On March 11 of 2011, Japan and the world were given a wake-up call1 when a powerful natural disaster nearly destroyed the country. The 9.0-magnitude2 earthquake that struck northeastern Japan also led to a massive3 tsunami with over 40-meter waves. Even worse, the tsunami caused a series of nuclear4 accidents at the Fukushima Nuclear Power Station. All this resulted in more than 15,000 deaths, nearly 13,000 people being injured or missing, and an estimated US$300 billion in damages.

　　While Japan is recovering from the disaster, it is only a matter of time before Seattle, Washington suffers the same fate. This city is located just east of the Cascadia fault, which stretches nearly 1,000 kilometers from Vancouver Island, Canada to northern California. Scientists fear that a megathrust earthquake5, like the one that hit Japan, is likely to destroy the entire area. Megathrusts are the world's largest earthquakes and occur when one tectonic plate is forced under another. This month, National Geographic Channel works with experts to discover more about this huge threat on "Disaster Earth."