Where have all the earthquakes gone? Oregon.
WHATS IN THIS BLOG:
• Earthquakes in Oregon?
• The big one is coming.
• It will be the worst natural disaster in the history of North America.
I’VE WRITTEN ABOUT EARTHQUAKES IN OKLAHOMA, caused mainly by the oil-and-gas industry (see HERE and HERE). The numbers reached their peak in 2015-2016 and have been falling since then due partly to regulations by the Oklahoma Corporation Commission.
I’ve also written about Kansas earthquakes (see HERE), which were caused by the same oil-and-gas practices that spilled over the border from Oklahoma. Seismic activity dropped from 1,967 earthquakes in mid-2015 to 668 earthquakes at end of 2016 (both were 5-month recording periods). The number of quakes dropped to one-third of what it was in a period of 18 months, and this was partly due to new State regulations.
EARTHQUAKES IN OREGON? If I’d said Hawaii, nobody would’ve been surprised. The explosions of volcanic magma and hundreds of earthquakes associated with them have been well-documented on TV.
But Oregon? Yesterday morning, 29 July, at 11 am Central Time, there were 5 earthquakes recorded within an hour of each other. I have an earthquake app, which whistles at me whenever an earthquake greater than magnitude 3 occurs in the USA. All of these were off the coast of Oregon. The biggest magnitude was 5.3. Anything greater than magnitude 5 can cause structural damage, but of course there are no structures in the ocean. Could it be a warning though?
The answer is yes.
THE BIG ONE IS COMING.
A great fault, called the CSZ fault, is 620 miles long and lies 50 miles offshore Oregon. The CSZ is overdue for a mega-earthquake, meaning magnitude 8-9 or greater.
The last one was in 1700, and down through history mega-earthquakes have occurred every 244 years on average. Since it’s been 318 years since the last big one, Oregon is overdue. Geologists have predicted the next big one will occur within the next 50 years, with high probability. An enormous tsunami will cause a Katrina-like disaster – the hurricane that devastated New Orleans in 2005. The damage there was estimated to be $70 billion.
Everywhere along the Oregon coast are tsunami warnings, like the sign in the picture. How do you escape a tsunami if you feel a really big earthquake, like magnitude 9? You have just 15 minutes to get to higher ground, meaning 100 feet higher than the beach. The signs recommend running, but Gray Nomads like me do not run anymore.
Instead, I’d have to blaze out of the house and leap into the car. I’d have to do that in less than 5 minutes, to beat all the other folks trying to get away. Within 10 minutes it’d be a local traffic jam on the road to higher ground.
As reported HERE, a mega-quake is the kind of massive offshore earthquake that triggered the tsunami that killed 28,050 people in Japan on March 11, 2011 (the Fukushima earthquake). Geologists also call the Northwest coast of North America—from Vancouver Island down to Northern California—one of the likeliest next victims.
DRAIN THE OCEANS. This National Geographic TV series, on Monday nites in my area, reveals what the ocean bottom would look like if the seawater were drained away. I was fascinated with this concept. One episode in the 2018 series was called Deadly Pacific. Off Oregon, National Geographic showed what the CSZ fault would look like if the seawater were drained away.
The CSZ fault is where two tectonic plates are sliding past each other. In this Cascadian subduction zone (CSZ), the ocean plate called Juan de Fuca slides downward and pushes the North American plate upward, building underwater hills and mountains. For large periods of time the sliding along the fault surface separating the two plates gets stuck. But when it gets unstuck and slips, tremendous energy can be released in the form of an earthquake. A small slip distance means an earthquake of magnitude 3-5, which happened yesterday morning. A large slip causes the Big One – magnitude 8 or 9.
A PULITZER PRIZE. An article called The Really Big One, won a Pulitzer Prize for its author, Kathryn Schulz. It was published in 2015 in the New Yorker, July 20 issue. Click HERE to read the article.
Here is a chilling excerpt from this article:
By the time the shaking has ceased and the tsunami has receded, the region will be unrecognizable. Kenneth Murphy, who directs FEMA’s Region X, the division responsible for Oregon, Washington, Idaho, and Alaska, says, “Our operating assumption is that everything west of Interstate 5 will be toast.”
In the Pacific Northwest, the area of impact will cover some hundred and forty thousand square miles, including Seattle, Tacoma, Portland, Eugene, Salem (the capital city of Oregon), Olympia (the capital of Washington), and some seven million people. Roughly three thousand people died in San Francisco’s 1906 earthquake. Almost two thousand died in Hurricane Katrina. Almost three hundred died in Hurricane Sandy.
FEMA projects that nearly thirteen thousand people will die in the Cascadia earthquake and tsunami. Another twenty-seven thousand will be injured, and the agency expects that it will need to provide shelter for a million displaced people, and food and water for another two and a half million.
In fact, the science is robust, and one of the chief scientists behind it is Chris Goldfinger. Thanks to work done by him and his colleagues, we now know that the odds of the big Cascadia earthquake happening in the next fifty years are roughly one in three. The odds of the very big one are roughly one in ten.
THE WORST NATURAL DISASTER IN THE HISTORY OF NORTH AMERICA. It’s not the San Andreas fault-line in California that will be the cause of the next Big One, but more likely the CSZ fault offshore Oregon. According to Schulz’ article, when the next full-margin rupture happens, the coastlines of Oregon and Washington will suffer the worst natural disaster in the history of North America.
Later this year I’m planning a trip to the Oregon Coast, but you can bet I’ll be planning an escape route as soon as I get there… just in case!
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PS: I write blogs about Science and Energy, Inspiration and Hope, and Health and Hiking.