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Geology of the PNW

Mount Saint Helens (8,366'), the Toutle River, and scars from the 1980 eruption from Spirit Lake Hwy (WA-504), Skamania County

Cascadia Subduction Zone

Portland, as seen from Pittock Mansion, Clackamas County, OR, is the 2nd largest city built on the Cascadia Subduction Zone. Seattle is the largest.

The fundamental structural geologic process that has shaped and continues to shape the landscape of the Pacific Northwest today is the subduction of the Juan de Fuca Plate under the North American Plate. This zone of convergence is known as the "Cascadia Subduction Zone".

 

Keep reading to learn all about the Cascadia Subduction Zone (CSZ) and how it shapes Washington and the Pacific Northwest (PNW), from California to British Columbia.

JUMP TO DIFFERENT PNW GEOLOGY SECTIONS HERE:

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Basic Geologic Principles

Major Geologic Structures

Earthquakes

Volcanoes

Key Terms

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