Oregon has been building westward over the past 150 million years by a process known as subduction. As an oceanic plate dives beneath the continent, it adds material to the edge by faulting and volcanic activity. The current Cascadia Subduction Zone is just the most recent subduction zone – its landscape features and geologic activity profoundly influence Oregon’s history, climate, safety – and beauty!
In this window learn how landscapes affect climate through the formation of the Cascade Range rain shadow. You can also learn how the Beauty and the Beast of the Cascadia Subduction Zone creates the beautiful parallel mountain ranges (Coast Range and Cascade Range) but creates beastly natural hazards such as volcanic eruptions, earthquakes, and tsunamis (see Windows 7, 13, and 14).
Photo: Robert J. Lillie
This diagram shows the plate tectonic forces beneath the Earth in a subduction zone, and how they shape the landscape around us.
Digging Deeper: For more information, visit these websites.
Oregon Department of Geology and Mineral Industries (DOGAMI): Coastal Hazards
http://www.oregongeology.com/sub/earthquakes/earthquakehome.htm
DOGAMI: Introduction to Oregon Geology:
http://www.oregongeology.com/sub/learnmore/learnmore.htm
Digging Deeper: For more information, give this sample of books a read:
Geology of Oregon, 5th Edition by Elizabeth L. Orr and William N. Orr (2000, Kendall/Hunt [http://www.kendallhunt.com/]) Professors at the University of Oregon, the Orr’s have been writing about Oregon’s geology for decades.
In Search of Ancient Oregon by Ellen Morris Bishop (2003, Timber Press [http://www.timberpress.com/]) Take a photographic journey through time and see Oregon’s ancient places.
