Oregon on Shaky Ground: Earthquakes and Landslides

Earthquakes and landslides can shake up Oregon — and Oregonians — at any time. The largest earthquakes in the world occur where one tectonic plate dives — or “subducts” — under another, and we’re sitting right on top of the Cascadia Subduction Zone (See

Window 2). Such devastating earthquakes occur about every 200 to 600 years in the Pacific Northwest. Our last major earthquake occurred in the year 1700 AD and generated a tsunami that struck Japan. Oregonians are at the forefront of studying and preparing for not only these mega-disasters, but also more moderate earthquakes and landslides that threaten our lives and livelihoods.

In this window, learn about the different types of earthquakes that occur in Oregon, including the 1993 Scotts Mills (“Spring Break Quake”) that closed the Capitol building, forcing extensive repairs. You can also see the effects of landslides, annually Oregon’s most expensive and dangerous natural hazard.

Digging Deeper: For more information, visit these websites:

Oregon Earthquakes (DOGAMI)

http://www.oregongeology.com/sub/earthquakes/EQs.htm

A homeowner’s guide to landslides (Compiled by Scott Burns and others at Portland State University for FEMA)

http://www.oregongeology.com/sub/Landslide/homeowners-landslide-guide.pdf

Landslide Hazards in Oregon:

http://www.oregongeology.com/sub/Landslide/Landslidehome.htm

Oregon Earthquake Information (US Geological Survey)

http://earthquake.usgs.gov/regional/states/?region=Oregon

View earthquakes from around the world, including those that happened today!

http://earthquake.usgs.gov/

http://www.iris.edu/seismon/

The Pacific Northwest Seismic Network monitors volcano and earthquake activity: http://www.pnsn.org/welcome.html

See a real time seismograph for many areas in the Pacific Northwest:

http://www.pnsn.org/WEBICORDER/PNSN/welcome.html

Oregon’s Offshore Earthquakes:

http://www.pmel.noaa.gov/vents/oregon-quakes.html

Make sure you’re prepared! Put together a disaster preparedness kit:

http://www.oregon.gov/DOGAMI/emergencykit.shtml

Historic Earthquakes in Oregon:

http://earthquake.usgs.gov/regional/states/oregon/history.php

http://earthquake.usgs.gov/regional/states/historical_state.php#oregon

http://www.ess.washington.edu/SEIS/PNSN/HIST_CAT/

http://www.oregongeology.com/sub/publications/OG/OGv57n06.pdf

The National Science Foundation EarthScope Program (National Office at Oregon State University) has seismometers and GPS instruments around the United States that record signals from earthquakes and volcanic regions: http://www.earthscope.org

Put a seismometer in your school through Oregon Shakes:

http://www.oregonshakes.com/

Digging Deeper: For more information, give this sample of books a read:

Living with Earthquakes in the Pacific Northwest, 2nd Edition by Robert S. Yeats (2004, OSU Press [http://oregonstate.edu/dept/press/])

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.