Earthquake centered under Anderson Island touched off increased attention in earthquake science and emergency preparedness.
It’s been a decade and a half since Washington felt its last damaging earthquake.
At 10:54 a.m. on Feb. 28, 2001 a magnitude 6.8 earthquake struck near Anderson Island. 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.
But 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.
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.
DNR hazards seismologists have also worked on projects to determine how earthquake waves move through soils around schools so they 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.