Along the west coast of the Unites States and Canada, earthquakes are common due to the fact that here the Pacific Plate encounters the North American Continental Plate.

The scenic beauty of the Pacific Northwest landscape reflects active geologic processes. An offshore plate tectonic boundary, the Cascadia Subduction Zone, closely parallels the coastline of Washington and Oregon.

In the Pacific Northwest one finds several vulcanic mountains, many of them sleeping, but sometimes they awake like Mount St. Helens, which erupted violently on May 18, 1980. Furthermore each year several thousand Pacific Northwest earthquakes are recorded. Many are located near the urban areas of Seattle and Portland, where damaging earthquakes occur every 30 years or so. In addition, huge earthquakes (including several larger than magnitude 7) occur directly on the Cascadia Subduction Zone margin every few hundred years. Small daily earthquakes, plus occasional felt tremors, remind Pacific Northwest residents of earthquake hazards.

Use the following links for relevant information on earthquakes:

• Most recent notable earthquake
  
• List of most recent notable earthquakes
  
• Catalog of recent earthquakes
  
• Pacific Northwest Earthquake Information
  
• Pacific Northwest Seismograph Network