Probability

Let’s face it, when there is an 80% chance of snow, grocery stores turn into zoos! Humans are really good at preparing for emergencies when the risk is high. We see the same thing during wildfire, tornado and hurricane seasons.

But there is no season for earthquakes. In some areas, they happen often enough that being prepared for one is common among residents. In locations like the Pacific Northwest, we experience few. It makes taking the risk seriously, much harder.

The way we discuss the risk can sometimes impact how motivated we are to prepare as well. Looking at the percentages below (all based on a 50-year outlook), it can feel like the level of risk depends on who you ask. (Click the buttons to read the articles)

OSU.JPG OregonLive.JPG New Yorker.JPGEOS.JPG

Discussing risk on a 50-year outlook makes most people shrug it off. More, which percentage is correct?? Where there are multiple narratives, it gets hard to internalize the risk. One of the main reasons I created this page was to help explain where the probability numbers come from and why there are multiple answers given.

So, which percentage from above is correct? Well, it depends. Each percentage is correct… because each percentage uses different criteria. Frustrating, right? The answers are complex, because earthquakes are. For example, are we taking about the whole fault rupturing or just a segment of it? Which segment? Is the log-normal or normal probability model being cited? Both are considered equally valid.

If you are interested in seeing how the calculations work for the probabilities, click the CALCULATIONS page. It can be helpful to know where the numbers come from. Percentages can help us better understand risk, but hopefully our home page illustrates why the probability models may not be the best narrative for talking about risk here.