Is the Planet in a Period of "Megaquakes," or Just a String of Bad Luck?

By Valerie Ross | April 18, 2011 3:22 pm

earthquakeA house decimated by the 2010 earthquake in Chile.

What’s the News: Enormous earthquakes are rare; there have been only seven quakes with a magnitude 8.8 or above since the start of the 20th century. Of those seven quakes, three of them have happened in the past seven years: off the coasts of Indonesia in 2004, Chile in 2010, and Japan last month. Some researchers think this earthquake cluster marks the start of a period of megaquakes, while others believe that the earthquake cluster is simply a statistical fluke, with these unusually massive quakes just happening to occur within a short amount of time, according to recent analyses (PDF) of Earth’s earthquake history presented at the Seismological Society of America’s annual meeting last week.

Some Scientists Say:

  • In a 2005 paper, researchers Charles Bufe and David Perkins from the US Geological Survey identified a cluster of large earthquakes about 50 years ago: three earthquakes with magnitudes of at least 9.0 in Russia, Chile, and Alaska between 1952 and 1964. The random probability of this earthquake cluster—that is, the likelihood the three quakes occurred within that timeframe just by chance—was 4%, they found. From 1950 to 1965, the researchers observed, there were a total of seven earthquakes with a magnitude greater than 8.5—a string of events with a random probability of 0.2%.
  • Building on that analysis, the researchers recently examined earthquake data up through the Indonesian earthquake in 2004. The likelihood of the last half-century’s earthquake distribution being random—with lots of strong quakes from 1952 to 1964, a period of relative calm, then seismic activity ramping up again in 2004—was 2%, they found.
  • Using their analysis, they estimated that the chances of a 9.0 or greater earthquake in the next ten years at 63%, as opposed to the 24% chance if massive quakes happen at random.

On the Other Hand:

  • Another study turned up no evidence that earthquake clusters were anything but chance. Another USGS seismologist, Andrew Michael, mined the seismic record for patterns, using a variety of magnitude thresholds and time scales to run multiple analyses. “I’ve run a large number of tests and can’t find any reason to reject the idea that clustering is random,” he told Nature News.

What’s the Context:

  • These analyses aren’t looking at aftershocks, which have long been known to follow a major earthquake, but at separate seismic events.
  • A recent study found that big earthquakes may trigger more quakes nearby, but don’t seem to up the odds that a large earthquake will happen in a distant part of the globe.
  • It’s not clear why massive quakes would cluster, if in fact they do. It could be that a monster earthquake reverberates through the planet, impacting how tectonic plates move. “Maybe on the very large scale we have a weakening of these very long fault zones that are on the verge of failure,” Bufe told ScienceNews.

References:

  • Charles G. Bufe and David M. Perkins. “The 2011 Tohoku earthquake: resumption of temporal clustering of Earth’s megaquakes.” Seismological Society of America meeting, Memphis, April 14, 2011.
  • Charles G. Bufe and David M. Perkins. “Evidence for a Global Seismic-Moment Release Sequence,” Bulletin of the Seismological Society of America, June 2005. DOI: 10.1785/0120040110
  • Andrew J. Michael. “The recent rate of great earthquakes: global clustering or random variability?” Seismological Society of America meeting, Memphis, April 14, 2011.
CATEGORIZED UNDER: Environment
  • Joseph Weiss

    The mantle is in constant flux as proven with Killeaua (sp?) in Hawaii, therefore there is a natural tendency for earthquakes to develop on the edge of the tetonic plates. If the plates dont move forces will build up under pressure to force movement. This is what we are seeing in Chile, Indonesia and Japan.

  • http://DiscoverMagazine Templar 7

    Mr. Weiss has it right on the money.

    Just factor in all of the oil the world is pulling out from underneath us…simple physics says to me that when you pull something out from underneath,(oil), then whatever is on top must be subject to gravity and fall down/inward(landslides, tetonic plate movement, etc.).

  • John Lerch

    3 megaquakes in a decade corresponds to 2% chance. Hmm 2% = 1/50. So every 500 years we get 3 megaquakes in a decade. Given they seem to be averaging 1 a decade or 2 that sounds about right. IOW 2% being an accident and no evidence of correlation sounds like they’re saying the same thing.

  • MJ

    It might be little too soon to be jumping on the “It’s a Pattern” bandwagon. Though if high magnitude earthquakes are able to set off other 9 pointers, that would produce a pattern.

  • s

    uh…Temp. oil is located ABOVE the fault lines where plates meet.

    the two are unrelated.

    Better go back to your “simple physics” class.

