The day the earth shook
October 2, 2008 · Updated 2:17 PM
SNOQUALMIE VALLEY - It may have lasted only seconds, but last Wednesday's 6.8-magnitude earthquake left a scar that will be visible for years to come.
What seismologists are calling the Nisqually Earthquake buckled roads, shifted buildings, lowered cities and toppled shelves. Cleanup is ongoing, and building inspectors are busy examining local foundations and walls.
The city of Snoqualmie seemed to sustain the bulk of the damage found in the Valley. Just west of the city, the quake opened a 100-foot-long fissure in State Route 202, and nearby steep slopes threaten to cover the highway with landslides. Inside the city, crews worked around the clock to repair two broken water mains, with one of the breaks causing several cracks in the road to snake along and across the intersection of River and Park streets.
Snoqualmie's City Hall suffered major damage in the earthquake, and officials said Tuesday the building will be demolished. Damage was also reported at the City Hall and fire-department building in North Bend, while in Carnation, no problems were found at city facilities but King County has closed the Tolt Hill Bridge indefinitely because of damage.
Shortly after 10:54 a.m. Wednesday, Feb. 28, 33 miles below the surface of the earth, a temblor struck the Puget Sound region. Its epicenter was calculated to be 11 miles northeast of Olympia, near the Nisqually River delta.
Its shockwaves were reportedly felt as far away as Salt Lake City, British Columbia and Oregon. After several minutes of checking and double-checking their figures once their buildings had stopped swaying, scientists said the earthquake had a magnitude of 6.8, making it the second-most powerful quake of the past 50 years.
Gerick Bergsma, a research assistant at the University of Washington seismology laboratory, said the quake was the result of one continental plate slowly overlapping another.
"The main driver of the seismicity that we're seeing is the subduction zone," he said, explaining how the Juan de Fuca plate is being pushed underneath the North American plate. "The [Juan de Fuca] plate is dipping down into the mantle. That puts it under a lot of pressure and increases the temperature."
He said the pressure is forcing the Juan de Fuca plate to bend, creating enormous tension in the rocks that make up the plate. And with the increased temperatures, the mineral content of the rocks is changing, too. After enough pressure is built up, it has to be released.
"It finally reaches a breaking point," Bergsma said.
One of the Valley's most important arterials, State Route 202, will be closed for a year - maybe more - because of earthquake-induced damage. A 100-foot crack, 3 inches wide, was opened up near the center of the roadway, and several, smaller perpendicular cracks have been found.
The road is closed from milepost 24.18, near 372nd Avenue Southeast to milepost 25.98, near Snoqualmie Falls Park. There is still access to the park and the Salish Lodge and Spa. Melanie Moores of the state Department of Transportation Northwest Region, which includes Snoqualmie Valley, said drivers should use Interstate 90 to get to Fall City from Snoqualmie.
"We have it chained off," she said of the area. "We do not want any traffic going through there. The slope is very unstable."
Workers have filled the large crack to prevent water from seeping through and loosening the soil underneath, which could send part of the roadway sliding off the hill.
"[Water] just puts weight there and could eventually put the whole thing down there," said Snoqualmie City Administrator Gary Armstrong on Friday, motioning over the side of the hill. Armstrong was part of a contingent of city officials showing 8th District Rep. Jennifer Dunn damage caused by the Nisqually Earthquake.
There is also the threat that part of the hill above the highway could slide down and cause it to be impassable, Moores said. The most recent landslide occurred two years ago. In 1999, DOT placed a weight restriction on the road, but that was eventually lifted after several months of dry weather. The wet winter of 2000 saw more slide activity, but it happened on the other side of the highway and did not pose a danger to SR 202, Moores said. According to 1999 DOT figures, 9,000 motorists travel through that section of the highway a day.
Permanent fixes for the highway have been sought, but landslides during the past two years forced engineers to scrap their original project and think of a new one. Construction was slated to begin next year on a new fix, but Moores said the earthquake "has changed our plans."
With President Bush's declaration that King County and other Western Washington counties are a federal disaster area, Moores said the state will have the opportunity to seek federal funds to help pay for repairs, and DOT engineers will begin deciding how to conduct those repairs this week.
"We're going to let things calm down a bit, too, because with an earthquake, you'll see resulting symptoms for the next week," she said.
City Hall to be torn down
A red sign and yellow tape warn people to stay away from City Hall on River Street in Snoqualmie. The building, which was remodeled in the 1990s and serves at City Council chambers, received the hardest blow from Wednesday's earthquake.
Jim Tinner, building official and code enforcement officer for the city, said the quake caused the historic building to twist about its axis, creating several cracks in its north, west and south walls. Inside the building, it's possible to see daylight through one crack.
"It tried to rotate, and in trying to rotate, there are no systems to stop that," Tinner said. "The [wooden portion of the building] tried to support the bricks, but it failed."
Cracks run from top to bottom where a pilaster on the north wall is attached to the building. The pilaster at one time served as a chimney, and it helps support the building's second story. The strain from the weight the pilaster is still supporting has caused it to bow outward slightly.
On Friday, the mayor's office inside was strewn with fallen books, and framed certificates hung lopsided on walls. The front door could not be opened because the lock was shaken apart during the earthquake. And new cracks can be seen on the sidewalk around the building.
Days later, after engineers hired by the city's insurance carrier inspected City Hall, officials were told the bad news: The building needs to be demolished.
"I was devastated yesterday when I found out it had to come down," said Snoqualmie Mayor Fuzzy Fletcher on Tuesday. He said the building was valued at about $350,000.
Armstrong said during the subsequent inspection, engineers found the damage was too severe to fix.
"They didn't believe it could be saved the way it is now," he said, adding that a fence would be erected around the building to keep people from coming too close to it as city officials and City Council members decide what to do.
"We're going to take some time to make a decision on what we should do with the site location and what we should do from here," Armstrong said.
A block away, at the intersection of River and Park streets, an 8-inch water main broke last Wednesday, creating a 100-foot crack that creeps along the northern edge of the intersection, near the river, and several cracks that cross the street. Another main break was reported at two 6-inch pipes near Railroad and Meadowbrook avenues. In all, the breaks cost $10,000 to fix.
City crews worked Wednesday afternoon into Thursday morning to fix the breaks, which depleted the city's reservoirs that supply water to the historic section of town. To prevent residents from drinking or using possibly contaminated water, a boil-water order was issued, and people were advised to conserve water. Shortly after the earthquake, Fletcher declared a state of emergency in the city.
"The boil-water issue is pretty much a precautionary measure just because of the opportunity that contaminants had to get in there,"