Subduction-zone earthquakes aren't the only ones...
The Pacific Northwest is host to more than the anticipated megathrust earthquake that will happen off the Cascadia coast in the future. That earthquake will be due to the stress building between the Juan de Fuca and North American plates as the oceanic Juan de Fuca plate dives deep beneath the Pacific Northwest. However, there are also deep earthquakes within the subducting plate, and shallow earthquakes in the overlying continental crust. This is because of additional forces acting on the region besides subduction-zone processes.
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The Pacific Northwest is host to three kinds of tectonic earthquakes :
Subduction zones show that there are 3 distinct areas of movement in the overlying plate:
This UNAVCO animation compares Japan's subduction zone at the location of the 2011 earthquake with a mirror-image subduction zone in the Pacific Northwest. There are many similarities.
The Pacific Northwest boasts an active volcanic arc (Cascades), a nearby ocean ridge (between Pacific & Juan de Fuca Plates), the world’s youngest flood basalt province (Columbia River Basalt), a hot-spot chain of eastward-younging volcanoes (Yellowstone), Basin-Range extension, and more. This animation simplifies several complex tectonic interaction.
The Pacific Northwest is host to three kinds of earthquakes revealed in this Flash rollover. Subduction zone great earthquakes, shallow crustal quakes, and earthquakes within the subducting plate.
Scroll over the bathymetric relief map to learn about the geographic provinces of the Pacific Northwest.
Learn about the volcanoes of the Pacific Northwest Cascade Range mountains by scrolling over individual volcanoes on this interactive map.
Learn how the Pacific Northwest tectonic setting and megathrust earthquake of January 1700 is similar to the catastrophic earthquake in Japan in 2011 by touching icons on this interactive map.
This rollover compares the an earthquake of 1700 in the Pacific Northwest with the 2004 Sumatra earthquake and tsunami. The tectonic settings are similar.