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Earth Moon Japan Science Technology

The Moon's Gravitational Pull Can Trigger Major Earthquakes, Says Study (nature.com) 130

schwit1 writes: A careful statistical analysis of when major earthquakes occur has suggested they are more likely to be more powerful if they occur around the full and new moons when tidal forces are at their peak. Nature.com reports: "Satoshi Ide, a seismologist at the University of Tokyo, and his colleagues investigated three separate earthquake records covering Japan, California and the entire globe. For the 15 days leading up to each quake, the scientists assigned a number representing the relative tidal stress on that day, with 15 representing the highest. They found that large quakes such as those that hit Chile and Tohoku-Oki occurred near the time of maximum tidal strain -- or during new and full moons when the Sun, Moon and Earth align. For more than 10,000 earthquakes of around magnitude 5.5, the researchers found, an earthquake that began during a time of high tidal stress was more likely to grow to magnitude 8 or above." As these results are based entirely on statistical evidence, not on any direct link between tidal forces and actual quakes, they are quite uncertain and unproven.
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The Moon's Gravitational Pull Can Trigger Major Earthquakes, Says Study

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  • by Anonymous Coward
    "The Moon's Gravitational Pull Can Trigger Major Earthquakes, Says Study".
    No the fucking study does not say that at all, it says their is some correlation between the tidal stress and the size of earthquakes.
    • by DrYak ( 748999 ) on Tuesday September 13, 2016 @06:15AM (#52877547) Homepage

      Yeah, but
      "Study shows statistical correlation that might suggest that tidal stress could be among the dozens of other factors that each contribute slightly in favor of stronger earthquakes", though much more accurate, doesn't have the same "oomph" and thus doesn't manage to sell the same amount of eyeballs to the ad-company paying for this fucking article.
      "The moon will kill with its earthquake power! Cower in terror!! Panic!!! Buy products to feel better!!!!" works so much better...

      • by gtall ( 79522 )

        It is more likely "Ignore those extra quakes in Oklahoma, it is the moon, you see?!?"

        • by Anonymous Coward
          Well, getting people to stop trying to pin Earthquakes on fracking is a good thing, right up there with re-educating creationists. Since the earthquake happens because of tectonic stress, the fracking helps to release that stress early in a much smaller-than-it-would-have-been quake. The anti-oil folks should probably find a different row to hoe.
          • the fracking helps to release that stress early in a much smaller-than-it-would-have-been quake. The anti-oil folks should probably find a different row to hoe.

            Yes, instead of a single huge quake happening several millenia from now, we're much better off having medium-sized quakes destroying houses every week.

        • I see the traditional Slashdot disease of not reading the fucking article before commenting stupidly hasn't cured in the last week.
    • by doccus ( 2020662 )

      Perhaps.. but it's hardly "breaking news" either. In fact it HAS been shown years ago now that the moon can *trigger* earthquakes during full and new moons. Land tides are hardly a newly discovered phenomenom . So a study that says the moon has an impact on the size of quakes is simply another stiudy to bolster evidence of the moons influence. But..... :yawn: When we have that nasty EQ here in the pacific NW maybe I'll look up at the moon..while the tsunami wipes out everything lower than 300 feet... :-(

  • by czert ( 3156611 ) on Tuesday September 13, 2016 @03:26AM (#52877129)
    Well, it's actually the added stress from the Sun's alignment with Earth and Moon that's likely to play the major role here. The Moon itself doesn't do anything special during the full and new moons.
    • That is probably the dumbest comment ever.
      And it even got modded up by even dumber moderators?

      Well, it's actually the added stress from the Sun's alignment with Earth and Moon
      The sun is always there. The sun does not add anything.

      The moon is adding its weight to the pull of the sun, either by _adding_ and pulling in the same direction like the sun if the moon is between earth and sun, or by _pulling opposite_ of the sun when the moon is on the opposite side.

      The Moon itself doesn't do anything special during

  • by The Evil Atheist ( 2484676 ) on Tuesday September 13, 2016 @03:57AM (#52877203) Homepage

    As these results are based entirely on statistical evidence, not on any direct link between tidal forces and actual quakes, they are quite uncertain and unproven.

    Given that the article does not say tidal forces CAUSE quakes, this cushioning is completely unnecessary. They're only noting a suggestion of a link between tidal forces and the magnitude of the quake - not the occurrence/non-occurrence of a quake.

