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.
