Magnitude 4.2 quake strikes near Grand Coulee Dam in Washington
Grand Coulee Dam (Shutterstock

A magnitude 4.2 earthquake struck near Grand Coulee Dam, the largest U.S. hydropower facility, in northeastern Washington state on Tuesday, prompting an immediate inspection of the facility but leaving no visible damage, a spokeswoman said.

Operations of the dam, which supplies electricity to 11 Western states, were not disrupted by the tremor 25 miles (40 km) north of the facility, according to the spokeswoman, Lynne Brougher of the U.S. Bureau of Reclamation, the agency that runs the dam.