According to this story on KGW, scientists are now theorizing that the entire Cascadia Subduction Zone could shake simultaneously (rather than bits of it quaking at separate times), bringing the Richter Scale estimates for “The Big One” up from 8.0 to 9.0. Remember, the Richter Scale is a base-10 logarithmic scale in which each increment is exponentially larger than the one before. So a 9 is ten times bigger than an 8. Or, put another way:
8.0 – 8.9 = Serious damage for hundred of miles
9.0 – 9.9 = Devastating damage for thousands of miles
In any case, it’s all the more reason to get prepared.
(photo courtesy of www.usgs.gov)