January 4, 2005
UCSC geophysicist creates computer simulation
of Indian Ocean tsunami
By Tim Stephens
Soon after hearing news reports of the tsunami that devastated
coastal regions throughout the Indian Ocean, research geophysicist
Steven Ward, an expert on tsunami hazards, went to work on his
|UPDATE: Steven Ward was interviewed on campus this
week for the television news program Dateline NBC.
Although scheduling is subject to change, the program is
expected to air on Friday, January 7, at 8 p.m. on local
Using sophisticated computational techniques to simulate the
tsunami, Ward created an animated movie showing the tsunami
waves spreading out through the Indian Ocean from the site of
the powerful earthquake that triggered them.
based on the physics of earthquakes and tsunamis, is preliminary
because geologists have not yet fully characterized the earthquake,
"The tsunami model depends on earthquake parameters, so
as we learn more about the earthquake I will be able to refine
it. But the essence of the phenomenon is captured in the animation,"
A magnitude 9.0 earthquake, the most powerful earthquake recorded
in more than 40 years, struck underwater off the Indonesian
island of Sumatra on December 26. The resulting tsunami caused
devastation throughout South Asia, with the death toll now estimated
According to Ward, the speed of a tsunami depends on the depth
of the water, with waves traveling as fast as 400 miles per
hour in the deep ocean.
When they come ashore, they are typically moving at about 30
miles per hour, he said, adding that tsunami waves are very
different from the waves one usually sees at the beach.
"It's like the ocean turns into a river and starts to
flow onto the land. It's not a big crashing wave like in the
Hollywood movies," Ward said.
Tsunamis can be generated not only by earthquakes, but also
by undersea landslides and asteroid impacts. Ward has used computer
simulations to study all of these potential hazards. In 2003,
for example, he and asteroid expert Erik Asphaug, an associate
professor of Earth sciences, published a paper describing the
tsunami that could result from an asteroid that is on course
for a close encounter with Earth in the year 2880 (see Currents
In the aftermath of the disaster in South Asia, he has been
contacted by numerous media outlets, including the Washington
Post, New York Daily News, Newsweek magazine, and local
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