That Big WA Offshore Earthquake Could Happen Much Sooner Than Thought

If you haven't heard of the Cascadia Subduction Zone, you will. It's that huge fault that lies between 50-60 miles off the Pacific Coast, ranging from California up Oregon and Washington's coasts. And experts now say it could be due to move big time within the next 50 years.

The fault has come into focus a lot more in the last decade due to much more research and advanced equipment for tracking activity. Basically, it's a huge crack that makes the San Andreas fault in CA look like a paper slit. It ranges several hundred miles up the coast.

The Cascadia could cause devastation not seen in the U.S. if it registers a significant quake, and experts say it last had a major movement sometimes in the early 1700's.

Officials now say hundreds of samples and monitor results, including core samples from various locations on and offshore show the fault moves about every 430 years, and is likely to move again in the next 50 or less. What type of quake they are referring to is if the entire zone moves, like it did in 1700 and sent shock waves that reached Japan with some size.

They've also learned weak or movement points are especially prominent in line with Seattle, Portland and other coastal cities.

While estimates are just that, estimates, officials say a full-scale quake would produce tremors and a tsunami that could kill as many as 10,000, destroy as many as 85,000 buildings on the coast and inland, and cause over $30 billion in damages.

They say the probability of such a quake is now between 15-20% likely in that 50 year time frame. Officials have already begun to prepare plans of what to do if it appears eminent or actually occurs, and they continue to monitor it frequently.