Our dextral faults mean, among other things, that the west coast of California is moving toward Alaska at the rate of about an inch and a half per year. At that rate, it will take some time for San Francisco to arrive offshore of the Gulf of Alaska, but it will happen. As the mass of the Pacific plate is sliding sideways to the northwest along the Denali and related faults, it abruptly runs into a stone wall, as it were, along the Aleutian Islands, the Aleutian Range, and the Alaska Range west of Cook Inlet. In the parlance of geophysicists, this creates a subduction zone characterized by underthrusting. Although much of this goes on slowly and unnoticed, when strain accumulates to the point that its release produces a big jump, it attracts everyone's attention.
Anchorage overlies an underthrust segment of the Pacific plate.
The 1964 earthquake provided graphic evidence that sudden movement along the underlying thrust fault can go a long way toward reshaping our scenery. Very large strike-slip earthquakes have occurred in southeast Alaska. One of the more spectacular of these was the Lituya Bay earthquake of 1958, which toppled an entire mountainside into the bay, creating a splash that cleared timber and topsoil from a mountain ridge 1500 feet above sea level. Although they cannot be seen at the surface, Fairbanks lies very nearly on top of a local system of strike-slip faults extending from the southeast to the northwest. These probably arise from stresses in the Alaska Range and the Denali fault to the south being transmitted into the Interior.