Tectonics & earthquakes of Alaska—More than just plate boundaries


Related Animations
    Megathrust Earthquakes
    1964 Great Alaska Earthquake

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Regional Alaskan Tectonics

Alaskan tectonics are dominated by Pacific-North American plate interaction. The megathrust boundary between the plates results in both the 4,000-km-long Aleutian Trench and in the arc of active volcanoes that lie subparallel to the trench. This animation discusses the range of tectonic activity from megathrust earthquakes to accretion of geologic terranes. Along the trench, the rate of convergence ranges from 5 cm/year on the east to 7.8 cm/year on the west. The angle of subduction also changes from shallow in the east to steep in the west. In the Gulf of Alaska region, the subduction of the Yakutat plateau complicates the area, and is responsible for mountain building in the Chugach-St. Elias Ranges and the Alaska Range.

 mp4 (18.2 MB)


Written & directed by Robert F. Butler, University of Portland
Animation & graphics by Jenda Johnson, geologist
Narrated by Katryn Wiese, City College of San Francisco
    Robert C. Witter, USGS Alaska Science Center
    Peter J. Haeussler, USGS Alaska Science Center
    Michael West, Alaska Earthquake Center
Maps from Google Earth. Epicenters from UAF Alaska Earthquake Center.
Photos from UAF Geophysical Institute, Alaska Department of Natural Resources, & US Geological Survey.

Please send feedback to Jenda Johnson.