The earthquake had an estimated magnitude of 6.6 , 6.5 and 6.7 . At 10 – 20 seconds the duration of strong ground motion was relatively short . The earthquake 's focal mechanism indicates that it resulted from normal faulting within the Juan de Fuca slab . There were no recorded aftershocks , similar to observations from the 1949 Olympia and 2001 Nisqually earthquakes and a characteristic of such intraslab events
1949 Olympia
1949 Olympia earthquake
1965 Puget Sound earthquake