A series of earthquakes struck off the coast of the Pacific Northwest, scientists said late Monday. The quakes, ranging up to magnitude 5.9, did not trigger any tsunami threat, they said.

The first earthquake, at magnitude 5.8, reportedly hit before midnight Sunday, followed by four other quakes. On Monday evening, sixth and seventh earthquakes of magnitude 3.9 and 4.2, respectively -- the weakest of the cluster -- hit the region. The quakes were reportedly shallow, about 6-mile deep, and centered in an area about 300 miles west of Coos Bay, Oregon.

"It's a well-known place for earthquakes," Julie Dutton, U.S. Geological Survey’s (USGS) geophysicist said, according to the Associated Press (AP). "They're frequent throughout the year."

USGS seismologist Seth Moran reportedly said: “These earthquakes are happening in a totally different part of the system and aren’t really relevant in a physical way.”

According to the AP, which cited a 2008 USGS report, the zone where the latest earthquakes hit had produced about 70 quakes of magnitude 5 or greater in the last 28 years, and in 2008, scientists detected hundreds of smaller quakes in the region.