    And something being "based entirely on statistical evidence" does not invalidate or weaken anything. It is the quality of the statistical evidence, not the mere use of statistical evidence, that would invalidate or weaken a claim.

    • To say the truth, this is a very old theory. A guy [wikipedia.org] spent his life searching for connections between tides and earthquakes.
      • *hypothesis

      • Many people have been trying to find correlations between the occurrence of earthquakes and the occurrence of other phenomena which might possibly give predictive ability for earthquakes, and they've been trying (scientifically and less scientifically) for somewhat more than a century.

        No-one has had significant success up to this date - this result barely makes it to significance with a corpus of relevant earthquakes of only a dozen or so. And the (putative) discovery of this weak signal is likely to mean

    • by jheath314 ( 916607 ) on Tuesday September 13, 2016 @06:21AM (#52877569)

      Earthquakes cause full moons!

    • >And something being "based entirely on statistical evidence" does not invalidate or weaken anything. It is the quality of the statistical evidence, not the mere use of statistical evidence, that would invalidate or weaken a claim.

      Well, in this case, that evidence is purely of correlation. Correlation does not imply causation. Now as it happens - they aren't even claiming causation and there is no reason to suspect it. The suggestion is that tidal forces can make quakes worse - and there are conceivable

      • by Alomex ( 148003 ) on Tuesday September 13, 2016 @09:32AM (#52878341) Homepage

        Correlation does not imply causation.

        This has become a /. meme. What is your suggestion here, that there is a third agent responsible both for earthquakes and full/new moons?

        In real life, science correlation is often converted into causation using Occam's razor or logical physical principles. E.g. while there is nothing in theoretical physics forbidding the interpretation that the light about to start shining made you turn the switch, we choose for a variety of other reasons, the interpretation that the causation is the other way around, we turn on the switch, then the light goes on.

        • >What is your suggestion here, that there is a third agent responsible both for earthquakes and full/new moons?

          Fallacy. There isn't only ONE alternative.
          A correlation ONLY proves that things happened to at the same times. Nothing more. Where you have a correlation between X and Y any of the following could be true.
          1) The correlation could be because X causes Y - this is the one everybody assumes
          2) The correlation could *actually* be because Y causes X
          3) The correlation could be because an unknown, Z, ca

          • by Alomex ( 148003 )

            What you say is true in the abstract, though to be accurate 4 is a special case of 3 if you think about it.

            After each experiment, one must consider all five alternatives before reaching a conclusion. However in this specific case the only reasonable conclusions are 1 and 5, which is why bringing up the "correlation does not imply causation" is just a meme.

            A valid comment would have been "wait, how big is the earthquake sample? how large is the increase in intensity?, could it be just random variation?". Th

            • A valid comment would have been "wait, how big is the earthquake sample? how large is the increase in intensity?, could it be just random variation?". There is no way to answer those questions,

              The sample of earthquakes (note : "sample", not "population") showing this effect is of "great earthquakes", not all earthquakes. But when they extend their analysis to M5.5 quakes the correlation disappears. There have been a dozen "great earthquakes" in instrumental history.

              Our catalogues of quakes of M5.5+ are ess

        • a third agent responsible both for earthquakes and full/new moons

          Yes - its agent Gibbs - don't you watch NCIS?

        • This has become a /. meme. What is your suggestion here, that there is a third agent responsible both for earthquakes and full/new moons?

          God? [rawstory.com]

          Sorry, sorry. I'll see myself out... ;-)

      • by dcw3 ( 649211 )

        While the correlation doesn't imply causation, correlation might be helpful in prediction. If events A and B often occur together, and the frequency of that correlation (X), and you know when A happens, couldn't you reasonably say there's an X% chance of B occurring.

    • by jrumney ( 197329 )

      And something being "based entirely on statistical evidence" does not invalidate or weaken anything.

      It depends if you consider correlation to be weaker than causation. Statistical evidence is correlation. You now need to come up with a theory to explain the cause of that correlation, and test the theory to see if it can be proven. With only a correlation, there is still a possibility, however remote, that the relationship you have noticed has appeared in the data purely by chance.

    • I think it would be interesting knowledge when creating models of earthquakes. If you have models of earthquakes that predict the distribution of quakes for all the values of the richter scale. It acts as a power law, a bit like the old sandpile avalanche model. Then what happens if you add a disturbance, does this affect the distribution or not? For instance, intuition might say it decreases the chance of the largest quakes, triggering them early so they are smaller. This would affect the distribution. So

    • Interesting to note that a week from the big Tohoku earthquake in Japan (2011), it was one of the biggest Super Moon of the decade.
    • Given that the article does not say tidal forces CAUSE quakes, this cushioning is completely unnecessary.

