Uncharted Waters

Communities, engineers and scientists prepare for the next tsunami
Simulated tsunamis crash into scale model buildings at OSU's O.H. Hinsdale Wave Research Lab, the nation's largest tsunami test facility. Engineers have run tests with the Oregon coastal communities of Seaside and Cannon Beach (Photo: Frank Miller)

Simulated tsunamis crash into scale model buildings at OSU's O.H. Hinsdale Wave Research Lab, the nation's largest tsunami test facility. Engineers have run tests with the Oregon coastal communities of Seaside and Cannon Beach (Photo: Frank Miller)

It may come like it did the last time, in the middle of a cold and blustery January night. Suddenly the ground will begin to shake, windows will shatter, bridges collapse, the electricity will go out and parents will frantically try to find a flashlight and dig sleepy kids out of bed, ignore everything else and run – because they know they only have minutes before the water arrives.

Even worse, it may come on a warm and breezy summer afternoon in July, when tens of thousands of visitors fly kites, build sand castles and play fetch with their dogs on one of the most beautiful stretches of coastline in the world. The rumble and shaking on the crowded beaches will quickly be replaced by a receding shoreline as the water eerily slides away, and people will start to run, anywhere they can, to get to higher ground – because they know the water will soon be coming back.

It will be scary, it will be destructive, and it’s going to happen, reasonably soon. People will talk for generations to come about the great subduction zone earthquake and tsunami of ____. Fill in the blank with a date; science can provide some guidance, but no one knows for certain when it will be.

Pat Corcoran, a coastal hazards outreach specialist with Oregon Sea Grant, is mindful of these risks and calls the disaster that’s waiting to happen “arguably the greatest recurring natural hazard in the lowest 48 states.” That’s about right. Subduction zones – like the Cascadia Subduction Zone that lurks just off the coast of the Pacific Northwest – produce the most massive earthquakes in the world. And their “up and down” ground motion triggers tsunamis, one of the most deadly ocean wave events in the world.

Like Clockwork

The problem is, at least in the United States, these events don’t happen very often. In fact, until the mid-1980s, scientists didn’t think great earthquakes and tsunamis were caused by Pacific Northwest fault zones. Then some pioneering research by the U.S. Geological Survey, Oregon State University and others began to unravel some ancient mysteries. Scientists found that not only do they happen here, they occur pretty regularly, about every 300 to 500 years on one part or all of the Cascadia Subduction Zone, which runs 700 miles from Cape Mendocino in California to Vancouver Island in Canada. The last event was pinpointed because the enormous tsunami it created raced all the way across the Pacific Ocean to Japan, where written records were kept. It occurred here about 9 p.m. on Jan. 26, 1700.

“The Native Americans at the time of the last subduction zone earthquake in 1700 had a rich oral history surrounding earthquakes and tsunamis,” Corcoran says. “One tradition encouraged people to weave long ropes. That way, the saying went, following the earthquake a person could tie one end of the long rope around a tree and the other onto their canoe in order to ride out the tsunami waves.”

It’s now 2010, more than three centuries later. The newest studies produced by Chris Goldfinger, an OSU marine geologist and one of the world’s leading experts on the Cascadia Subduction Zone, indicate that there’s a 37 percent chance of a partial rupture of the zone within the next 50 years, an event that could be similar in magnitude to the earthquake just experienced in Chile.

“Perhaps more striking than the probability numbers is that we have already gone longer without an earthquake than 75 percent of the known times between earthquakes in the last 10,000 years,” Goldfinger says. “And 50 years from now, that number will rise to 85 percent.”

So it’s coming soon, possibly tomorrow. Possibly in 10 years. A better than one in three chance within the next 50 years. But no one knows for sure, and that isn’t going to change. With existing science, earthquakes cannot be predicted with precision; we can only prepare.

But Are We Prepared?

A few years ago, local residents in Cannon Beach, Oregon, were pondering that question, as they followed the developing science on subduction zone earthquakes and worked with officials from the Oregon Department of Geology and Mineral Industries on evacuation maps for the anticipated tsunami.

Preparation for a tsunami, in this context, would be defined as people knowing what to do, where to go, getting to high ground and having the time to do it. Jay Raskin, a longtime resident, community leader and local architect, didn’t like what he was hearing.

“Around then, the scientists were describing and updating the potential risks for an earthquake and tsunami caused by the Cascadia Subduction Zone,” Raskin says. “We talked about the distances we needed to go, how high the water might get, where high enough ground was, the bridges that probably would be destroyed.

“And then we’re thinking, oh darn, this strategy of getting to high ground might not work for everyone,” he says. “For some people there just might not be enough time. We needed another option.”

