A lot has been written about the Cascadia Subduction Zone.  Here are links to some of articles:

• Cascadia Rising is a major exercise that took place in June 2016.  Here’s the Exercise Scenario Document.
• “The Really Big One” is an article by Kathryn Schultz of The New Yorker magazine.  It took the country by storm in the summer of 2015.
• “How to Stay Safe When the Big One Comes” is Schultz’s followup article in The New Yorker.