The Big One is Coming to Cascadia Fault

Mega-Tsunami Threat Looms as Cascadia Fault Builds Toward 9.0 Quake, Experts Warn
Dashel Pierson
Fri, April 3, 2026

It’s not a matter of if, but when.

The big one, so to speak, is coming. And according to recent study from the Proceedings of the National Academy of Sciences, there’s a 15% chance of a rupture in the Cascadia Subduction Zone in the next 50 years, and a 29% chance by the year 2100.

Located off the Pacific Northwest, the Cascadia Subduction Zone last erupted in 1700. And according to the experts, it’s overdue for another shake. When it does, coastal communities could be devastated, with waves from the potential 9.0 quake reaching unfathomable heights. We're talking about a wave that will wipe cities off the map.

“In the Pacific Northwest, a slow-motion collision of tectonic plates known as the Cascadia Subduction Zone has been building tension for over 320 years,” says meteorologist Maiya May. “And when that tension is released, the resulting earthquake is likely to be as large as a magnitude 9.0. That would be 45-times more powerful than California’s most destructive quake in 1906. And the consequences defy imagination.”

Although the Cascadia Subduction Zone lies off the coast, the destruction on land from such a massive earthquake is expected to be devastating. And that’s before the resulting tsunami from the tremor is triggered and sent hurdling across the Pacific.

The West Coast, Japan, Hawaii – all within the path of impact.

“Subduction zone earthquakes often cause sudden movement and changes on the ocean floor, triggering tsunamis large enough to completely wipe coastal communities off the map. Remember the Fukushima power plant disaster? In 2011, Japan was hit by a magnitude 9.0 earthquake, similar to what we’re anticipating here.”

So, just how big will the resulting tsunami from the Cascadia Subduction Zone be? Hard to say. Some estimates range from 100-to-1,000 feet. But the thing about tsunamis is, it’s not always about the size. It’s often more like a massive, unrelenting tidal surge.

“Situational awareness really comes into play if you’re on the coast,” the video continues. “You’re not only facing the earthquake, which will destroy buildings and bridges, but a giant tsunami will follow right behind. High ground could save your life.”

This story was originally published by Surfer on Apr 3, 2026, where it first appeared in the News section. Add Surfer as a Preferred Source by clicking here.
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1,000-Foot Tall ‘Mega-Tsunami’ Could Hit West Coast, Experts Warn
Dashel Pierson
Tue, July 29, 2025


The last time the Cascadia Subduction Zone shifted was in 1700, triggering an earthquake registering between 8.7 to 9.2 on the Richter scale and resulting in a tsunami that struck the west coast and Japan.

The Big One.

For most residents of the world, particularly in California, the threat of a gigantic earthquake is always looming – one that would devastate communities, upend life as we know it, cause billions in damage, and take with it untold multitudes of casualties.

Scary stuff. But with some earthquakes, there’s also the aftermath, aka tsunamis. And scientists have been looking at one specific fault line off the west coast of North America, with regards to its imminent shifting, and the resulting, potential “mega-tsunami.”

A recent study from the Proceedings of the National Academy of Sciences looked at the Cascadia Subduction Zone, an offshore fault line that stretches from North Vancouver Island in Canada to Cape Mendocino in California. The team primarily looked at the flood risks, coupled with sea level rise, in relation to the Cascadia Subduction Zone.

According to the study, there’s a 15% chance of a rupture in the Cascadia Subduction Zone in the next 50 years, and a 29% chance by the year 2100.

“Today, and more so in 2100 as background sea levels rise, the immediate effect of earthquake-driven subsidence will be a delay in response and recovery from the earthquake due to compromised assets. Long-term effects could render many coastal communities uninhabitable,” said lead author of the study, Tina Dura.

The team also looked at past “mega-tsunamis” to better evaluate the potential carnage in the Pacific Northwest. For example, by examining marine sediments, experts were able to confirm a 1,312-foot tsunami that struck the Hawaiian island of Lanai 105,000 years ago. That one was different, however, as it was created by a volcanic landslide.

As for the Cascadia Subduction Zone, the last time that tectonic plate shifted was in 1700. It triggered an earthquake registering somewhere between 8.7 to 9.2 on the Richter scale. And the resulting tsunami struck both the west coast and across the Pacific in Japan.

Now, researchers warn that the same zone is due for another shake.

“Given the global prevalence of subduction zones, these insights hold relevance beyond Cascadia, informing hazard assessments and mitigation strategies for tectonically active regions worldwide,” Dura added.

1,000-Foot Tall ‘Mega-Tsunami’ Could Hit West Coast, Experts Warn first appeared on Surfer on Jul 28, 2025.