Then Hurricane Katrina struck, and another lesson was offered to the Cannon Beach residents. In the aftermath of the storm, not only had the devastation of coastal communities been enormous, but there was no functioning city government, no working facility to help rebuild.

A Sunny Day at the Beach

Cannon Beach is a small coastal community a little south of Seaside, Oregon. It’s butted up against coastal headlands and stretches for several lovely miles along the Pacific Ocean coast. Most of its 1,700 residents live within a few blocks of the beach, and about half of them, and 75 percent of the businesses, reside within a tsunami inundation zone. But it could be much worse. On a peak summer day, up to 12,000 people may crowd the beaches around Cannon Beach. The city presents a microcosm of an issue that affects a vulnerable shoreline about 900 miles long.

Tsunami Evac Building on Stilts

Tsunami Evacuation Building

In addition to a tsunami response plan, the city needed a new city hall. So Raskin and others had an idea. Why not build a structure that could survive a tsunami, stand above the incoming water, give local residents and visitors a safe place they could run to on short notice, save many lives, and also serve as a base of operations after the disaster to help the city recover and get back up and running?

It was the comparatively new concept of “vertical evacuation” to escape a tsunami, and it was a good idea. Two problems: No structure of that type had ever been built in the United States, and in the few places in the world where such structures had been built, such as Japan, none had yet experienced a tsunami. So as an engineering challenge, this was literally uncharted water. Also, it would cost more. A design has now been created for a new 10,000-square-foot structure, and it’s estimated to cost around $4 million, about double the cost for a more conventional building.

But the issues are real, and the Cannon Beach residents knew it. They had watched the devastation from the Sumatra earthquake and tsunami in 2004, where 230,000 people died, most of them not from the earthquake, but rather the tsunami. The geology of that region is nearly identical to the Cascadia Subduction Zone.

“After the Sumatra earthquake, I saw on television this scientist from Thailand, who had tried years before to convince local authorities to put in warning buoys, but no one did anything,” Raskin says. “He was in tears, he considered it a personal failure.”

“That struck me hard,” he says. “I was a city councilor at the time, I knew we faced the same issues, and I didn’t want that to happen here, to have to say years later that we knew all about this but didn’t do anything.”

For a nearby subduction zone earthquake like the one expected on Cascadia, warning buoys are not really the point. The earthquake itself will give any informed person all the warning they need, and only minutes will be available to get to high ground before the water starts rising and just keeps coming – an event Raskin likens to “a sneaker wave on steroids.”

The Real Enemies: Time and Transportation

So last May, at the Hinsdale Wave Research Laboratory at OSU, a small model of the proposed new city hall building at Cannon Beach was being hit by simulated tsunamis repeatedly, to help address some of the questions. It’s not fancy, essentially a square structure on stilts, but very strong and with a sturdy foundation. But how strong is strong enough? What will be the effect of debris, such as floating cars, slamming into the pillars? OSU was helping Cannon Beach to answer those questions, in research supported by the National Science Foundation.

“We have to know just how strong this building has to be, so the community can build something that will work, but at the same time keep costs as low as possible,” says Dan Cox, an OSU professor of coastal and ocean engineering. “Some buildings may slow the force of the waves before they hit, for instance, and other debris may cause additional impacts.

“In engineering, this is new territory. We’re just scratching the surface of everything we need to know, but these studies should give us a higher degree of confidence in what we build, and in the process our students are learning how to build structures of this type for the future.”

Other work to aid Cannon Beach is also under way at OSU. Harry Yeh, the Edwards Professor of Coastal and Ocean Engineering, one of the world’s leading experts on tsunamis, has been involved with the community for years to help it address concerns, design the new structure. He is now working on an evacuation plan.

“We know we can build a structure that will survive an earthquake and tsunami, and could serve as an emergency shelter,” Yeh says. “Strong, reinforced concrete buildings can stand up to that, we saw that in Indonesia in 2004. And pretty much everyone agrees this structure would be good to have. But it will cost more, so to make this feasible, we have to figure out the best way to balance cost and function.”

The initiative in Cannon Beach is unique, and if implemented, will be the nation’s first structure designed specifically to survive an earthquake, resist the forces of a tsunami, and hopefully save lives. OSU has worked closely with state and federal agencies, as well as private companies, to make this happen. The result could form a model, both physically and inspirationally, for many other coastal communities that face similar concerns. And community support so far, Raskin says, has been reasonably strong. People have raised some fair and intelligent questions, but almost no one is advocating the status quo. Funding support may ultimately be sought from both local, state and federal levels and the private sector.

