Most dangerous U.S. earthquake zone
Hidden off the US Western shore, beneath the Pacific Ocean, is the Cascadia Subduction Zone. This fault is capable of generating earthquakes larger than magnitude 8 that can be felt hundreds of miles away, and a recent study has pinpointed the most dangerous segment along its 700-mile-long stretch.
The results will help scientists assess earthquake and tsunami risk for this region, including one particularly vulnerable state: Washington.
"This has been a subduction zone that's been under-studied with the kinds of tools that we have available now," geophysicist Suzanne Carbotte, a Bruce Heezen Lamont research professor at Columbia University, told Business Insider.
Armed with state-of-the-art technology that can probe deep beneath the ocean floor and create images, Carbotte and her team produced the first comprehensive survey of Cascadia's complex, below-ground composition. They published their work today in the peer-reviewed journal Science Advances.
The researchers discovered that Cascadia is broken up into at least four segments, which had been suggested by previous studies but never confirmed, Carbotte said.
The picture "before our study was a smooth surface with no obvious relationship to this segmentation," Carbotte said. "But that smooth surface was based on very, very sparse data. And in places, no data."
This new picture provides a much more accurate view of Cascadia's complexity, and of the risk it poses to the US West Coast.
| by Anonymous | reply 8 | June 12, 2024 10:33 PM
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The Cascadia subduction zone is ripe for rupturing (usually does so about every 300-500 years and it's been more than than 300 now since the last one. However, the most vulnerable places are not the largest cities, which are well away from the coast. Long Beach would be total inundated by the tsunami and anyone on it at the time of an earthquake would certainly die. There is no high spot to run to, no place to drive to quickly enough to outrun a tsunami. Parts of Puget Sound could conceivably be hit with very high tsunami waves -possibly 100 feet or higher. (Places like Cultus Bay on Whidbey Island). A 9 point earthquake off shore would probably translate to at least a 6 point earthquake in the large cities of Washington, like Seattle and Tacoma, and there would be a lot of serious infrastructure damage, although Seattle has been trying to retrofit old buildings, bridges, etc to withstand stronger earthquakes. Apparently these types of megathrust earthquakes can lead to a shaking for 5 minutes, so with each additional amount of time, the damage would multiply. There is no doubt that it would cause billions of dollars of property damage, and infrastructure for fleeing the cities could be impassable. (Hundreds of bridges over creeks to get up and over the Cascade range using interstate 90 or highway 2 into eastern Washington might be destroyed, for example).
| by Anonymous | reply 1 | June 11, 2024 8:23 AM
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Basically, everything west of Interstate 5 will be laid to waste.
There was an EXCELLENT article about the Cascadia Subduction Zone (and how it was discovered) in The New Yorker, back in 2015. Having lived in L.A. my entire life, I was well-acquainted with the San Andreas Fault (and that impending "Big One"), as well as the threat posed by some of the "lesser" fault-systems in the greater L.A. area. That article was the first time I'd EVER heard of the Cascadia Subduction Zone...and my jaw was on the floor by the end.
| by Anonymous | reply 2 | June 12, 2024 9:18 PM
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My uncle was living in Alaska in 1964 when they had the 9.3 earthquake. He said it seemed to go on forever.
| by Anonymous | reply 3 | June 12, 2024 9:24 PM
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[quote] Basically, everything west of Interstate 5 will be laid to waste.
You seem barely capable of concealing your joy over the prospect. But calm down. This isn’t Sumatra and the Cascadia fault isn’t the Great Sumatran.
| by Anonymous | reply 4 | June 12, 2024 9:28 PM
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New Madrid Fault Zone will be pretty catastrophic too. Many people live in the Zone now.
| by Anonymous | reply 5 | June 12, 2024 9:29 PM
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[quote]You seem barely capable of concealing your joy over the prospect
JOY??? Not sure how that was your take-away from my post, jackass R4.
There was no JOY expressed my post...just surprise (and dread) at the discovery of the of the Cascadia subduction-zone faults & evidence of past catastrophic earthquakes.
| by Anonymous | reply 6 | June 12, 2024 10:05 PM
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And it will be blamed on Biden by the MAGA.
| by Anonymous | reply 7 | June 12, 2024 10:14 PM
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I'm sure insurance companies are rejoicing at the newly justified premium rate increases. Even though it's prohibitively expensive to buy earthquake insurance and your house was structurally unaffected by an earthquake, the threat of fires, looting, etc. will give them plenty of justification.
| by Anonymous | reply 8 | June 12, 2024 10:33 PM
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