More natural disasters probably await nation

Planning: Volcanoes, mudflows, earthquakes and tsunamis may lie ahead, but the funds to prepare and respond are often lacking.

Katrina's Wake

September 11, 2005|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

New Orleans was warned.

Years before Hurricane Katrina's storm surge poured over their levees, the city's leaders and residents were told the dikes could not withstand a Category 4 storm. They knew the worst was inevitable, given enough time.

What other natural disasters have scientists warned the U.S. about? And how well is it preparing for the inevitable?

There's no question that public officials nationwide are looking at natural hazards in their surroundings with fresh eyes these days. They're lamenting a shift in federal funding from dealing with nature to terrorism.

And they are thinking about sites less familiar to the public than California's San Andreas Fault.

In the shadow of Washington state's Mount Rainier volcano, they're considering an eruption that would send a "lahar" - a tidal wave of cementlike mud - ripping down the populated Puyallup River Valley.

"A FEMA exercise in 2001 showed us with 5,000 deaths. We know going in there is going to be a loss of life," said Jody Woodcock, program manager in the Pierce County emergency management office.

In the Mississippi Valley, scientists worry about a repeat of 19th-century earthquakes that could level unreinforced masonry buildings across a wide region, including the cities of Memphis, Tenn., and St. Louis, killing thousands.

And in Puerto Rico, a scientist is trying to educate the public about the Caribbean's deadly history of violent earthquakes and tsunamis.

"The seismologists ... claim that we are overdue," says Aurelio Mercado-Irizarry, professor of physical oceanography at the University of Puerto Rico at Mayaguez. "This is something that is not science fiction."

The hazard tour starts in the Northwest, with Mount Rainier. An April report on America's most dangerous volcanoes ranked Rainier third, right behind Mount St. Helens and Hawaii's Kilauea, both of which are in eruptive cycles.

"It's not that it's the most likely volcano to erupt, but because when and if it does, it can impact very large populations," said Bill Steele, information director for the Pacific Northwest Seismographic Network at the University of Washington.

Rainier stands just 70 miles southeast of Seattle, visible from the city on a clear day. At 14,400 feet, its summit is colder and capped by more ice and snow than any other Cascade volcano. An eruption would melt that ice and send it raging down the river valleys in a wall of water, mud and pulverized rock.

Just such a calamity 5,600 years ago buried the White River Valley in hundreds of feet of mud and rock, filling part of Puget Sound, where the port of Tacoma stands today.

Rainier's geology reveals a series of more recent eruptions, each about 500 years apart. The last one? About 500 years ago.

But mudflows off Rainier don't require eruptions. "Just about anything can generate lahars of some size or other," said Jim Vallance, a geologist at the Cascades Volcano Observatory in Vancouver, Wash.

Water within the mountain's cone is constantly weakening its structure, making it susceptible to collapses that trigger lahars.

Down the Puyallup River Valley from Rainier, the communities of Orting, Sumner, Puyallup and Fife stand in a narrow river plain built up by ancient lahars and river sediments. For 12 years, Pierce County emergency planners have been warning about the hazard. "It's one of those low-probability, high-risk events," Woodcock said. "It's tough to get a full appreciation of what [Rainier] is capable of."

Even so, Pierce County has installed a lahar warning system that will trigger sirens if two or more sensors in the river valley go off.

"We would see probably 100,000 people evacuate from the valley," Woodcock said. That includes 40,000 residents, plus visitors and commuters, all with 40 minutes to reach high ground.

County emergency managers periodically drill school kids and work with neighborhood groups on how to move themselves up the valley slopes - a taxing, 15-minute climb from just about anywhere. "The bottom line is getting off the valley floor 50 feet, and that's going to save your life," she said. Planners expect a lahar to demolish everything in the valley and leave it uninhabitable for years.

Since Katrina, Woodcock said, phones in her office had been "ringing off the hook" with residents who want to know more. But preparedness funding has been pinched by a shift in federal priorities. "The focus since 9/11 has been so heavy on terrorism that honestly, it's my opinion that natural hazards aren't being dealt with as they could be," said Woodcock. "These are the much more common events."

Eighteen hundred miles to the southeast in Memphis, geologists are trying to get a better handle on a Z-shaped fault in the bedrock buried beneath 3,000 feet of ancient ocean and river sediments.

In the winter of 1811-1812, the fault ruptured in three violent quakes that liquefied the earth along the middle Mississippi Valley and rattled most of the eastern U.S. Buildings were damaged as far away as Charleston, S.C., and Washington, D.C.

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