Slashdot is powered by your submissions, so send in your scoop

 


Forgot your password?
Close
typodupeerror
×
Earth Government News Science

Zipingpu Dam May Have Triggered the Sichuan Quake 193

Posted by kdawson from the may-get-us-banned-in-china dept.
bfwebster writes "An article in the Telegraph (UK) raises an interesting question: was the massive (7.9) Sichuan earthquake that wracked China last year and left millions homeless caused by ground stresses following the completion of the Zipingpu dam? As the article notes, 'The 511-ft-high Zipingpu dam holds 315 million tonnes of water and lies just 550 yards from the fault line, and three miles from the epicenter, of the Sichuan earthquake. Now scientists in China and the United States believe the weight of water, and the effect of it penetrating into the rock, could have affected the pressure on the fault line underneath, possibly unleashing a chain of ruptures that led to the quake.'" The Sichuan region is earthquake-prone, but has not seen anything as large as the 7.9-magnitude quake for perhaps millions of years. The Chinese government denies any connection between the dam and the earthquake and seems to be actively obstructing the access of scientists who want to investigate. The article concludes, "There is a history of earthquakes triggered by dams, including several caused by the construction of the Hoover Dam in the US, but none of such a magnitude."
This discussion has been archived. No new comments can be posted.

Zipingpu Dam May Have Triggered the Sichuan Quake More

Zipingpu Dam May Have Triggered the Sichuan Quake

Comments Filter:

  • I am sick of it... (Score:5, Funny)

    by Kjuib ( 584451 ) on Tuesday February 03, 2009 @07:00PM (#26718501) Homepage Journal

    Those dam quakes always screwing everything up!

  • It would have likely occurred anyway (Score:5, Interesting)

    by EmbeddedJanitor ( 597831 ) on Tuesday February 03, 2009 @07:03PM (#26718537)
    The dam might have just brought the event forward a year or two. Fault lines are natural stress relief areas anyway.

    As with all things geological, there are a lot of unknown variables, hence the "could", "might" and other diluting terms.

    • Re:It would have likely occurred anyway (Score:5, Interesting)

      by Gat0r30y ( 957941 ) on Tuesday February 03, 2009 @07:12PM (#26718625) Homepage Journal
      I suspect that when as much energy as was released in that particular quake gets released, it was gonna get out one way or another. But building the dam where they did couldn't have helped.

      • Re:It would have likely occurred anyway (Score:5, Insightful)

        by fugue ( 4373 ) on Tuesday February 03, 2009 @08:36PM (#26719485) Homepage

        It could indeed have helped. There was a proposal a few years ago to inject water into faults, the idea being that this would lubricate the faults and trigger quakes sooner. That, of course, means more smaller quakes, rather than fewer really big ones.

        Probably never came to anything due to liability concerns. Letting nature kill a few thousand is better than a human doing something that kills one who has a good lawyer. Woot. Unless it's burning fossil fuels, I suppose... never mind...

        • Re:It would have likely occurred anyway (Score:4, Insightful)

          by inKubus ( 199753 ) on Tuesday February 03, 2009 @11:26PM (#26720739) Homepage Journal

          Interesting you should mention fossil fuels as there's a strong correlation between earthquakes and oil extraction (and other mining activities)..

        • "liability concerns" ... this is in China... I think if they have a single victim of some state organized action and encounter a good lawyer in that context, they resolve this by beatings or executions. Remember this is a country which moves over a million people in order to build a dam somewhere: http://en.wikipedia.org/wiki/Three_Gorges_Dam#Relocation_of_local_residents [wikipedia.org]

          • Re:It would have likely occurred anyway (Score:5, Informative)

            by Hal_Porter ( 817932 ) on Wednesday February 04, 2009 @05:30AM (#26722641)

            Actually they have a much more elegant way of resolving things like this

            http://www.taipeitimes.com/News/front/archives/2009/02/03/2003435140 [taipeitimes.com]

            A Chinese dissident who was arrested after campaigning for the parents of children killed in the Sichuan earthquake will stand trial on state secret charges, his wife and lawyer said.

            The abrupt announcement that Huang Qi , 45, would be tried came nearly eight months after he was detained as authorities silenced criticism about fragile school buildings that collapsed on children in the May 12 quake.

            "This morning I received a phone call from the court ... to ask me to tell Huang Qi's lawyers that he will be put on trial on Tuesday [today] for illegal possession of state secrets," Huang's wife Zeng Li told reporters by phone yesterday.

            Later, Huang's lawyer Mo Shaoping said that the district court in Chengdu, capital of Sichuan Province, had agreed to push back the trial date after attorneys protested they had not been given enough time to prepare.

            "The court must warn the defense side three days before," he said, adding that he did not know when the trial would begin.

