Letter bombs? Christmas cards? Better yet-
Southern California at risk of one-two earthquake-tsunami punch
By LEON DROUIN KEITH
Associated Press Writer
LOS ANGELES (AP) -- A tsunami generated by a Southern California earthquake could deliver 50-foot waves on the region's coastline with only a few minutes' warning, according to a study focusing on what has been a largely unstudied threat.
The University of Southern California researchers who conducted the study, to be presented at a geophysics conference Sunday, ran computer models of earthquakes off Santa Barbara and Ventura counties and found they could trigger tsunamis powerful enough to send waves a half-mile inland in some areas.
Researcher and civil and environmental engineering professor Costas Synolakis said it will take more research to figure out the likelihood of a major tsunami in Southern California.
"It's not something we can quantify easily ... it's a question that has tormented us," he said. "It's like the San Andreas Fault -- we know one day a big earthquake will hit, but we don't know when."
"Personally, I think that within our lifetime we'll see a tsunami" in Southern California, Synolakis said.
If we do, he stressed, "There's absolutely no reason to panic." Beachgoers and coastal residents simply need to move to higher ground when they feel an earthquake or see the ocean quickly recede.
"If you move quickly away from the beach you survive; the further you move, the better off you are," he said.
Tsunamis have hit the area before, in 1812 in Santa Barbara and in 1927 in Lompoc, according to the report, which is slated to be published in Geophysical Research Letters early next year. It includes written accounts of eyewitnesses to the 1812 event, who told of the sea rising "like a high mountain" and said they had to move more than a mile and a half inland.
Just a few years ago, Synolakis said, tsunamis were thought to be solely the product of earthquake-produced waves that travel thousands of miles before hitting land. For instance Alaska earthquakes triggered a tsunami that killed 140 people in Hilo, Hawaii, in 1946 and another in 1964 that hit Eureka.
Those assumptions were shattered in a tragic way in 1998 when an earthquake off Papua New Guinea triggered an underwater landslide and resulting tsunami that killed 2,000 people.
Synolakis, who led a National Science Foundation study of the Papua New Guinea tsunami, said improved news coverage of natural disasters around the world has helped researchers discover that tsunamis are more common than they had thought.
Under the direction of the National Oceanic and Atmospheric Administration, researchers around the country are analyzing tsunami risk in coastal areas. Synolakis' team also worked with the state office of emergency services to produce tsunami inundation maps of California coastal areas.
"The state been fairly proactive," Synolakis said, adding that lifeguards, for instance, have been informed about tsunami warning signs and how to respond to them.
Although Synolakis said he is optimistic Southern Californians can get out of the way of a tsunami, he added that the densely inhabited coastline has a challenge less developed areas lack.
"Cars become projectiles," he said, adding that a small, 8-foot tsunami in Mexico was enough to move an RV a quarter of a mile inland.
"But if people are well educated .. and do not panic, people can be saved," he said. |
