Reflecting on tectonic lessons on Nisqually quake’s not-so-sweet 16

Today is the not-so-sweet sixteenth anniversary of the last major earthquake to rattle Puget Sound.

Nisqually Earthquake
Road damage at Sunset Lake, Tumwater, from the 2001 Nisqually Earthquake. Photo: Steven Kramer/University of Washington.

A magnitude 6.8 earthquake struck near Anderson Island at 10:54 a.m. Feb. 28, 2001. Known as the Nisqually Earthquake, the temblor shook the Pacific Northwest, with shaking being felt around Puget Sound, in Vancouver, B.C., Portland, Ore., and as far east as Montana. The Nisqually earthquake produced some $2 billion in damages and injured about 400 people.

Damage could have been much worse, according to reports prepared by DNR’s Division of Geology and Earth Resources. This quake stemmed from the Benioff zone, meaning it came from deep underground (more than 32 miles underground.) The depth of the epicenter meant much of its force was buffered by layers of earth.

On the plus side, the Nisqually quake was responsible for a new set of preparedness measures and research into Washington’s tectonics.

Boosted efforts to map, research faults

In the last 15 years, the number of seismic monitors has more than tripled across the northwest ; GPS units have been deployed for faster earthquake detection; mapping efforts have been boosted by the use of lidar, which has led to the detection of new faults in the Puget Sound area.

Earthquake damage risk
Levels of probable earthquake damage in Washington and Oregon are shown in red, orange and yellow. Image: USGS.

DNR has used much of that research to produce the Washington State Seismic Hazards Catalog, which shows estimates of damage from future quakes of differing magnitude on our state’s many faults. We’ve also worked to document damages from Washington’s historic temblors.

DNR worked with the Washington Emergency Management Division and federal agencies to publish estimates of the potential losses from a magnitude 7.2 earthquake on the Nisqually fault zone. The fault runs beneath Pierce and Thurston counties but 15 other counties would feel this impact, including King County, which would suffer significant damage along with Pierce and Thurston counties.

Working to further knowledge

DNR is working to secure funding and partnerships to further map earthquake and tsunami risks so communities will have the information they need to mitigate potential damages in advance.

Recep teaching kids about earthquakes
DNR geologist Recep Cakir shows a class of Aberdeen preschoolers how geophones work. Photo: Deirdre Clarke/DNR

DNR hazards seismologists have also worked on projects to determine how earthquake waves move through soils around schools so buildings can be strengthened to better withstand future quakes.

When an earthquake happens, there will not be time to Google what you are supposed to do (Drop! Cover! Hold On!). After the earthquake, the internet might not work at all.

For now, you can turn to DNR’s Emergency Preparedness page to find out what you can do in advance of the next big one.

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