Wide Ranging Efforts are bearing down on what's certain to be a deadly encore for coastlines on the Pacific Rim.

Terry Thompson vividly recalls the tsunami that slammed into the Newport shoreline on a moonlit night 34 years ago. A 17-year-old high school student at the time, Thompson witnessed the initial 10-foot wave as it raced ashore at 11:35 p.m. March 27, 1964. “My family lived on a cliff, and we were able to safely see it,” said Thompson, now a commercial fisherman and state legislator. “It was just like a huge high tide that pushed up the boats, then rapidly went back down.”

A few miles north on Beverly Beach, the wave brought tragedy to a Tacoma couple when all four of their young children were swept from the family’s camping spot and drowned. Along the rest of the Oregon coast, cars, motels, bridges, houses and sea walls were destroyed.

But Crescent City, Calif., about 20 miles south of Oregon, fared even worse. Days later Thompson saw from a fishing boat the devastation in the coastal community, where the tsunami killed 11 people and caused about $15 million in damage. “It was hard to believe that it was the same tsunami that came to Newport,” he said. “It was like a bomb went off. There was just one little building left standing near the water in the downtown area.”

Unlike Thompson, most Oregonians have not seen firsthand a tsunami or the devastation it can bring. In the past two decades, Oregonians have experienced erupting volcanoes, earthquakes, landslides and floods. But a tsunami -- a series of waves primarily generated by undersea earthquakes -- has been an underrated hazard in the Northwest, scientists say.

Because of the danger, a joint federal-state effort called the National Tsunami Mitigation Program is beginning to make waves of its own in an effort to better warn and prepare people for the hazard. Three federal agencies -- the National Oceanic and Atmospheric Administration, the U.S. Geological Survey and the Federal Emergency Management Administration and the five Pacific states are participating in the program. It includes:

• Developing and deploying special sensors in the deep ocean that would provide fast, accurate information about the potential size and speed of a tsunami.
• Upgrading seismic networks so that they more accurately pinpoint tsunami-producing earthquakes and allow better communication among the different networks.
• Mapping where tsunamis might inundate coastal communities so planners can determine where emergency facilities; and evacuation routes should be placed.
• Educating the public about the danger and how to prepare for it.

Throughout history, tsunamis have occurred repeatedly on the Oregon coast, and they undoubtedly will strike again, scientists say. The most recent significant tsunami, in 1964, was generated by a magnitude 9.2 earthquake that rocked south-central Alaska, causing 125 deaths, 110 of those from the deadly wave.

In addition to the threat from distant earthquakes in Alaska and elsewhere in the Pacific Basin, researchers have found during the past dozen years that Oregon has been hit every few hundred years by huge tsunamis generated by quakes just off the coast in the Cascadia Subduction Zone. The area is where the Juan de Fuca Plate plunges underneath the North American Plate. If the tectonic plates lock up, the energy eventually is released in a tsunami-producing earthquake.

The last subduction zone quake -- an estimated magnitude 9 -- occurred about 9 p.m. January 26, 1700, studies have shown. In addition to a 30-foot-high tsunami that smashed into the Oregon coast, 6-foot-high waves reached Japan, damaging coastal villages.

Similar subduction zone activity produced the two largest earthquakes ever recorded: the 1964 magnitude 9.2 quake and tsunami that hit Alaska’s Prince William Sound and the magnitude 9.5 quake and tsunami that rocked Chile in 1960. The Chilean tsunami killed more than 1,000 people in Chile, 61 in Hawaii and 199 in Japan.

More recently, a magnitude 7.0 earthquake on July 17 at Papua, New Guinea generated a tsunami that killed more than 3,000 people. Although the area also is the site of a subduction zone, a five-member scientific team speculates that the deadly sea waves were the result of an undersea landslide caused by an earthquake centered inland.

A Monitoring Network

After the 1964 quake, a warning center was set up in Palmer, Alaska, to alert Oregon, Washington, California, Alaska and British Columbia to tsunamis. Another warning center in Hawaii handles tsunami alerts for that state and the rest of the Pacific Rim. The centers monitor offshore quakes with a network of seismic stations, which show the size and location of the quakes.

“If the earthquake is 7.1 or greater, we’ll issue a warning,” said Thomas J. Sokolowski, the geophysicist in charge of the West Coast and Alaska Tsunami Warning Center. “After we issue the warning, then we have about 80 tide gauges that we look at that would confirm the existence of a tsunami. If that wave is very large, then we would expand the warning. If it’s negligible and not going to cause any damage, then we would cancel it.”

Sokolowski said only about ten warnings have been issued in the past decade, but the six-member staff responds each year to about 250 to 300 earthquakes that activate the center’s alarm system. The response time from the start of an earthquake to the issuing of a warning averages about ten minutes, he said.

Although scientists understand a great deal about tsunamis, they are only able to have a rough idea about how big or destructive one may be. In the deep open ocean, a tsunami is less than a few feet high at the surface and is unnoticed by ships, even though the waves can travel at nearly 600 mpg. A tsunami’s wave energy extends from the surface to the ocean floor. As it approaches a shoreline, the wave energy is compressed into a shorter distance, resulting in higher, life-threatening waves.

