FIGURE 3.14 Alaska seismic hazard map showing peak ground acceleration with a 10 percent chance of exceedance in 50 years. SOURCE: U.S. Geological Survey, <>.

chatka to the Gulf of Alaska, and it accommodates most of the convergence between the Pacific and North American plates, which ranges from 6.3 meters per century near the Kenai Peninsula to 8.6 meters per century in the western Aleutian Islands. The largest historic earthquake in the United States (M 9.2) was generated in 1964; its ground shaking and liquefaction caused spectacular damage to Anchorage (Box 2.3). The fault plane responsible for this huge event was equivalent to the area of New York State moving an average of about 10 meters. The megathrust was also the source of great earthquakes in 1957 (M 9.1) and 1965 (M 8.7). Elsewhere in Alaska, major strike-slip faults, including the Denali and Fairweather faults, traverse the interior of Alaska and pose a substantial danger to Juneau. The Denali fault is about 1000 kilometers long and has a slip rate of 0.2 to 1.0 meter per century, but has not ruptured in the past few centuries. Earthquakes in the crust and subducted slab pose a significant hazard to Anchorage and Fairbanks.


The Hawaiian Islands were formed by the passage of the Pacific Plate over a mantle hot spot. This hot spot persists today, its eruptive centers on

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