Recent Stories with tag fault

Steve Malone, on Mount St. Helens with Scooter the seismo-dog

"The longer it's been since the last earthquake," said Steve Malone, brightly, "the sooner it is 'til the next one." We were in his office at the University of Washington--he's retired from full-time seismologizing, but still spends unpaid hours on campus answering questions from pesky bloggers, even if they're fueled by sensationalist speculation about more frequent quakes.

He refocused my question away from end-time paranoia toward common sense acceptance: "We have several of these faults: there's the Seattle Fault, and there's one down in the Tacoma basin, one up at Everett and Whidbey Island…so if you say, we've got eight or ten of these faults, even if the earthquakes go once every thousand years, you sum them up, you could have something every few hundred years of some consequence," explained Malone. "You don't know, it could be 500 years, or it could be tomorrow." 

He also assured me that, incredible as it seems, it's perfectly plausible that the recent Baja quake could have generated waves at a Ballard pool. "Large earthquakes generate big surface waves, and big surface waves generate a bit of a tilt as they go through. If a body of water's natural free period happened to be the same as the frequency of those surface waves, then after a couple of cycles you might see it get built up enough," said Malone. "The motions of surface waves can be on the order of centimeters. We just don't feel it because it's very slow." 

As an afterthought, he added: "The Denali quake of 2002--bigger than Baja [7.9] but further away--it generated a sloshing in Lake Union that damaged houseboats."

And because I had to ask: "Tunnels aren't usually an issue with earthquakes. The motion underground is less than on the surface, and they're already built to withstand the pressures of everything else."

As it turned out, we ended up talking across the breadth of Malone's career, covering volcanic earthquakes, megathrust quakes, and the mysterious Episodic Tremor and Slip (ETS). His interest in seismology developed in graduate school; he'd studied physics as undergraduate, but was not "keen on modern physics" and gravitated toward geology, then seismology. At first he enjoyed the outdoors aspects of the work, "particularly in the volcano world," but as his research progressed, he ended up in the office running computer models.

Malone on Mount Rainier

"Since I retired I get to go out and play," he said, smiling. "I volunteer for all sorts of fieldwork." He's been up on Mount Rainier working on an upgrade of instruments there, and out on the Olympic Peninsula conducting ETS studies in advance of the next appearance of the phenomenon.

"The ETS we have here are fairly regular, every 14 and a half months or so. The next one is scheduled--if you can call it that--for sometime mid-summer, maybe mid-August. We've got some experiments we're planning to gear up and get extra equipment in the ground for. There's some extra equipment out there now, running in background mode, but when the ETS arrives we'll double the equipment, trying to look ever closer at it."... (more)

You've probably spent a lot of time the past week watching video and photos, reading news articles and tweets about the Haiti earthquake. You've felt sorry for the Haitians, aghast at the scenes of death and ruin, and agonized over the condition of the survivors. But you probably haven't imagined anything remotely similar happening in the Seattle area.

Back in June 2005, a half year after the earthquake and tsunami in Southeast Asia, and over four years after the Nisqually earthquake, the Earthquake Engineering Research Institute and the Washington Military Department brought out a "Scenario for a Magnitude 6.7 Earthquake on the Seattle Fault."

That is, an earthquake slightly lighter than what struck Haiti last week, and one that would come on the Seattle Fault, which runs through south Seattle, Mercer Island, Bellevue, and the Issaquah area. It wasn't pretty: the vision of the aftermath of a 14-mile surface rupture running roughly parallel to I-90 involved over 1,600 dead, another 24,000 wounded, $33 billion of damage, and months of transportation problems for Puget Sound.

The scenario said a 6.7 Seattle Fault quake will cause damage "far worse and more extensive than seen in any earthquake in the state's history."

"The viaduct will be heavily damaged or collapse," in a way very similar to how Oakland's Cypress Viaduct pancaked in the Loma Prieta quake, Boeing Field "will experience significant liquefaction" on its runways and close for several days, the Seattle ferry terminals "will shut down for at least a week due to damage from ground failures and failure of the seawall," and we'll see a lot of the brick buildings in Pioneer Square tumble, along with a lot of the concrete warehouses south of downtown.... (more)