A doomsday tsunami is likely to strike the US in the near future, but scientists say it’s better if it hits sooner rather than later.

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The CSZ is a nearly 700-mile-long fault line off the west coast of North America where one tectonic plate, the Juan de Fuca Plate slides beneath another, the North American Plate.

It stretches from northern Vancouver Island in Canada to the southern half of the US West Coast, running along the coasts of Washington, Oregon, and California.

If an earthquake between 8.0 and 9.0 in magnitude struck today, scientists warn that a 100-foot mega tsunami would wipe out most of the West Coast, as the coastline would drop by almost eight feet instantaneously.

The Federal Emergency Management Agency (FEMA) estimated that there would be 5,800 deaths from a CSZ earthquake alone and another 8,000 due to the mega tsunami it would unleash.

The international team, led by researchers at Virginia Tech, added that these dire predictions will only get worse as more time passes because of rising sea levels.

Professor Tina Dura, the lead author of the study, said: ‘This is going to be a very catastrophic event for the US, for sure. The tsunami is going to come in, and it’s going to be devastating.’

A magnitude 9 earthquake in the northwest US could destroy half a million homes and cause the deaths of countless people. Pictured: Aftermath of the 9.0 quake that struck Japan in 2011

The Cascadia zone, which sits under Washington, Oregon, and northern California, is said to be ‘overdue’ for another major earthquake. The last one struck in 1700

By 2100, climate change is predicted to raise sea levels by as much as two feet. If the Cascadia Subduction Zone doesn’t suffer another mega earthquake until then, it will likely amplify the devastation and flooding beyond the damage expected in 2025. 

The 2022 emergency report from FEMA projected that there would be more than 100,000 people injured and over 618,000 buildings damaged or destroyed during the next major CSZ earthquake.

That damage would include more than 2,000 schools and 100 critical facilities along the West Coast, costing the country more than $134 billion.

The new study published in the Proceedings of the National Academy of Sciences also predicted that the West Coast would be reshaped for centuries.

The earthquake and mega tsunami would radically expand 100-year floodplains in Washington, Oregon, and California by as much as 115 square miles.

Floodplains are areas expected to suffer historic flooding at least once every 100 years. If those regions suddenly expanded by more than 100 miles, more homes, roads, and local infrastructure would fall into dangerous flood zones.

However, in the worst-case scenarios where subsidence (sinking of the ground) is at its highest, the researchers estimated that their flood zone predictions could more than double.

‘After the tsunami comes and eventually recedes, the land is going to persist at lower levels,’ Dura told BBC Science Focus. ‘That floodplain footprint is going to be altered for decades or even centuries.’

The Cascadia Subduction Zone extends along a nearly 700-mile strip of the Pacific Ocean off the coast of southern Canada, Washington, Oregon, and northern California. If it ruptured, it could cause a magnitude-9 earthquake throughout the region. The darker areas mark the areas that would receive the most damage, extending inland, where the devastation would be more moderate

The Cascadia Subduction Zone is becoming a major area of concern now because of the growing amount of time that’s passed since its last major seismic event.

The last major earthquake struck on January 26, 1700. Historians and scientists estimate that it was a magnitude 9.0 earthquake which unleashed a mega tsunami that destroyed the village of Pachena Bay in British Columbia.

Records of the event show that waves up to 100 feet high struck just 30 minutes after the quake, leaving no survivors.

The CSZ marks the boundary where the Juan de Fuca Plate is sliding (subducting) under the North American Plate.

However, this movement isn’t smooth. The plates periodically get stuck together at the fault line which builds up stress over many years.

That stress continues to accumulate until it finally reaches a breaking point and releases massive amounts of seismic waves that we feel as a devastating earthquake.

Since this fault line sits in the Pacific, it also unfortunately disrupts the ocean, sending out gigantic waves from the epicenter.

Scientists have estimated that the CSZ builds up into a major earthquake every 400 to 600 years, meaning it’s already been 325 years since the last cataclysmic event.

‘You can imagine, during the next earthquake, when the land drops down, you’re going to suddenly have to contend with multiple centuries of equivalent sea level rise in minutes,’ Dura warned.