Where Is The Cascadia Subduction Zone & Why Is Everyone Terrified Of It? What To Know About The Next Big Quake

In a nice bit of doomsday news, rumor has it that a giant earthquake is poised to do some intense damage to California, but we're not taking about San Andreas here. So where is the Cascadia Subduction Zone that everyone is freaking out about? While it's no secret that California is prone to earthquakes, a recent article in The New Yorker by Kathryn Schultz has people sleeping in doorways and terrified. Although earthquakes can hit all over the States, the good news is that only people in northern California need to worry about the impending doom of the Cascadia.

The Cascadia Subduction Zone lies 700 miles off the coast of the Pacific Northwest, stretching from Cape Mendocino, California, all the way up to Vancouver Island, Canada. According to Schultz, the fault wasn't even discovered until 45 years ago, but it has the ability to do some serious damage. It lies just a bit north of its far more famous friend, the San Andreas Fault. But while Californians are way more likely to know the name of San Andreas, its quakes typically tap out at an 8.2 on the Richter scale. Scientists are estimating Cascadia can pack a 9-point punch.

If I were living in the northwest, I'd start making some of my safety precautions now. Or I'd move. Either works.

According to Schultz and her scientists, if the Cascadia were to rupture, it could hit big cities like Portland and Seattle as well as Washington State towns of Tacoma and Olympia. One expert quoted in the piece states that everything west of the Interstate 5 highway would be "toast." That includes 40,000 square miles and 7 million people.

Schultz cites FEMA estimates that 13,000 would die, while 27,000 others would be injured, compared to the 3,000 who died in the 1906 San Francisco quake. The earthquake would be the worst natural disaster in North American history, and the effects of the quake and ensuing tsunami would reach across the states and hit as far as Japan.

The truly terrifying aspect of the article, however, is that Schultz claims the likelihood of a Cascadia earthquake in the next 50 years is one in three, while the odds of the earthquake registering at a nine or higher are one in 10. The largest earthquake ever recorded (so far) was a 9.5 quake in Chile in 1960. The United States takes the record for second largest, after the 1964 Great Alaskan Earthquake, which measured at a 9.2 and created dozens of tsunamis, some higher than 220 feet. That was a result of a subduction zone rupturing.

Through in-depth historical research, scientists have been able to put together evidence of the last time the Cascadia ruptured. Estimates say it was 1700 or 1701, and it resulted in a 9.0-magnitude earthquake. Using this and other historical evidence as proof, scientists have deduced that the average cycle between Cascadia ruptures is about 243 years. It has now been 315 years since the last known quake.

The good news is there is one silver lining to what would otherwise be a disaster film in the making. According to Vox, scientists are actually pretty bad at predicting when the next subduction earthquake will come, because they aren't at all consistent. So that's a relief. Kind of.