The U.S. Geological Survey reports that a 4.6 magnitude earthquake has rattled the Three Lakes area of Washington state.
That was followed minutes later by a 3.5 magnitude aftershock near the city of Monroe, some 30 miles (48 kilometers) northeast of Seattle.
The initial temblor was recorded at 2:51 a.m. local time on Friday.
There were no immediate reports of damage or injuries.
Meanwhile, aftershocks of last week's big earthquakes are still rumbling beneath the California desert, but seismologists say the probability of large quakes in that area continues to decline.
At approximately 6:11 a.m. Pacific Time on Friday morning, a magnitude 4.9 earthquake shook the Los Angeles area, centered in Ridgecrest, California, according to the USGS.