Vancouver is completely submerged. Seattle and Portland are decimated by volcanoes, landslides and tsunamis. An earthquake might not destroy the west coast - but a megaquake just might. Californians have been ready for "The Big One" for decades, but a tremor much farther north on the San Andreas Fault may spring to life. And, it could be ten times bigger. Most earthquakes last for a minute, but a "megathrust" earthquake can last for five - powerful enough to trigger a cascade of smaller earthquakes and even reignite extinct volcanoes. Join leading geologists and discover why America's northwest may be in imminent danger. It just might make you tremble.