    MJ – agreed. a little too soon to be seeing “patterns”. If only global warming cultists would take a page of proper scientific methodology.

  • Addison

    Well we’re crossing the plane of the galaxy. It could very well be that the planet itself is being subjected to torquing forces as a result of this. The Chinese some years ago correlated the gravitational pull of the moon with the occurrence of some earthquakes. A little twist here, a little twist there, and what do you know? The seam along two plates gives.

    Of course, the fact that all these major earthquakes have occurred along the Pacific Rim might also mean there is something going on with only the Pacific Rim. In which case, California/Oregon/Washington are sitting ducks.

  • Matt B.

    Time to let go of astrology, Addison. The Chinese were wrong (if in fact they made that claim, as you say): http://blogs.discovermagazine.com/badastronomy/2011/03/11/no-the-supermoon-didnt-cause-the-japanese-earthquake/
    As for the galactic plane BS, the orbit of the sun around the center of the galaxy takes 200 million years, and there would have to be a large change in the magnitude of gravity, not angle. Your concept of time scales needs revision if you think that will cause large variation on the order of 100 years.

  • http://WINEBREWINGINFO.COM Julian Blanc

    Some times its a pain in the ass to read what blog owners wrote but this site is really user friendly!

  • http://Alétezésfantasztikumablog.hu viktoria

    Kedveseim. A tudósok nagyon tévednek, vagy elhallgatnak dolgokat. Sajnos a Földünk haldoklik. Persze a bolygó agonizálása elég sokáig tart épp úgy mint a természetes leépülése az életnek ami szintén egyfajta. Ez az agonizáló, inkább átalakuló folyamat 1991 08.01 kezdődött és eltarthat kb. még 420000 évig. az élet szempontjából sajnos sokkal hamarabb válik majd alkalmatlanná a felszíne.

    De addig egyre több lesz a földrengés, új és alvó tűzhányók kitörése, az óceánok tengerek vizének fokozatos melegedése –benne az élővilág pusztulása = az emberiség éhínség, amit még az időjárás drasztikus változása is rontani fog= növekedni fog az elsivatagosodás= az éhínség.

    A globális felmelegedés matt a levegőbe kerül az északi jegek alatti metán, a sarkok felolvadásával veszélybe kerül a tiszta ivóvíz készlet.

    S mind ez egy természetes folyamat egy bolygó életében, csak épp az élővilág pusztulhat bele!

    Mitől történhet ez meg? Mert a bolygónk eredetileg hideg volt teljes anyagában fagyott, és élete folyamán csak fokozatosan melegedett át a belsejétől kifelé haladva. S korunkra csak egy tojáshéjnak megfelelő héj az amin az élet létezhet kb 6-10-15km széles csak az óceánok alatt ennél csak kevéssel több a száraz kéreg alatt –síkságok alatt- A hegyeket ostobaság figyelembe venni mert azok csupán félgyűrődések amelyek cm-ről cm-re mindig növekednek észrevétlenül.

    A Földünk egyszer olyan lesz mint egy forró platni aminek a felszínét metán, és CO fogja beborítani a kérge pedig mint érett leejtett görögdinnye fog számtalan helyen repedni, mint amilyen jelenleg is csak épp nem látjuk még eltakarják a óceánok és tengerek . Honnan tudom? keress meg a blog cimen A létezés fantasztikuma. üdv viktória

  • http://Alétezésfantasztikumablog.hu viktoria

    Mitől történhet ez meg? Mert a bolygónk eredetileg hideg volt teljes anyagában fagyott, és élete folyamán csak fokozatosan melegedett át a belsejétől kifelé haladva. S korunkra csak egy tojáshéjnak megfelelő héj az amin az élet létezhet kb 6-10-15km széles csak az óceánok alatt ennél csak kevéssel több a száraz kéreg alatt –síkságok alatt- A hegyeket ostobaság figyelembe venni mert azok csupán félgyűrődések amelyek cm-ről cm-re mindig növekednek észrevétlenül.

    A Földünk egyszer olyan lesz mint egy forró platni aminek a felszínét metán, és CO fogja beborítani a kérge pedig mint érett leejtett görögdinnye fog számtalan helyen repedni, mint amilyen jelenleg is csak épp nem látjuk még eltakarják a óceánok és tengerek . Honnan tudom? keress meg a blog cimen A létezés fantasztikuma. üdv viktória

  • http://Alétezésfantasztikumablog.hu viktoria

    Bocsánat, de számomra ismeretlenül működik ez a web rendszer. Remélem sikerült leírni az üzenetem Nektek jobb a web fordító is kérlek fordítsátok le fontos. Köszönöm üdvözlettel Magyarországról.

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