But Cannon Beach is one small town, on one short section of beach. The earthquake on the Cascadia Subduction Zone, when it happens, could be one of the great geologic events in world history, affecting three states, some of British Columbia, major cities and many millions of people. That’s a big problem, which goes well beyond the issue of the expected tsunami.

Living in the Quake Zone

Are we prepared?

OSU researchers are doing what they can. Earthquake and tsunami simulation modeling is being done in several Oregon sites. A course has been created and is being taught on “living with earthquakes.” OSU researchers have worked with the Oregon Department of Transportation to simulate tsunami loads on coastal bridges. Scientists have gone to Sumatra, to American Samoa, to Chile, to the sites of all the recent major subduction zone earthquakes and tsunamis in recent years to learn whatever might help.

To further explore these questions, Scott Ashford and Solomon Yim from OSU were part of a group supported by the National Science Foundation who went to Chile this past spring after the February 8.8 magnitude earthquake — also on a subduction zone similar to that of the Pacific Northwest. Yim, a professor of civil engineering, led a team of tsunami, structural and geotechnical engineers and surveyed damages to ports, coastal buildings and bridges. Ashford, professor and head of the School of Civil and Construction Engineering at OSU, said the group wanted to learn as much as possible about what had happened, what worked and what didn’t.

Chile, even more than the United States, has experience with subduction zone earthquakes. They happen with more frequency there, and a massive 9.5 event in 1960 was the largest earthquake ever recorded. Because of that, they have modern and aggressive building codes, as good or better than those in the Pacific Northwest, and much better than those used when many of the urban structures in Oregon and Washington were built 30 or more years ago.

“Part of what was striking about the Chile earthquake was the geographic extent of the damage. It was spread out over an area essentially from Seattle to Medford here in the U.S., and from I-5 to the coast,” Ashford says. “The damage itself, as you often see with earthquakes, was variable. Some areas were very hard hit, others much less.”

Chile, Japan and New Zealand – like the U.S., all situated on the notorious “ring of fire” around the Pacific Ocean – have some of the best seismic design standards in the world, Ashford adds. Engineers in Chile were able to observe certain types of architecture, often square, unimaginative buildings, that tended to resist damage much better than more innovative and irregular designs. But it still wasn’t good enough.

“In Concepcion, all the bridges from the south were collapsed or out of commission; people were cut off,” Ashford says. “You would see people living in tents, staring at the building they used to live in but afraid to enter it even for a few minutes to get their belongings, fearing it would collapse. And of course in the areas hit by the tsunami, the damage was just devastating; it was really heartbreaking.”

Engineer for Resilience

Oregon and Washington, Ashford says, face even greater devastation in the future. “We’re going to get hit worse than Chile did; I suspect much worse. We have many large buildings in our cities that were built in the 50s, 60s and 70s that will not do well in the earthquake.”

A prime lesson Ashford says he took away from the recent Chilean experience is to preserve the lifelines: electricity, gas, water, communication and transportation, as well as critical facilities like hospitals, fire stations and schools.

“What we need here is resiliency, to provide the infrastructure for rescue, relief, and recovery efforts that will enable Oregon to bounce back from such a disaster,” Ashford says. “Like the proposed city hall at Cannon Beach, that will save lives and give you something to build around.”

Ashford sees OSU as the logical institution to lead that effort. Working with the Oregon Department of Transportation, the National Oceanic and Atmospheric Administration, utility companies, cities, and other agencies, OSU has the engineering and scientific and management expertise to help coordinate preparation for a major disaster, to build in that resilience that can literally mean the difference between life and death after a major disaster.

Fortunately, there may still be time to accomplish a great deal. Oregon Sea Grant’s Pat Corcoran noted that “we are the first modern generation to intellectually understand that we will experience great earthquakes and tsunamis.” The next event could happen tomorrow, but it also might not be for 30, 50 or 100 years. If so, that could offer a pretty good window of opportunity for public education and outreach for both local residents and tourists, community preparations, new and better building designs, sustained research programs, replacement of aging and dangerous structures. All of that is possible and many of these issues can be addressed if everyone involved — government, universities, agencies, people — work together to create a safer future.

But there’s a lot to do and only a limited time available to do it. Because a massive earthquake is coming that will destroy homes, buildings, roads, bridges and infrastructure across the Pacific Northwest. And a massive tsunami is coming with waters that will sweep ashore with deadly force. They are coming. We know that.

Are we prepared?

No.
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See a, April 2012 video about tsunami preparedness by Tom Bearden, National Public Radio.

Watch Risky Business in the Northwest on PBS. See more from PBS NewsHour.

 

For information about supporting research and teaching through faculty endowments, contact the Oregon State University Foundation, 1-800-354-7281 or visit CampaignforOSU.org.

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