New Tools for Predicting Tsunamis

March 29, 2011 · 0 comments

The SWASH (Simulating Waves until at Shore) model sounds like something that would have been useful in predicting the tsunami in Japan. According to the developer Marcel Zijlema at Delft University of Technology, it quickly calculates how tall a wave is, how fast it’s moving, and how much energy it holds. Yet, Zijlema admits that unfortunately it wouldn’t have helped in this case. “The quake was 130 kilometers away, too close to the coast, and the wave was moving at 800 kilometers per hour. There was no way to help. But at a greater distance the system could literally save lives.”

SWASH is a development of the SWAN (Simulating Waves Near SHore), which has been around since 1993 and is used by over 1,000 institutions around the world. SWAN calculates wave heights and wave speeds generated by wind and can also analyze waves generated elsewhere by a distant storm.  The program can be run on an ordinary computer and the software is free.

According to Zijlema, SWASH works differently than SWAN. Because the model directly simulates the ocean surface, film clips can be generated that help in explaining the underlying physics of currents near the shore and how waves break on shore. This makes the model not only an extremely valuable in an emergency, but also makes it possible to construct effective protection against a tsunami

Like SWAN, SWASH will be available as a public domain program.

Another tool recently developed by seismologists uses multiple seismographic readings from different locations to match earthquakes to the attributes of past tsunami-causing earthquakes. For instance, the algorithm looks for undersea quakes that rupture more slowly, last longer, and are less efficient at radiating energy. These tend to cause bigger ocean waves than fast-slipping subduction quakes that dissipate energy horizontally and deep underground.

The system, known as RTerg, sends an alert within four minutes of a match to NOAA’s Pacific Tsunami Warning Center as well as the United States Geological Survey’s National Earthquake Information Center. “We developed a system that, in real time, successfully identified the magnitude 7.8 2010 Sumatran earthquake as a rare and destructive tsunami earthquake,” says Andrew Newman, assistant professor in the School of Earth and Atmospheric Sciences. “Using this system, we could in the future warn local populations, thus minimizing the death toll from tsunamis.”

Newman and his team are working on ways to improve RTerg in order to add critical minutes between the time of the earthquake and warning. They’re also planning to rewrite the algorithm to broaden its use to all U.S. and international warning centers.