Cascadia? The place where they expect a devastating earthquake, and it is not San Francisco

A monumental geological fault threatens the lives of millions of people in a place you may never have heard of.

The first reaction is to think of San Francisco or Los Angeles, California and its many predictions of destruction by the San Andreas Fault.

But that's about Cascadia. The fault that affects it is also in the Pacific Ocean. According to a report by CNN, "its enormous size and potential power astonishes earthquake experts, who could cause the worst natural disaster in North America's history (if it collapsed completely)".

This earthquake is located at the bottom of the Pacific Ocean, where the seabed meets the North American tectonic plate. In total, it extends 1126.54 kilometers along the Pacific Northwest, from Vancouver Island, British Columbia to Washington, Oregon, and Cape Mendocino, in the north of California.

In fact, "The Cascadia" has already marked history by causing the largest earthquake of the continental United States on January 26, 1700. It is then that Cascadia unleashed one of the largest earthquakes which caused a tsunami so great that it swept the Pacific and damaged coastal cities of Japan.

Now scientists say the question of when the Cascadia Fault will hit again is an important issue.

This great earthquake could "strike at any time" and there is even a website called Aftershock that allows Oregonians to enter their address to receive a personalized report on seismic risk. If the Cascadia Fault produced a major earthquake, the resulting earthquake and tsunami could kill more than 11,000 people and injure more than 26,000, according to a model from the Federal Emergency Management Agency (FEMA). English).

Cascadia is more scary than San Andrés

Everyone knows Cascadia's cousin in California: the San Andreas Fault. It attracts all the terrifying glamor, even with a film this year: "Earthquake: The San Andreas Fault", in which an apocalypse is dramatized in the western United States.

The truth is that the San Andreas Fault is a light weight compared to that of Cascadia.

That of Cascadia can cause an earthquake many times more powerful … except for a tsunami.

"The Cascadia Fault can cause an earthquake almost 30 times with more energy than that of San Andrés, then generate a tsunami at the same time, which can not be generated by the side-by-side movement of San Andrés. said Chris Goldfinger, professor of geophysics at Oregon State University.

The Cascadia Fault is capable of triggering an earthquake with a magnitude of 9.0 … an impressive demonstration of Mother Nature's strength.

"You'll have three to five minutes of shaking, and if you're used to California earthquakes, these times usually last 15 to 30 seconds, and before you're really sure what's going on, it's finished, "said Goldfinger.

A magnitude 9 will be different.

"In that case, three minutes – and I went to one of the nine in Japan – three minutes is an eternity, it's very, very long," says Goldfinger. "We will lose a lot of bridges, we will lose our roads, the coast will probably be closed by fallen bridges or landslides, or both."

You can also read this now in case you ever get caught in such a disaster: rescue teams would be overwhelmed.

"Because there will be damage on all roads, on different roads and infrastructure, and that it will also be very difficult to move and badess what is happening, how to reach the and provide them with some of the resources they may need, "said Commander Richard Ouellette of the Pacific Region Civil Air Patrol.

Revelations on the lethality of Cascadia

Before the 1980s, the Cascadia Fault was neglected because it did not seem to move or cause earthquakes.

Scientists now know something else.

"The more we know, the less we love it, because it also becomes a great danger," said Goldfinger.

To demonstrate that the Cascadia Fault had already broken, scientists studied the "ghost forests" of the Pacific Northwest.

Under the plants and trees, the earth and the mud, changes in the landscape are recorded. While digging, Brian Atwater, a geologist from the United States Geological Survey, found evidence of one of the largest earthquakes in the world.

"The field test for the tsunami here is the layer of sand that rests on the forest floor where these trees took root," Atwater said.

He discovered that after the earthquake, the coast had been reduced by about 1.5 meters and that a few minutes later, the tsunami had reached a fir forest, bathing it in the forest. water from the ocean. The trees could not survive in the salt water, but many of their hollow and dead trunks still survive today … indicators of the devastation of the Cascadia centuries ago.

By inspecting the rings of the trunks and the remaining roots, the scientists reduced the date on which the Cascadia Fault had broken down … between 1680 and 1720.

With this information, the Japanese earthquake researcher, Kenji Satake, has consulted newspapers and registers of prominent families and temples from the 600s Shogun era. The mission was to find the narrative of a tsunami that had not been accompanied by a storm or an earthquake in Japan.

Scientists were already curious about whether a tsunami could have occurred as a result of an earthquake in North America. After all, the researchers concluded that seismic activity in South America caused tsunamis in Japan in 1586, 1687, 1730, 1751 and 1837.

Several records indicate that an orphan tsunami following earthquakes or a storm in Japan actually crashed on its shores in January 1700.

"You know, the scientific community has strong debates on many details, but not on this fundamental conclusion," said Atwater.

There is no way to predict the next big earthquake

Unfortunately, you can not see the Cascadia Fault in the same way as the San Andreas Fault, which leaves a visible line in some parts of California.

The Cascadia Fault is under water, where the oceanic plate is submerged by the North American plate. The "Cascadia subduction zone" owes its name to the Cascadas mountain range that parallels the fault and the way a plate is subducted or pbaded under another.

There is no way to predict when the Cascadia Fault will offer the next big one, says Goldfinger.

"I wish there was a way, but no, there is none," Goldfinger says. "We can not see ahead and say that we are about to happen or that it should have happened some time ago."

These earthquakes are the price of paradise on the west coast.