Pacific Northwest Megatsunami

Here's an almost-gleeful, Lucifer's Hammer-esque fictionalized narrative of what kind of quake is likely to be caused when the Cascadia Subduction Zone next slips.

Totally Psyched for the Full-Rip Nine

"When that earthquake hits, it's going to shake for a long time," says Corcoran. "Three to five minutes or more. You're going to feel lucky to survive. Then guess what. You rode out the quake? Congratulations. Now you have 15 minutes to get above 50 feet of elevation. Fifteen minutes. [...]"

This startling evidence made seismologists sit up and take notice. Clearly, the Cascadia subduction zone had ruptured in a megaquake in 1700, down-dropping the Northwest coast several feet in elevation and unleashing a killer tsunami.

Of course, the magic number could be 500 years, or (gulp) 244. For the past decade, Chris Goldfinger has been pulling samples from landslide zones off the Oregon coast. By interpreting the cross-sections, he found a record of 19 full-rip nines in the past 10,000 years -- a rate of about one every 500 years. He also discovered 22 CSZ quakes measuring 8.0 to 8.5. That means the CSZ has caused 41 major quakes in the past 10,000 years, or one every 244 years.

So what we have now is a 740-mile section of the world's most seismically active zone, the Ring of Fire, that has been building up elastic strain for 311 years. The North American plate, by some estimates, is now springloaded to leap more than 57 feet west and drop three to six feet in elevation at the coast.

Previously, previously, previously.

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8 Responses:

  1. Brian B says:

    And here I thought I was just about the only one who read Lucifer's Hammer.

    • cthulhu says:

      It was something of a bestseller IIRC. And for double-SF-nerd-cred, name the book that Niven and Pournelle were working on at the time that they put on hold to explore TEOTWAWKI in Lucifer's Hammer (hint - it also involves impacts from space).

  2. DFB says:

    "PITY POOR CASSANDRA, blessed by Apollo with the power of prophecy, cursed with the fate of ­disbelief. She tells the people what’s coming. She suffers their laughter, absorbs their scorn. Then she watches her prediction come true. Yeah, you told us so, they’ll say as they bury the dead. Congratulations, jerk."

    I bet Al Gore has that on his fridge.

  3. 205guy says:

    Maybe the mega-thrust earthquakes also triggered the mega-floods:

    I wonder what happens when a mega-tsunami meets a mega-flood?

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