 feet) above sea level have been colored red. These low coastal elevations extend 5 to 10 km (3.1 to 6.2 mi) inland on Sri Lanka and are especially vulnerable to flooding associated with storm surges, rising sea level, or, as in the aftermath of the earthquake of December 26, 2004, tsunami. These so-called tidal waves have occurred numerous times in history and can be especially destructive, but with the advent of the near-global SRTM elevation data planners can better predict which areas are in the most danger and help develop mitigation plans in the event of particular flood events. Sri Lanka is shaped like a giant teardrop falling from the southern tip of the vast Indian subcontinent. It is separated from India by the 50km (31mi) wide Palk Strait, although there is a series of stepping-stone coral islets known as Adam's Bridge that almost form a land bridge between the two countries. The island is just 350km (217mi) long and only 180km (112mi) wide at its broadest, and is about the same size as Ireland, West Virginia or Tasmania. The southern half of the island is dominated by beautiful and rugged hill country, and includes Mt Pidurutalagala, the islandâ??s highest point at 2524 meters (8281 ft). The entire northern half comprises a large plain extending from the edge of the hill country to the Jaffna peninsula. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 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 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Geospatial-Intelligence Agency (NGA) of the U.S. Department of Defense 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, D.C. Location: 8.0 degrees North latitude, 80.7 degrees East longitude Orientation: North, toward the top, Mercator projection Size: 275.6 by 482.4 kilometers (165.4 by 299.0 miles) Image Data: shaded and colored SRTM elevation model Date Acquired: February 2000 |
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New NASA Imagery Sheds Addit
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PIA07227
Sol (our sun)
ASTER
| Title |
New NASA Imagery Sheds Additional Perspectives on Tsunami |
| Original Caption Released with Image |
The island of Phuket on the Indian Ocean coast of Thailand is a major tourist destination and was also in the path of the tsunami that washed ashore on December 26, 2004, resulting in a heavy loss of life. These simulated natural color ASTER images show a 27 kilometer (17-mile) long stretch of coast north of the Phuket airport on December 31 (right), along with an image acquired two years earlier (left). The changes along the coast are obvious where the vegetation has been stripped away. These images are being used to create damage assessment maps for the U.S. Agency for International Development (USAID) Office of Foreign Disaster Assistance. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate. Size: 9.8 by 27.6 kilometers (6.1 by 17.1 miles) Location: 8.6 degrees North latitude, 98.2 degrees East longitude Orientation: North at top Image Data: ASTER bands 3,2, and 1 Original Data Resolution: 15 meters (49.2 feet) Dates Acquired: November 15, 2002, and December 31, 2004 |
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NASA/French Satellite Data R
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PIA07219
Sol (our sun)
Altimeter
| Title |
NASA/French Satellite Data Reveal New Details of Tsunami |
| Original Caption Released with Image |
Displayed in blue color is the height of sea surface (shown in blue) measured by the Jason satellite two hours after the initial magnitude 9 earthquake hit the region (shown in red) southwest of Sumatra on December 26, 2004. The data were taken by a radar altimeter onboard the satellite along a track traversing the Indian Ocean when the tsunami waves had just filled the entire Bay of Bengal (see the model simulation inset image). The data shown are the changes of sea surface height from previous observations made along the same track 20-30 days before the earthquake, reflecting the signals of the tsunami waves. The maximum height of the leading wave crest was about 50 cm (or 1.6 ft), followed by a trough of sea surface depression of 40 cm. The directions of wave propagation along the satellite track are shown by the blue arrows. "Model Simulation:" Simulated changes of sea surface height caused by the earthquake two hours after the initial shock. The simulation was performed using a computer model and provided for public access via internet by Kenji Satake, National Institute of Advanced Industrial Science and Technology, Japan (http://www.ioc.unesco.org/itsu/templates/itsu/images/animation.gif). Wave crests are shown in red and troughs in blue. The track traversed by the Jason satellite was also shown. The simulated crests and troughs along the track are in agreement with the satellite observations. The map provides a basin-wide perspective for interpreting the satellite observations along a single track. |
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| General Description |
International Space Station Imagery |
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| General Description |
International Space Station Imagery |
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