As someone stated, this shook in an area not common for quakes. Right in the middle of all the wildfires, in the north central part of the state. The Grand Coulee Dam is also in the area. It's not a huge damn. But it's known as Washington State's Hoover.

4.3 earthquake hits north central Wash. wildfire zone
[link to www.kirotv.com]

Pacific Northwest Seismic Network
[link to pnsn.org]