Alaska—Regional Tectonics and Earthquakes

www.iris.edu/earthquake for more animations. 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 Chumach-St. Elias Ranges and in the Denali Range. See also the M9.2 1964 Great Alaska Earthquake: https://www.youtube.com/watch?http://... Written & directed by Robert F. Butler, University of Portland Animation & graphics by Jenda Johnson, Earth Sciences Animated Narrated by Katryn Wiese, City College of San Francisco Consultants: 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. Funded by the National Science Foundation