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. https://www.iris.edu/hq/inclass/animation/alaska_tectonics_and_earthquakes | EarthScope Consortium