The area regularly experiences large earthquakes as it is situated on the southern end the Cascadia subduction zone and near the San Andreas Fault , which interface around the Mendocino Triple Junction . On January 9 , 2010 , a 6.5 magnitude earthquake occurred about off shore from Eureka . After two seconds , it became a violent " jumper " , making objects fly ; the mostly vertical shocks from the ground led to broken windows in shops , overturned shelving in homes and stores , and damage to architectural detail on a number of historic buildings . Local hospitals treated mostly minor related injuries , and electrical power was out over a large area . Numerous natural gas leaks occurred , but no fires resulted . This was the largest recent earthquake since the April 25 – 26 , 1992 sequence . It was followed on February 4 , 2010 , by a magnitude 5.9 earthquake which struck about northwest of the community of Petrolia and nearly west of Eureka . The shaking was felt within a radius , as far north as southern Oregon and as far south as Sonoma County . The largest recorded in the area was the 7.2 event on November 8 , 1980 . The larger earthquakes can pose a tsunami threat to coastal areas
6.5 magnitude earthquake
2010 Eureka earthquake
Eureka, California