The last time the Juan de Fuca oceanic plate jolted under the North American plate, unleashing a 9.0 earthquake, was in 1700. With the event scheduled to happen once every 500 years or so, we are due for another any day now. Although it’s not clear what will happen when this mega quake does hit, researchers at the University of Washington recently presented 50 possible scenarios of how the event might unfold.
Earthquakes are typically measured using the Richter scale, named after the geologist who invented it in the 1930s. The scale is numbered from 0-10, although no magnitude 10 earthquake has ever been observed, making a 9.0 one of the most powerful quakes in recorded history. The predicted earthquake, dubbed the “Really Big One,” will take place where the Juan de Fuca and North American plates meet along Cascadia subduction zone, just north of the San Andreas fault line. The earthquake would affect those living in coastal Washington, Oregon, British Columbia and Northern California, and a 2015 New Yorker article predicted the quake and its subsequent tsunami could affect 7 million people.
There’s no saying exactly how this quake will strike exactly. Geologists typically use past earthquakes to predict future ones, but no recording devices were around to take data on the 1700 Cascadia earthquake. The researchers at the University of Washington hope to address this problem.
The team presented both best- and worst-case scenarios of a potential 9.0 earthquake on the Cascadia subduction zone at the Geological Society of America’s annual meeting on October 24. Their 50 simulations use different factor combinations, such as where the epicenter may be, how far inland the earthquake would travel, and where along the fault the shaking would be the strongest. They were run on supercomputers at the Pacific Northwest National Laboratory and the University of Texas, Austin. Although other reports have looked into possible scenarios of this predicted earthquake, this is the most in-depth scenario prediction to date, The Independent reported.
“With just a few simulations you didn’t know if you were seeing a best-case, a worst-case or an average scenario,” explained lead study researcher Erin Wirth in a recent statement. “This project has really allowed us to be more confident in saying that we’re seeing the full range of possibilities.”
Some of the report’s predictions include that the quake will be less severe in Seattle if the epicenter were beneath the tip of northwest Washington, although the sediment grounds in Seattle would cause it to shake more than areas on hard rocky mountaintops. Shaking in Seattle could last as long as 100 seconds. The simulations also predict that coastal areas would be hit the hardest.
Although all science suggests that the Really Big One will occur and that this will likely be sooner than later, there really isn’t a need for panic. These simulations are just one part of a huge collaborative project known as the M9 Project. Created at the University of Washington, this project aims to develop ways to better predict an earthquake as soon as possible to give people ample time to seek safety. Oral history of Native American tribes living on the Pacific West Coast in 1700 describe entire tribes being swept away with post-earthquake tsunamis, but 500 years of geological and technological advancements point to the next quake being far less devastating.