            Huang was detained in Chengdu on June 10 â" about a month after the 8.0-magnitude earthquake left more than 87,000 people dead or missing.

            Huang, a long-time rights activist who used the Internet to publicize his causes, had started to campaign for parents whose children were killed when their schools collapsed in the quake.

            About 7,000 schools were destroyed, often as nearby buildings stood firm, and relatives of the dead children initially spoke out loudly against the graft they believed led to shoddy construction.

            "Up to now, we still have not been able to see the [specific] charges" against Huang, Mo said.

            Zeng said Huang's arrest was a result of his work in the earthquake zone.

            "This is because he went to the disaster area a couple of times. He reported on the shoddy schools and reported about the appeals of the parents of the students. So he was arrested and charged with possessing state secrets," she said.

            The ill-defined charge is often used to clamp down on dissent and send activists to prison.

        • Re: (Score:2, Interesting)

          by Anonymous Coward

          The waste water injection that they did at the Rocky Mountain Arsenal in Colorado is a well known example (several decades old though). See here: http://www.nyx.net/~dcypser/induceq/iis.html

        • Re: (Score:3, Informative)

          by Anonymous Coward

          That, of course, means more smaller quakes, rather than fewer really big ones.

          The effect is negligible. The Richter scale is logarithmic. On a geological tour of the Hollister, California area, which is in a slip zone on the San Andreas fault, the tour guide, a geology prof at Foothill College, explained that minor quakes on a fault don't release enough total energy to make any appreciable difference in the ultimate magnitude or timing of a big one in the same area.

          In Hollister, sidewalks built crosswise

    • Re:It would have likely occurred anyway (Score:5, Funny)

      by SoupGuru ( 723634 ) on Tuesday February 03, 2009 @07:17PM (#26718697)

      Yeah, I have a hard time believing a couple million pounds of water has much impact on the geologic energies stored up along the fault.

      I'll bet what actually happened is that all the Chinese jumped at the same time.... that would definitely do it.

    • Re:It would have likely occurred anyway (Score:4, Interesting)

      by corsec67 ( 627446 ) on Tuesday February 03, 2009 @07:32PM (#26718877) Homepage Journal

      The dam might have just brought the event forward a year or two.

      Or made it much more intense. Maybe without the dam and lake instead of one large earthquake it would have been a series of smaller earthquakes.

      Adding a large weight almost on top of a fault is definitely going to influence it, flexing the Earth and altering the stresses in the fault.

    • Re:It would have likely occurred anyway (Score:4, Interesting)

      by Brigadier ( 12956 ) on Tuesday February 03, 2009 @07:39PM (#26718939)

      true, yes the damn may have caused the earthquake, but the proper way to look at it is the earthquake brought the geology back to a neutral point. so technically they should be in a good place.

      plus the fact the damn did not fail, says it was built properly.

      • Re:It would have likely occurred anyway (Score:5, Interesting)

        by Fluffeh ( 1273756 ) on Tuesday February 03, 2009 @08:47PM (#26719577)

        but the proper way to look at it is the earthquake brought the geology back to a neutral point

        Why on earth would you say that? Earthquakes don't bring geology to neutral points. They happen when the earth gets past critical point.

        I can't think of a totally slashdot car analogy, but here is a good analogy of earthquake causes and how it works geologically that at least includes a car.

        Think of a piece of bungee cord 10 meters in length. You tie one part to the tow-ball of a car, and hold the middle of the cord. This means there is five meters of slack cord past the point where you are holding. Now, the car very very slowly starts to drive away from you, and the tension in the cord slowly grows. You holding onto the cord with all your might represents the pressures on the fault line. Sooner or later however, the pull on the cord will be too much, and it will slip in your hand. Now, you don't totally let go however. It might slip an inch or two, just barely enough so that the force of your hand holding it once again overcomes the force of the pull in the cord - but there is still a lot of tension in the cord. When the car moves away far enough again, there will be another slip of a small distance again and again.

        This is how fault lines work. When there is a quake, it doesn't go back to a neutral point. It goes back to a point which is lower than the critical point that caused the earthquake.

        • Re: (Score:2)

          by Toonol ( 1057698 )

          I'm not sure the GP post merited your correction, which ended up saying (this is a paraphrase): "It doesn't return to a neutral point, just closer to a neutral point."

        • we're essentially saying the same thing ie earthquakes release tension in the system. In this case the damn may have been a catalyst. In one sense it may have allowed the tension to be released as opposed to continuing to build up and have a catastrophic earthquake 100 years from now.

          If I understand correctly you are better of with many small earthquakes, as opposed to one huge one.

