Witness an 8.9 Mega quake then watch as a 30 foot high tsunami Destroys many cites of Japan. Its only a matter of time before a devastating earthquake hits a major American city and wipes it off the map. Scientists now believe that day could be sooner than we thought. And its not Los Angeles or San Francisco thats in danger. But Seattle, Washington, the crown jewel of a region called Cascadia in Americas Pacific Northwest. Scientists fear Cascadia could suffer a catastrophe of global proportions:a megathrust earthquake. It is the largest earthquake the planet can create.