The Daily Need

U.S. is due for a sizable quake, but not because of Japan’s

Image adapted from U.S. Geological Survey seismic hazard map released in 2008.

Yes, a quake of at least 6.7 magnitude will likely hit the United States soon, experts say, but the disaster in Japan is not an indication that said quake will hit any sooner.

The West Coast is home to two geologic features that make it ripe for major temblors: the San Andreas fault in California and the Cascadia subduction zone in the Pacific Northwest. Both have lain silent for more than a century. Is the U.S. overdue?

Many experts think the answer is “possibly, yes.” The U.S. Geological Survey says there is a 99 percent probability that California, in particular, will experience a  6.7 or higher magnitude quake in the next 25 to 30 years. The probability of a quake of 7.5 or higher in that time frame is 46 percent.

Despite speculation to the contrary, however, the recent disasters in Japan, Chile, New Zealand and Haiti haven’t done anything to increase the odds.

During the week and a half since Japan was shaken by the 9.0-magnitude quake, many academics and science journalists have appeared on television discussing the Ring of Fire, a collection of tectonic plates under the Pacific that includes, among others, the Pacific plate, the Nazca plate (off the western coast of South America) and the Filipino plate (off the eastern coast of the Philippines). The question is frequently posed: Does increased activity in one part of the “Ring” have an affect on the other parts?

Simon Winchester, an author and earthquake expert, suggested on MSNBC last week that since earthquakes have recently wreaked havoc in three corners of the Pacific – an 8.8 in Chile last year, a 6.3 in New Zealand in February and now a 9.0 in Japan — the fourth corner — that is, America’s West Coast — will likely soon be seeing the compensating tectonic movement.

According to Steven Wojtal, an earthquake expert and professor of geology at Oberlin College who has studied fault lines – in particular, the San Andreas fault — for years, things aren’t quite that simple.

First, the Chilean earthquake was not caused by the same plate as the earthquakes in Japan and New Zealand. In Chile, the quake was caused by a shift in the Nazca plate, while in Japan and New Zealand quakes were caused by the Pacific plate.

Courtesy U.S. Geological Survey

And, though North America’s West Coast is also on the Pacific plate, the U.S. and Canada are so far from Japan and New Zealand (and on such a different part of the plate) that, on this side of the Pacific, we are unlikely to feel any tectonic backlash from the tremors abroad, Wojtal explained.

But “predicting earthquakes will never be like predicting the weather,” he said.

And, if Japan’s disaster isn’t a geologic warning to California, the century-long silence on the San Andreas fault is. The last earthquake along the fault, in April 1906, is remembered as one of the worst natural disasters in American history. The quake and resulting fires took the lives of some 3,000 people, the largest loss of life from a natural disaster in California’s history. In 2008, the USGS predicted that California would see a large earthquake within the next three decades. And many fear the state is not sufficiently prepared.

The Cascadia subduction zone, off the coast of Oregon and Washington, is less worrisome. The subduction zone causes extremely intense earthquakes, but much more irregularly — on average, every 500 to 600 years. The last was, according to a USGS professional paper, on January 26, 1700 — about 311 years ago. Europeans had not yet settled the Pacific Northwest, and there are no Native America records of the quake, but, by studying tree rings and Japanese accounts of the resultant tsunami, researchers have estimated the quake was between an 8.7 and a 9.2 – one of the worst in our continent’s (relatively) recent history.

For now, most experts, including Wojtal, recommend that the West Coast should remain wary – specifically, those on the West Coast must ensure that their building codes are up to snuff. When it comes to the toll on human life, “natural disasters are only part of the story,” said Wojtal. It’s not the earthquakes that kill people, he pointed out, it’s collapsing buildings. The difference between Haiti — where a 6.3-magnitude quake reduced much of the country to rubble — and Japan — where most buildings withstood a 9.0-magnitude earthquake (if only to be leveled by the tsunami) — was preparedness.

 
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Comments

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    and stumbled on a research in which there is all the software that I needed. justified recently reinstalled the operating system

  • http://pulse.yahoo.com/_FCPYFNSTFYTD3ILTDKXEAATAAY Captian America

    Hey I like those odds. Its more then apparent the we need to build geothermal power plants…. True clean energy for 100% of the country.

  • Anonymous

    Don’t try to scare us with such paltry numbers. Yes, 6.7 is huge to someone in…say…South Dakota, but 6.7 isn’t that large for the west coast.

    We’ve experienced 7.5s , we’ve been waiting on a 9 to hit any minute for over the last 20 or so years.