    • Re:It would have likely occurred anyway (Score:5, Informative)

      by Anonymous Coward on Tuesday February 03, 2009 @07:48PM (#26719023)

      "The dam might have just brought the event forward a year or two."

      Or decades, or centuries. It's hard to be sure yet. As the article mentions, there is ample precedent [internationalrivers.org] for earthquakes being triggered by the weight of the water behind dams and increase in pore fluid pressure, both in seismically active and relatively inactive areas. If you want to find papers, look for the term "reservoir-induced seismicity". In the high activity case, yeah, maybe it didn't make much difference, because the area could have frequent earthquakes anyway, but in the latter case (less active area) it can make a big difference versus the natural earthquake pattern. Having major earthquakes where they didn't happen before (in human memory) is pretty inconvenient.

      Because the earthquake did happen in a fairly seismically active part of China, people should be cautious about interpreting too much into its location near a dam. For an earthquake that big the stress must have built up over a long period of time -- far longer than the dam has been around. It couldn't have been the sole cause. It is still a legitimate question that deserves further study.

      This paper [sc.edu] [PDF] gives a good description of the physics and evidence behind the process with an example from the Montecello reservoir [sc.edu] [PDF] in South Carolina.

      This paper [springerlink.com], which unfortunately requires a subscription to read, talks specifically about reservoir-induced seismicity in China [springerlink.com], especially in regards to the Three Gorges Dam project. It dates from 1998.

    • Re:It would have likely occurred anyway (Score:4, Interesting)

      by RodgerDodger ( 575834 ) on Wednesday February 04, 2009 @02:56AM (#26721891)

      It could also have resulted in the stress being accumulated faster than the normal release mechanisms could offset. The FA suggests that the stress was roughly "25 times the normal tectonic movement for a year" - so instead of having a dozen or so non-damaging quakes every couple of years, they got one big one.

      Who knows? Too many variables...

  • Well, it's either have the earthquake now or have it later. Take your pick.

  • I feel a bad movie based on this where need to blo (Score:4, Insightful)

    by Joe The Dragon ( 967727 ) on Tuesday February 03, 2009 @07:06PM (#26718583)

    I feel a bad movie based on this where need to blow up dam to stop a super quake from happening is coming.

  • Prediction (Score:5, Funny)

    by philspear ( 1142299 ) on Tuesday February 03, 2009 @07:07PM (#26718587)

    Chinese officials will conclude that the scientific findings are acurrate and convincing, will acknowledge that the dam did cause the quake, will apologize sincerely, and resign in disgrace. The replacements will then close down the dam, making sure to dismantle it in an ecologically sensible way, doing the least disruption to the surrounding communities as well, and every victim of the quake will be compensated accordingly. You know, much as it would happen here.

    You really have to love government humility and responsibility.

    • Re:Prediction (Score:5, Interesting)

      by peragrin ( 659227 ) on Tuesday February 03, 2009 @07:19PM (#26718713)

      not to dodge your sarcasm, but the scientific findings are vague enough to blame the entire quake on Bush bombing people in iraq.

      you never know what that one last MOAB will really do what with the butterfly effect and everything.

      also if a quake hasn't happened in a million years then it just might be under a lot of stress, that doesn't easily go away.

      • Re:Prediction (Score:4, Interesting)

        by philspear ( 1142299 ) on Tuesday February 03, 2009 @07:25PM (#26718789)

        Oh yeah, I was of course sidestepping the issue of "Is the finding ACTUALLY valid." Somewhat like what the chinese government will do, only they probably won't do it with sarcasm. It'd be refreshing if they did though.

        • heck I am waiting for the USA government to admit they screwed up once, then hell really will be frozen over.

          • Re:Prediction (Score:5, Funny)

            by CrimsonAvenger ( 580665 ) on Tuesday February 03, 2009 @10:57PM (#26720553)

            heck I am waiting for the USA government to admit they screwed up once, then hell really will be frozen over.

            Oh, please! The US government admits it screwed up regularly. Pretty much every time an new President is elected, he admits his predecessor screwed up.

          • Obama just said, "I screwed up." I hear that Hell is expecting it first blizzard shortly.

    • Re:Prediction (Score:5, Funny)

      by stephanruby ( 542433 ) on Tuesday February 03, 2009 @07:28PM (#26718823)
      Thanks a lot man! because of your comment, I won't be able to read slashdot the next time I'm over there.

    • Re:Prediction (Score:5, Informative)

      by Malc ( 1751 ) on Tuesday February 03, 2009 @07:38PM (#26718927)

      Hessler's River Town: Two Years on the Yangtze [amazon.co.uk] is a great account of an American journalist living in China in an area to be flooded by the Three Gorges Dam. He quite clearly articulates how the people of China passively accept things like this. It's a great read, especially if you've even been to the country. Quite often though, the people think their government is correct and efficient, and that you have to accept some inconvenience for a better future for all. As always, the government is a symptom of the people, and vice-versa.

