New NASA Imagery Sheds Additional Perspectives on Tsunami
Newly released imagery from three NASA spaceborne instruments sheds
valuable insights into the Indian Ocean tsunami that resulted from
the magnitude 9 earthquake southwest of Sumatra on December 26.
Image right: The initial tsunami waves reached the eastern Indian coast around 3:35 UTC, based on tide gauge measurements made at the port city of Vishakapatnam. The Multi-angle Imaging SpectroRadiometer (MISR) aboard NASA's Terra satellite passed over the eastern Indian coast between 5:10 to 5:20 UTC, when the tide gauge indicated the arrival of another series of waves. Because MISR's nine cameras imaged the coast over a time span of about 7 minutes, and because the the waves are unusually large, MISR was able to capture unique time-lapse imagery of the breaking waves. Image credit: NASA/JPL. + More tsunami images.
The images offer several unique views of portions of the affected
region. The data are and will be used by scientists and government
agencies to assist with disaster recovery, mitigate the effects of
future natural hazards and increase our understanding of how and why
tsunamis strike. The data were acquired by the Multi-angle Imaging
SpectroRadiometer and the Advanced Spaceborne Thermal Emission and
Reflection Radiometer instruments on NASA's Terra spacecraft, as
well as from the Shuttle Radar Topography Mission.
To access the new images available on the Web, visit:
The Multi-angle Imaging SpectroRadiometer imagery includes the only
known animations produced by a remote sensing instrument to capture
tsunami waves in motion as they make landfall. The image set and
animations were collected December 26 as Terra passed over the
eastern Indian coast about an hour and a half after the first waves
hit shore. The first animation shows tsunami waves breaking along
the shores of the Indian state of Andhra Pradesh, near the mouth of
the Godavari River. Because the instrument's multiple cameras
imaged the coast over several minutes and the waves were unusually
large, the instrument captured unique time-lapse imagery of them.
The resolution is 275 meters (900 feet). The still images show
frames from four of the instrument's cameras, and span a period of
about two and a half minutes. In the second animation, waves break
further to the south, near the mouth of the Krishna River.
The data indicate the location and timing of some of the waves,
their angle relative to the shoreline and their speed, estimated
from these data to be about 30 kilometers (19 miles) per hour.
Together with measurements of ocean depth, these data can be used to
refine models of how tsunamis originate and travel. Better
understanding of how tsunamis interact with coastal areas is one
factor needed to improve near-real-time forecasts of tsunami arrival
times and effects, and to reduce damage from such waves in the
Terra's Advanced Spaceborne Thermal Emission and Reflection
Radiometer instrument acquired images of the area around Phuket on
the Indian Ocean coast of Thailand on December 31. The pair of
simulated natural color images shows a 27-kilometer (17-mile)
stretch of coast north of the Phuket airport on December 31, along
with an image acquired two years earlier. The changes along the
coast are self-evident, clearly indicating the extent of vegetation
stripped by the waves. The images are being used to create damage
assessment maps for the U.S. Agency for International Development
Office of Foreign Disaster Assistance. The resolution is 15 meters
The separate image trio depicts these same before/after views and
contrasts them with a third view created with Shuttle Radar
Topography Mission data. Elevations below 10 meters (33 feet) are
highlighted in red, and include most of the areas inundated by the
tsunami, though offshore ocean depth variations, coastal landforms,
distance from the coast and additional factors control the damage
extent. Still, elevation measurements as provided by the Shuttle
Radar Topography Mission, give a general indication of areas at
risk, and can help planners better predict which areas of a region
are in the most danger and help develop mitigation plans in the
event of particular flood events.
The Shuttle Radar Topography Mission has also produced a color-coded
shaded relief map of the island nation of Sri Lanka, highlighting
regions below 10 meters (33 feet) in elevation. The data were
collected during the 11-day Space Shuttle mission in February 2000
and released publicly in July 2003. The low coastal elevations
extend 5 to 10 kilometers (3.1 to 6.2 miles) inland and are
especially vulnerable to flooding associated with storm surges,
rising sea level and tsunami.
The Multi-angle Imaging SpectroRadiometer was built and is managed
by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Japan's
Ministry of Economy, Trade and Industry built the Advanced
Spaceborne Thermal Emission and Reflection Radiometer. NASA's
Goddard Space Flight Center, Greenbelt, Md., manages the Terra
satellite. The Shuttle Radar Topography Mission is a collaboration
of NASA, the National Geospatial-Intelligence Agency and the German
and Italian space agencies.
For more information about the three instruments/missions on the
Alan Buis (818) 354-0474
NASA's Jet Propulsion Laboratory
Gretchen Cook-Anderson (202) 358-0836 NASA Headquarters, Washington, D.C.