Ross Reynolds speaks with Bonnie Henderson about her new book "The Next Tsunami: Living on a Restless Coast."
Just off the coast of Washington and Oregon is a fault line with potential to unleash an earthquake larger than the deadly magnitude 9 Japan quake in 2011 that triggered a tsunami.
Henderson tells the story about how geologists learned of the Cascadia Subduction Zone and how public officials have tried to adopt safety measures.
Spoiler alert: when you hear a siren, walk and keep walking.
