It's an earthquake fault that makes San Andreas look tiny...very tiny (weather.gov)

In case you haven't heard about the Cascadia Sub Fault off the Pacific Coast, you will now.  For several years, scientists and geologists have been studying this massive fault, which is roughly 70-100 miles off the coasts of CA, OR and Washington state.

It's formal name is the Cascadia Subduction Zone. Basically, it makes the San Andreas Fault look like a paper cut. It's been there for hundreds of years, but only in the last few have officials noticed increasing seismic activity on and around it. Enough so that the government has put together evacuation and other emergency plans.

The next time you're at Seaside, OR or other places, look around for the Tsunami Emergency signs and evacuation routes. They didn't used to be there.

Estimates vary, but depending upon the size of the earthquake on this 1,000 mile long fault, and it's location, the Washington coast, Puget Sound and even Seattle could be hit with ten foot waves.

The Department of Natural Resources has released a series of videos of computer simulations of a 9.0 Richter Scale quake, and what it would do. The video we included was of the general Washington state coastline.

The last known activity, or believed activity of the fault, was in the 1700's, based upon geological evidence. Officials say it's likely due to for more, could happen in a year, or ten, or 50.  They just keep watching it, and watching.