New Instrument 

But estimating the size of a tsunami may be easier with a new detection instrument being developed by NOAA’s Pacific Marine Environmental Laboratory in Seattle. Frank Gonzalez, the laboratory’s tsunami program leader, said the tsunami detection system consists of three parts: a pressure recorder on the seafloor, a buoy on the surface and a satellite communication system.

When a tsunami passes through the ocean, the bottom instrument measures changes in the pressure of the water overhead. “This is an amazing instrument,” Gonzalez said. “It has a sensitivity to detect a 1 millimeter change in sea level when a tsunami passes overhead. We have great confidence this instrument will detect any tsunami out there that could conceivably be of any danger to anybody.”

Using acoustic signals, the seafloor sensor sends its information to the buoy about a mile away on the surface. That’s the challenging aspect of the system. “It turns out to be very difficult to get that data from the bottom of the ocean to the surface,” Gonzalez said. “We’ve developed several prototypes and tested them off the Oregon and Washington coast and in the Gulf of Alaska. But we still have a ways to go to make them reliable. I have no doubt we’ll be successful.”

Once the buoy receives the information, the data would be transmitted immediately by satellite to the tsunami warning centers in Alaska and Hawaii. The goal is to have a network of six tsunami detection buoys in place in two or three years. Three of the instruments would be placed along the Aleutian Island chain and two would be placed off the Oregon-Washington coast. A sixth buoy would be at the equator to detect wave energy generated off Chile and Peru.

Such a network would help eliminate the occasional false alarms issued by the warning centers, which have to rely on the indirect measurements of seismometers and tide gauges. For example, in October 1994, a magnitude 7.9 earthquake hit the Kuril Islands about 650 miles north of Hokkaido, Japan’s northernmost island. Japan reported a tsunami up to 10 feet high, and the Pacific Tsunami Warning Center in Ewa Beach, Hawaii, alerted the West Coast. Schools in Curry County and Cannon Beach closed early, and beaches were evacuated. Ships were told to stay out to sea. But the wave was only about 6 inches high. “False alarms make us strive toward doing our job better,” Sokolowski said. “Computer models are being developed that are going to help us have an idea how big a tsunami is going to be. But if I’m going to err, it’s always going to be on the side of safety if there’s a potential for deaths and destruction.”

A Role for Computers

Computers are playing another important role in preparing communities for a tsunami. Oregon researchers are producing maps showing how tsunamis could flood coastal communities. They include Antonio M. Baptista and Edward P. Myers III at the Oregon Graduate Institute, Robert A. Kamphaus with the Pacific Marine Environmental Laboratory’s new Center for the Tsunami Inundation Mapping Effort in Newport and George R. Priest of the Oregon Department of Geology and Mineral Industries.

Two years ago, the state geology department released 58 maps showing the tsunami inundation zone along the Oregon coast. Each map has a line that shows how far inland and uphill a tsunami caused by a magnitude 8.8 offshore earthquake is expected to go. The maps were developed to implement a law enacted by the 1995 Legislature to restrict construction of critical buildings, such as schools, hospitals and fire stations, in low-lying areas where they might be hit by a tsunami.

The latest maps, however, are more comprehensive and will help emergency managers identify such things as evacuation routes. “These new maps show in far more detail and with more certainty what the actual tsunami flooding would be for a range of earthquakes,” Priest said.

In July, the geology department released a map of tsunami hazards for the Seaside-Gearhart area. It shows how three different tsunamis might affect the area and outlines the areas flooded by the 1964 tsunami. Similar maps previously were issued for Siletz Bay and Yaquina Bay. New maps are being developed for the Warrneton-Astoria area, Gold Beach and for the Willapa Bay-Long Beach Peninsula area and Grays Harbor on the Washington coast.

The National Tsunami Hazard Mitigation Program also is upgrading earthquake monitoring equipment to provide more accurate detection of offshore earthquakes and measure their sizes. Three new seismic stations are being considered for Oregon: one west of Portland, one near North Bend and one just north of the California state line, said Stephen D. Malone, a research professor in the University of Washington’s Geophysics Program. “Their primary purpose would be to provide date rapidly for anything off the coast,” he said.

About $800,000 of the tsunami program’s money is going toward the six seismic networks operating along the West Coast to improve communications among one another. Malone, who is with the Pacific Northwest Seismograph Network that monitors earthquakes in Washington and Oregon, said a computer system called "Earthworm" allows the networks to exchange data immediately.

Eddie Bernard, a tsunami expert and director of the Pacific Marine Environmental Laboratory, said the upgrading of the seismic networks is vital. “This information needs to be instantly accessible to everyone,” he said, “and the places we want to share it with are the tsunami warning centers to quickly give them the best information we can.” 

Also see: Tsunami Facts, by Richard L. Hill of The Oregonian Staff

Richard L. Hill covers science for The Oregonian’s Health/Medicine/Science team. He can be reached at (503) 221-8238, or e-mail at richardhill@news.oregonian.com.