      Given that the title under which the article was posted to /. is "The moon's gravitational pull can trigger major earthquakes, says study", the cushioning was not only necessary but inadequate.

  • Is the reverse true? (Score:3, Interesting)

    by bazmail ( 764941 ) on Tuesday September 13, 2016 @04:32AM (#52877301)
    Do moonquakes occur during these periods?
    • by Anonymous Coward

      Only during a full earth or new earth...

    • by quenda ( 644621 )

      Do moonquakes occur during these periods?

      Are you serious? The moon is in gravitational lock, so experiences no tidal stress.
      Have you not noticed that the same side of the moon always faces the earth?

      OK, there is some tidal force from the sun, but the moon is also kind of small, and solid. No molten core, no ocean, no thin crust, no plate tectonics.

      • by Black.Shuck ( 704538 ) on Tuesday September 13, 2016 @06:38AM (#52877623)

        And yet [nasa.gov].

      • by sjbe ( 173966 ) on Tuesday September 13, 2016 @08:42AM (#52878035)

        Are you serious? The moon is in gravitational lock, so experiences no tidal stress.

        Not actually true. Because Earth is not tidal locked to the moon, the rotation of the Earth will cause tidal stresses on the Moon because the Earth is not a uniform body, nor is the moon. Tidal locking does not equal no tidal stresses.

        Have you not noticed that the same side of the moon always faces the earth?

        Again not completely true. See lunar libration [wikipedia.org]. The orbit of the moon is not circular, the Earth itself rotates and their respective axis of rotation are not identical. So we don't always see precisely the same face of the moon. We actually see about 59% of the moon's surface though not all at the same time.

        OK, there is some tidal force from the sun, but the moon is also kind of small, and solid. No molten core, no ocean, no thin crust, no plate tectonics.

        There also are some tidal forces from the Earth on the moon. The effect appears to be quite minor. Moonquakes are apparently a thing and apparently ARE caused at least in part [wikipedia.org] by tidal interactions between the Earth and the Moon.

        • the Earth itself rotates and their respective axis of rotation are not identical.
          Which is completely irrelevant for the question if another object is tidal locked or not.

    • TIL there are moonquakes.

      • To be fair, our knowledge of these things is pretty much in it's infancy. When New Horizons sent us the first close-up pictures of Jupiter recently - the single biggest shock was how varied the land is. Mountains. Valleys. All the signs of a geologically active body - and no known mechanism for what could possibly let this relatively tiny little thing far from the sun's energy be geologically active. What could power it ? Is it still active or did it merely used to be, once, long ago ?
        Mars was considered ge

        • Re: (Score:2, Funny)

          by Anonymous Coward

          "When New Horizons sent us the first close-up pictures of Jupiter recently - the single biggest shock was how varied the land is."

          Actually, the biggest shock would have been that it was Jupiter, not Pluto, like it was supposed to be...

        • All the signs of a geologically active body - and no known mechanism for what could possibly let this relatively tiny little thing far from the sun's energy be geologically active.

          I assume you're talking about Pluto, not Jupiter. I'm not sure I agree that there is "no known mechanism". Charon and is a huge moon, relatively speaking. The two are tidally locked to each other and the barycenter exists outside of Pluto. The tidal forces between them probably don't tell the whole story, but I'd imagine they're at least partially responsible for any geological activity.

    • There's a lot less likeliness of Moonquales happening:

      - The Moon, as mentioned by others is tidally locked with Earth.
      i.e.: It's always the same side facing Earth
      that means that Earth tidal stress is always "pulling" the exact same part.
      thus no change in this "pull" and therefore no directly-earth-caused tides on the moon.

      - The Moon is a huge solid rock, it doesn't move much, whereas the Earth is pieces of solid crust all covering a molten mantle on which they more or less float (the "more of less" part bei

      • - The Moon, as mentioned by others is tidally locked with Earth.
        i.e.: It's always the same side facing Earth that means that Earth tidal stress is always "pulling" the exact same part. thus no change in this "pull" and therefore no directly-earth-caused tides on the moon.

        Incorrect. The Earth is not a uniform sphere and it is not (yet) tide locked to the Moon. The Earth does exert tidal stresses on the Moon because the gravitational pull on the moon is not uniform.

