OREGON STATE UNIVERSITY

Preparation key to Northwest surviving a tsunami disaster

01/13/2005

CORVALLIS - For a preview of a tremendous earthquake and tsunami in the Pacific Northwest, take a look at Southeast Asia's recent disaster, an Oregon State University natural hazards expert said.

"Geologically-speaking, Sumatra is directly analogous to the Oregon Coast," said Jim Good, an OSU professor of oceanic and atmospheric sciences and director of OSU's Marine Resource Management Program.

In the Pacific Northwest, the Cascadia Subduction zone, a 600-mile long underwater fault zone that runs from Cape Mendocino in California to central British Columbia, is a virtual twin to the 600-mile long fault that snapped recently offshore in Indonesia.

"We could expect a similar 600-mile long and 50-mile wide break zone here; they are very similar regions," said Good, who spent more than 15 years with OSU's Oregon Sea Grant in coastal hazards management, including work on reducing earthquake and tsunami hazards in Pacific Northwest ports and harbors.

"Earthquakes and tsunamis pose significant threats to Pacific Northwest coastal port and harbor communities," Good said. "We have done as good a job in hazard preparedness as any coastal state in the U.S., but we have to continue to educate people and improve all aspects of readiness.

"This is the absolute, ultimate, teachable moment," Good said. "But that education work needs to be sustained into the future too, and that is the real challenge.

A large earthquake along the coast could trigger multiple landslides, knock-out utilities such as power and telephone services, as well as buckle roadways and runways. A subsequent tsunami, which could hit the coast in as little as 15 minutes following a local quake, could build waves topping 30 feet hitting the coast at speeds of 20 miles per hour or more.

In some onshore areas, primarily along the northern Oregon Coast, the land could drop two to three feet, increasing the risk from high water, while in other areas, there could be a rise in elevation.

The walls of water could threaten the coast for eight hours or more, with some of the larger waves actually occurring hours after the first wave hits the shore, Good said. In addition to damaging structures and other improvements, the flood of seawater could have profound effects on the natural environment, destroying habitat for marine and land plants and animals.

As the water rushes back to sea, logs, rocks, beams, even materials such as oil, fuel and other toxic debris could rush back with it, causing further damage. Dock facilities, bridges, ships and boats, as well as coastal developments could sustain significant damage and the chance of loss of life is high.

"Think of the video footage you've seen on TV recently," Good said. "That's what it could be like here."

While scientists and emergency managers are already planning a "Tsunami Summit" this spring to build on progress already made on earthquake and tsunami science and readiness, researchers and community leaders shouldn't delay work to continue to improve safety in the coastal regions, he said.

"What needs to be done is to take stock of the progress that has been made, based on earlier recommendations, see what work remains to be done, and get to work."

Good said a great deal of progress has already been made along the Oregon coast. Tsunami hazard zones, evacuation routes and safe gathering spots are clearly marked by distinctive blue and white signs. Government, business and local residents have worked to craft recommendations to save lives and limit property loss, including warning systems, critical facility relocation, structural retrofitting, and emergency operations plans targeted for specific sectors of the community.

On a statewide level, the Oregon legislature will do doubt be taking another look at tsunami preparations, Good said. For example, state officials will analyze the failed 2003 bill drafted by Springfield legislator Sen. Bill Morrisette.

That proposal, Senate Bill 650, would have required the Oregon Office of Emergency Management to enhance the region's tsunami warning information and evacuation plans, requiring lodging facilities to provide information on tsunami hazards and response to their guests.

"Inherent problems lie in minimizing the risk on one hand, and hyping it on the other," Good said. "Keeping the 'scare factor' down, while at the same time keeping up awareness and readiness is an ongoing challenge."

While geologic records document that 300 years ago there was a great earthquake where huge tsunamis slammed into the Pacific Northwest coast, no researcher can say when another disaster will strike - whether in the next hour or the next 1,000 years.

"It's just human nature. It's difficult to get excited about something that might happen 1,000 years into the future. Although I never quite made Eagle Scout, I do remember the motto - 'be prepared.' We can do that."