The Nisqually Earthquake: Ten Years After

Feb 28, 2011

Ten years ago today, the Puget Sound region was rocked by a powerful earthquake. The magnitude 6.8 quake brought down brick facades, damaged Seattle’s waterfront viaduct and split the Capitol dome in Olympia. The ground shook for about 45 seconds and tremors were felt as far away as Salt Lake City.

The Nisqually Earthquake left in its wake  ...

  • as much as $4 billion in damages
  • about 700 injured
  • one dead from a stress-related heart attack.

Back then, Stephen Malone was head of the Pacific Northwest Seismic Network at the University of Washington.

“It was a repeat type of a quake that we’d had twice before in relatively recent history; 1949, near Olympia and 1965 near Tacoma.”

Professor Malone says all three quakes were of a type that are centered deep underground -- the Nisqually quake’s epicenter was about 32 miles below the surface – so they’re usually not highly destructive. Those earlier quakes were deadlier – eight died in 1949 and the 1965 quake killed seven.

John Schelling, who runs the earthquake program for Washington State Emergency Management division,  says there was a reason for the Nisqually quake’s lower death toll.

“Schools had been retrofitted. Water tanks that were unstable and posed a threat were removed. An extensive amount of outreach and education to raise awareness about the risks that we face in Washington State was completed.”

What's Happened Since 2001?

In the last 10 years, efforts to prepare for the next quake have accelerated, including ...

  • The state has passed out more than $50 million federal dollars for nearly four dozen seismic upgrade projects.
  • Highway officials have retrofit close to 250 bridges.
  • Communications between emergency responders have been upgraded.
  • Researchers have tripled the seismic sensors, as well as the territory they monitor.

But experts say we have yet to have “The Big One.” And the recent quake in Christchurch, New Zealand could foreshadow the threat in the Pacific Northwest. Retired U-Dub professor Stephen Malone points out that was a shallow quake that did a lot of damage because it was close to the surface. There are some differences, he says. But …

“The fault system there is fairly complicated, similar to faults that we have here in this area. And indeed there may turn out to be closer parallels than we now feel.”      

Those shallow quakes occur less frequently than the deep ones like the Nisqually quake; about every thousand years.

Geologists estimate the last one rattled Puget Sound about 1,100 years ago.