Puget Sound faults about 1100 years ago (AD 900—930) an earthquake of magnitude 7+ uplifted Restoration Point and Alki Point, dropped West Point (the three white triangles in the Seattle Basin on the map), caused rockslides in the Olympics, landslides into Lake Washington, and a tsunami on Puget Sound. It extends as far east as (and probably terminates at) the Rattlesnake Mountain Fault Zone (RMFZ; the southern extension of the SWIF) near Fall City. This seems geologically reasonable, as both the SWIF and RMFZ appear to be the contact between Tertiary Crescent Formation basement of Puget Sound on the west and the older
Puget Sound region Ferries, connects the larger islands to the Washington mainland, as well as both sides of the sound, allowing cars and people to move about the greater Puget Sound region. North Pacific Oak Woodland is one of the principal plant associations of the Puget Trough, where many of the soils are well drained mesic. Counties of the Puget Sound region: In addition, the San Juan Islands (all of San Juan County plus a few islands belonging to Whatcom County) are often considered part of the greater Puget Sound area. Prominent islands: Urban centers: Satellite cities: Other principal cities: Military bases: Puget