  • Anonymous

    I figure it is just “our turn” here in CA, it has been awhile and even “skipping” the science of it the law of averages puts us up to bat next. The BIG question is if that would set Mt St Helen off again :/

  • http://www.facebook.com/dmbleighton Dianna Leighton

    “The West Coast is home to two geologic features that make it ripe for major tremblers: the San Andreas fault in California and the Cascadia subduction zone in the Pacific Northwest. Both have lain silent for more than a century. Is the U.S. overdue?”

    Wouldn’t the 1989 Loma Prieta earthquake (6.9) and the 2004 Parkfield earthquake (6.0) factor into this?

  • Maggie Caldwell

    I wondered the same thing.

  • Math is Hard

    “The Cascadia subduction zone, off the coast of Oregon and Washington, is less worrisome. The subduction zone causes extremely intense earthquakes, but much more irregularly — on average, every 500 to 600 years. The last was, according to a USGS professional paper, on January 26, 1700 — about 411 years ago.”

    2011-1700=311

  • Anonymous

    Thanks for the correction, MiH. You are right, and it has been corrected.

  • Vert_chin

    Ummm, no mention of the giant hot-pink blob in the midwest. What’s the time frame on that one?

  • GirlFriday

    That is the New Madrid fault line, which hasn’t had a big quake in 200 years. I grew up in the area hearing about the big quake of 1811 and having an earthquake disaster kit in our hall closet. Interesting read on Wiki.

  • SLS in CA

    Temblors (not tremblors) is the correct term when referring to earthquakes, even if we tremble or become tremblors ourselves when they jostle us or worse.

  • SF_Reader

    Paltry? A 6.9 took down bridges and freeways in California.

  • Kiahhendricks22

    Omg I’m sick to my stomach..I live right by the oregon coast… would it be safe or right to move my family from this area??? I mean this is really scary and serious! What so u think? Should I move? Is it likely to effect willamette valley??

  • Phil E. Drifter

    We made Mother Earth angry with our pollution and rampant RAEP of her natural resources, she’s trying to shake us off! EVERYBODY PANIC!

    Wait… I know what to do! We can all clasp our hands in prayer and WASTE OUR TIME PRAYING to an entity that DOES NOT EXIST.

    Aliens? Definitely.

    Supernatural deities that create us for their own amusement just to test us after giving us free will and then punishing us for using it? NEV4R!

    Stop being stupid and evolve. Do something grand with your life so that you’ll be remembered.

  • Darryll Kahn

    Have you ever experienced an 6.7+Mw event? Where were you in 1989 when the Loma Prieta quake ravaged the Bay area from Monterey Bay to the Market District of S.F.? It broke two bridges — collapsing one completely!

  • read carefully

    ‘Due for an earthquake!?!?’ I’m disappointed that they would conform to such a horrible cognitive bias. Show me the scientific connection! How much time has passed since the last earthquake does not determine when the next one will occur.
    Also, keep in mind predictions are being made for decades from now!
    They have also not been able to answer the very important question of whether movement in one part of the ring of fire activates other parts.

  • http://ixthye.blogspot.com/ EriK

    The earthquakes don’t exist solely to ‘test’ us. The ‘whole of creation is groaning and travailing together in birth pangs’ due to the Curse. The world isn’t perfect. It used to be. We didn’t want it. It shall be again. But you’ll only get to experience it if you want it bad enough to seek after God.

    In an evolutionary universe, why would an earthquake be a bad thing? It’s just a natural force of the earth, driving evolution. And people dying? They’re just chemical reactions becoming disorganized by a natural process of geological evolution. You think this CREATED the human race. Why would you think this is a bad thing, to the extent that you would consider that this disproves God? You have no basis to claim that it is evil in your worldview. Please consider this.

  • Steviefirepants

    What?

  • Ben Dover

    I believe that was the Hayward fault, which is of course associated with the San Andreas. To make the claim the San Andreas has been silent for over a century is absurd and ignorant… Small quakes are ABUNDANT every week. Look at USGSs real-time seismology tracker.

  • http://pulse.yahoo.com/_6QQHKWU4VEAJGTNE3RJWGZUQ4E Tiffany

    It isn’t just buildings that kill people during earthquakes. There is an atomic power plant sitting on the beach between San Diego and L.A.

  • http://pulse.yahoo.com/_6QQHKWU4VEAJGTNE3RJWGZUQ4E Tiffany

    It isn’t just buildings that kill people during earthquakes. There is an atomic power plant sitting on the beach between San Diego and L.A.