        - The Moon is a huge solid rock, it doesn't move much, whereas the Earth is pieces of solid crust all covering a molten mantle on which they more or less float (the "more of less" part being when they bump into each other, rub against each other, or one dives under another).

        That very malleability of the Earth is a big part of what causes tidal stresses on the Moon. Remember that tidal forces are simply the results of unequal gravity between two bodies. If the bodies aren't uniform the tidal forces by definition cannot be zero. Tidal lock does not mean no tidal stresses. In fact

  • There used to be a geologist on Coast to Coast AM (Art Bell's radio show) who always claimed that there was a relationship between the moon and earthquakes. He predicted the 1989 World Series quake and lost his government job. His name was Jim Berkland.
    • by Anonymous Coward

      I also remember reading about this theory ~10 years ago; i.e. that if the tidal forces from the sun and moon are strong enough to move the oceans around, they should also be strong enough to move the Earths crust a bit around, and then you've got yourself an earthquake. So it's not exactly news, more like new evidence in support of an existing theory.

  • Can anyone explain to me why the phase of the moon would have anything to do with its gravitational pull?

    • It's about tidal forces - the relative angles at which the sun and the moon are acting on the earth as the phases of the moon change. The overall strength of the moon's gravitational pull does not change, since its mass is constant.

    • Can anyone explain to me why the phase of the moon would have anything to do with its gravitational pull?

      The phase itself doesn't have any meaningful effect that I am aware of but the factors that cause the moon phase DO cause real changes in tides. Primarily orbit of the moon in relation to other bodies including the Earth. It isn't the phase per-se that causes the differences but the fact that phase and lunar orbit are closely related.

      Some examples:

      1) Tidal forces don't just come from the Moon. The Sun exerts significant tidal forces as well. The sum of these forces is dependent on the position (and by e

    • Thank you to everyone who answered. I forgot about the alignment with the Sun. It makes perfect sense.

  • by Anonymous Coward

    It's about time scientists started admitting that bad things DO happen at full moon.

  • by Qbertino ( 265505 ) <moiraNO@SPAMmodparlor.com> on Tuesday September 13, 2016 @10:41AM (#52878847)

    Forces of nature can trigger forces of nature.
    Film at eleven.

  • The moon causes ocean tides of several feet. It also causes land "tides" of several inches. This small flexing of the earth can set up conditions where a fault that is already under a lot of stress can release, resulting in an earthquake. Normal tectonic movements are the source of the stress that is slowly building up over time, but the flexing of the earth due to the sun and moon results in statistically higher releases of the stress around full and new moons. In other words, the fault was ready to ri

  • Well just think how we can magnify that by fracking on the moon...
  • pull on the moon (basic physics). And because global warming causes earthquakes, global warming affects the orbit of Earth's moon.
  • An earthquakes occurs when the static force of friction at a point of geologic stress is overcome, or when the force on a geologic structure exceeds its breaking point. It is an extremely non-linear response, which can be triggered by small changes in these forces. Given that, it would be surprising if tidal effects were not correlated with earthquakes.

    As the polar ice melts and its weight is redistributed over the oceans, I expect this also will result in sufficient changes in tectonic forces to trigger mo

    • by spitzak ( 4019 )

      I don't know if you are trying to make a joke, but global warming is not going to do too much to the earthquakes. Greenland is already rising steadily due to the loss of the glaciers from the last ice age. It is really slow and will still happen for tens of thousands of years. Even if all the current ice cap disappeared tomorrow it would, at best, speed this up a tiny amount (the current ice cap is a fraction of the ice age ice cap so the amount of lost mass is only a small change). The weight of the new ic

      • I'm talking about differentials in force with respect to a system capable of extremely non-linear responses. When polar ice melts, much of the weight that was on one plate moves to adjacent plate(s), so the force on the plate where the ice was decreases, and the force on the adjacent plate(s) increases. The change in the difference in force between the plates could exceed the weight of the ice. (And it could be a positive or negative change, depending on the relationship of the plates. A negative change cou

  • Didn't we already know this? The moon can cause tides, earthquakes, and other Earth-bound changes.
  • If the Bitcoin guy says the gravitational pull of the moon can trigger major Earthquakes, I believe him!

  • That's no moon!

  • They're divine punishment to us all for allowing homosexuals and assorted heathens to run amok! It's true. It's all there black and white clear as crystal.

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