Prof. Philip Liu, civil and environmental engineering, delayed his return to Ithaca last week following an invitation from Thailand’s Knowledge Network Institute, a think-tank organization that aims “to promote knowledge management in Thai society.” He had been the leader of the recent scientific expedition to Sri Lanka to survey the tsunami’s impact.
“They invited me to talk about Sri Lanka,” Liu said. Their central purpose for inviting him, however, was to “help the higher commission of education organize … a tsunami warning system,” he added.
At present, tsunamis are extremely unpredictable. Their evolution can be accurately modeled once the tsunami has been generated, but only if very specific details about the wave’s triggering mechanism, such as an earthquake or landslide, are known. In the case of an earthquake, “you really need to know the fault characteristics,” Liu explained. “If the earthquake does not have any kind of vertical displacement, then no tsunami will be generated.”
In most cases, tsunami-triggering earthquakes or landslides are, at best, difficult to forecast, so the goal of a tsunami warning system is to detect existing tsunamis as early as possible. In the Pacific Ocean, the presence of deep-sea buoys installed by the National Oceanic and Atmospheric Association has provided scientists with “an immediate warning in the event of a tsunami,” Liu explained. However, in the Indian Ocean, these underwater sensors have remained absent.
“There is at least an hour and a half for the wave to travel from the [earthquake’s] epicenter to the coastline,” Liu said. Thus, if deep-ocean buoys were strategically placed in the Indian Ocean, governments would have approximately “30 minutes lead time to send out the warning message,” Liu said.
The exact number of sensors and their locations has not yet been investigated, but their positions would be determined largely by the configurations of active seismic zones, according to Liu.
“We need to work with the seismologists and look at some statistics,” he said. Another important aspect of the warning system involves “educating people so that [they] will know how to react in the case of a tsunami,” Liu said. The population has to know how to respond and the government has to have an evacuation plan available. “Only then does the warning system become effective,” Lui added.
Liu’s research has focused primarily on the interactions between ocean waves, coastlines and coastal structures. He has studied these interactions in wind waves, ocean waves of small wavelengths and several tsunamis–ocean waves of extremely large wavelength–prior to the recent Sri Lanka tsunami. As with previous damaging tsunamis, much of the structural damage to buildings appeared to be the result of low building standards. In Sri Lanka, most of “the damaged buildings had no reinforcement at all,” Liu said.
Liu has been involved in civil engineering and ocean wave research at Cornell for nearly 30 years and has studied tsunamis since the early ’80s. He was involved in developing numerical models that describe the evolution of tsunamis and has since investigated their behavior near the shoreline. Liu’s research has also attracted various domestic and international organizations and recently captured the interest of scientists through his expedition to tsunami-ravaged Sri Lanka.
“Professor Liu was the organizer of the expedition … a major reason I was attracted to it,” said Bruce Jaffe, oceanographer at the U.S. Geological Survey, in describing his motivation for heading to Sri Lanka. “I plan to continue working with him,” said Prof. Harindo Fernando, a mechanical engineer at Arizona State University, in an interview after returning from the expedition. Though the tsunamis Liu has researched have occurred far away from the North American continent, the waves do have the potential to strike various areas of the United States.
“Hawaii has been affected several times, and Alaska is a very risky region,” Liu said. On the east coast, however, tsunamis have been historically rare, but “people have recently talked about the possibility of a landslide generating a tsunami, which would affect the east coast,” Liu said.
Archived article by David Andrade
Sun Staff Writer