Ocean, Tsunami Wave Properties To Be Topic Of March 9 CU-Boulder Talk

Published: March 2, 2005

University of Colorado at Boulder Professor Harvey Segur will give the Graduate School's 97th Distinguished Research Lecture March 9th on the topic of ocean waves, including their role in the deadly Dec. 26th Asian tsunami.

The talk is free and open to the public and will be held at 5:30 p.m. in the Club Room at Folsom Stadium across from Gate 9. The Graduate School's Council on Research and Creative Work is sponsoring the talk.

A professor in the applied mathematics department, Segur will talk on the fluid dynamics of ocean waves. He will describe research on several types of ocean waves, including common, wind-driven waves and much rarer tsunami waves, like those that killed more than 225,000 people and caused billions of dollars in destruction in 11 Indian Ocean nations on Dec. 26.

Calculating the time delay between earthquakes or underwater landslides that trigger tsunamis and the subsequent arrival times of destructive waves at distant shores is fairly straightforward, Segur said. "But it's more difficult is to predict how big and disruptive the waves will be and what types of warnings to issue," he said.

Most ocean waves are created by maritime winds and storms, he said. The height of such waves can be quite large, but their wavelengths -- the distance between successive crests, or tops -- are rarely longer than 1,000 feet. The waves generally travel at speeds of less than 50 miles per hour and often much less, he said.

In contrast, tsunami waves usually are triggered by the motion of tectonic plates or by other seismic activity under the sea, Segur said. A tsunami can be dozens of miles long, and the Asian tsunami crossed the Indian Ocean with an average speed of about 450 miles per hour.

"If the underwater plates move either up or down, as they did in triggering the 2004 Asian tsunami, the effect is to change the volume of water in the ocean," he said. "This change in volume is one of several important indicators of how destructive the tsunami will be when it reaches shore."

After the initial December tsunami wave hit, the shoreline underwent a massive "draw down" of water in places, exposing huge areas of the coastal seafloor for several minutes. "The ocean receded significantly below anything ever before seen there," said Segur. "Unfortunately, a lot of people went back out on the beach during the wave depression and were still there when the next wave came in."

Segur has been a CU-Boulder faculty member since 1989 and served as chair of the applied mathematics department from 2000 to 2003. He received a 1994 Teaching Excellence Award from the Boulder Faculty Assembly and was awarded the Minority Engineering Program's Faculty Award in 1995.

In 1998, Segur was named a President's Teaching Scholar by former CU president John Buechner. Segur has authored several books, numerous journal articles and has been a guest lecturer in 15 countries, including Germany, Russia, Japan, China and Denmark.

Segur received his master's and doctoral degrees in aeronautical sciences from the University of California, Berkeley. Before coming to CU-Boulder he was a research fellow at the California Institute of Technology, an associate professor at Clarkson College of Technology in Potsdam, N.J., and a professor at State University of New York, Buffalo.

During his professional career, Segur has conducted research in various mathematical fields for the U.S. Department of Energy, the National Science Foundation, NATO, the Office of Naval Research and the U.S. Army Research Office. He also has worked extensively in private industry during his career.

Previous CU-Boulder faculty selected to give the Graduate School's Distinguished Research Lecture include Professor Margaret Eisenhart of education (2004), Professor Allan Franklin of physics (2003), and Professors John DeFries of psychology and the Institute for Behavioral Genetics and William Wood of molecular, cellular and developmental biology (2002).

The March 9 lecture will be immediately followed by a reception. For more information on the event or the Graduate School, contact Candice Miller, director of research for the Graduate School, at (303) 735-0982 or candice.miller@colorado.edu.