FAQs about the Natural History of the Inside Passage

3. How active are the tectonic plates in Southeast Alaska? What is the risk of earthquakes?

Earthquake risk is high in much of the southern half of Alaska. The Pacific plate is sliding northwestward past southeastern Alaska and then dives beneath the North American plate in southern Alaska, the Alaska Peninsula, and the Aleutian Islands. Most earthquakes are produced where these two plates come into contact and slide past each other. The Queen Charlotte-Fairweather fault presents the greatest earthquake hazard to Southeast Alaska.

On June 28, 2004, a magnitude 6.8 earthquake occurred on the Queen Charlotte-Fairweather fault, 70 miles southwest of Craig in the Pacific Ocean. It was felt strongly in Southeast Alaska and northern British Columbia. No injuries and only minor damage have been reported. This earthquake was the largest to occur in the Queen Charlotte-Fairweather fault since the magnitude 6.3 earthquake on February 17, 2001. The largest recorded earthquake that had previously ruptured this section of the fault was the magnitude 8.1 earthquake on August 22, 1949.