Washington mega-quake presents the unthinkable
By Sandi Doughton
May 27, 2013
SEATTLE — If there were any lingering doubts that Washington state is earthquake country, a new set of scenarios developed by state and federal geologists makes it clear that no part of the state is immune to seismic mayhem.
From Tacoma to the Tri-Cities, the scenarios lay out potential impacts from a major earthquake on each region’s most dangerous fault. “Some level of earthquake damage is very plausible virtually anywhere in Washington,” said Tim Walsh, geologic hazards chief for the state Department of Natural Resources.
Though hypothetical and incomplete, the scenarios are sobering:
A quake similar to one that hit about 1,100 years ago on the Seattle Fault could kill more than a 1,000 people, injure more than 17,000, and cause $31 billion in damage to buildings, bridges, roads and utilities.
Hundreds would perish in a magnitude-7.4 quake on a fault that runs through Everett, and nearly 300,000 buildings would be damaged.
If the fault that passes near Tacoma unleashes a magnitude-7.1 quake the next time it ruptures, nearly 12,000 households could be displaced and more than 6,000 people injured.
In the Walla Walla area, a magnitude-6.8 quake on what’s called the Hite fault could leave more than 19,000 households without water and destroy more than 1,300 buildings.
The modeling, which also maps out ground-shaking, was aimed mainly at helping emergency managers get a handle on what to plan for, Walsh said.
“You can get a better idea of whether electrical substations might go down, where you might see (soil) liquefaction, where the roadways might be damaged,” he said.