In his 2007 New York Times bestseller, The Black Swan, Nassim Nicholas Taleb highlights the extreme impacts that rare outlier events can have on our society. These events, known as Black Swans, are highly unpredictable and fly in the face of our tendency to base future expectations on our past experience. To illustrate this concept, Taleb uses the example of a Thanksgiving Turkey. The Turkey lives a plush life on a nice farm and is fed well everyday. Each day he gets a little fatter, and a little happier. After a few hundred days of this, the Turkey is pretty confident that all life has in store for him is more food and relaxation. After a few hundred more days, he is certain that there is no end to this life of luxury. All of his life experience leads him to believe that this trajectory should continue on into the future unchanged. And then, when he is just fat enough, on a cold November day, just before Thanksgiving.... well, you know the rest.
Lucky for us, the large earthquake that we WILL experience in the future, is not a Black Swan. While we cannot predict the exact day or year that it will happen, we KNOW that it WILL HAPPEN. For many people living in the region, earthquakes are part of their living memory. Many remember where they were during the 2001 Nisqually quake, and those that have been here longer remember the 1965 quake. Whether you have experienced a PNW earthquake first hand or not, we all have the benefit of decades of work by geologists to better understand our seismic risk. We know when earthquakes have occurred over the last 10,000 years, and can even assign some probabilities to when our next quake could be. There is an 86% chance that we have a 6.8 or greater earthquake in the next 50 years, and a 15-25% chance that we have a 9.0 or greater. Armed with this information, we can all take steps now to be prepared. We don't have to be that turkey. Happy Thanksgiving!
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