      • Re:Prediction (Score:4, Insightful)

        by Anonymous Coward on Tuesday February 03, 2009 @09:39PM (#26720005)

        Back in the 40s and 50s Americans also used to just sigh and call it the "Price of progress." There used to be widespread acceptance of infrastructure development. Attitudes started changing in the 60's and 70's. It's a lot easier to be against infrastructure development when you live in a nation with well developed infrastructure.

        • Re:Prediction (Score:5, Interesting)

          by Malc ( 1751 ) on Wednesday February 04, 2009 @12:01AM (#26720977)

          Yes, that's so true. The changes that China has gone through in the last 100 years are staggering. Edgar Snow's Red Star Over China [google.ca] gives a fantastic account of what China was like during the Communist Revolution. It brought them forward a millennia in a few years, spreading education, and raising standards for 100 of millions of poor Chinese peasants. But that still left China far behind what we consider a well developed country. Of course, the Great Leap Forward and Cultural Revolution didn't really help. Then again in the last ten or fifteen years, it's almost as if China has come forward another millennia, where cities like Shanghai are fairly easy to live in as Westerner. The people there are now beginning to resist change for this reason. Want to build a new Maglev line to Hangzhou or high speed rail link to Beijing? The people organised together and forced the government to re-route it via somebody else's neighbourhood. Out in the country though, people still put up with being relocated because their lives haven't changed as fast and are some way behind.

    • You know, much as it would happen here.

      You really have to love government humility and responsibility.

      Well ... Blowout Taking down a dam used to require an act of Congress-or terror. Now it's just good business. [away.com] No comment - just relevant.

    • Re: (Score:2)

      by Toonol ( 1057698 )
      Why dismantle the dam? The earthquake has already happened, presumably dissipating the additional stress caused by it's presence.

      Removing the dam would probably destabilize the geology, at this point.

  • No surprise (Score:5, Informative)

    by Locke2005 ( 849178 ) on Tuesday February 03, 2009 @07:13PM (#26718653)
    Haven't we known for 40 years now that injecting water into a fault can trigger a quake [time.com]?

  • let's say they know dams cause earthquakes. ok, so there will be some minor earthquakes. but 7.9? no one is going to predict anything that large

    still, let's assume the dam is still the trigger for the 7.9 earthquake. emphasis on trigger. its going to happen someday anyway

    if they never built the dam, we'd be talking about the 7.9 or 8.3 sichuan earthquake of 2031 or 2102

  • How do they know it's never happened before? (Score:5, Interesting)

    by Hans Lehmann ( 571625 ) on Tuesday February 03, 2009 @07:30PM (#26718847)
    The Sichuan region is earthquake-prone, but has not seen anything as large as the 7.9-magnitude quake for perhaps millions of years

    Would a 7.9 quake, although large by earthquake standards, even leave evidence that lasted more than, say, 1000 years? You might be able to tell if you took a cross section of the entire fault line, I suppose, but not all fault lines are known. A L.A. city geologist found a previously unknown (but not currently active) fault under the house of a friend of mine when he was having some drainage work done; new ones are discovered all the time.

    • Re:How do they know it's never happened before? (Score:4, Interesting)

      by khallow ( 566160 ) on Tuesday February 03, 2009 @09:40PM (#26720019)

      Yes, it would. Off the top of my head, I can think of two classic examples in the US easily visible to regular people, the San Andreas fault and the thrust fault that forms the steep eastern face of the Grand Tetons. In each case, it's easy to figure out how much the fault has moved each time an earthquake occurs. For example, the San Andreas fault slides sideways during an earthquake and displaces streams and geographical features. I believe that they can trace to some degree the earthquake record for the past few thousand years. Similarly, the face of the Grand Teton mountains lifts after each major quake, exposing a fresh patch of earth and rock. I dimly recall they have dated these giving an estimate of a magnitude 7 earthquake every 400-700 years.

      My belief is that if the geological record for earthquakes were studied properly, we would find that a magnitude 7.9 earthquake is indeed typical for that particular fault (much less the area). It's quite possible that the dam was the trigger for the quake, but it's not so likely that it amplified the energy release of the quake. If it did, however, I would guess wildly that the mechanism would be reduced energy loss to friction.

      • Paeleoseismology (Score:4, Interesting)

        by penguinchris ( 1020961 ) <.moc.liamg. .ta. .sirhcniugnep.> on Wednesday February 04, 2009 @03:33AM (#26722135) Homepage

        Paleoseismology as you described is actually quite difficult. In the case of the San Andreas, you can't really look at off-set streams and such. You can rarely discern more than one or two events along such offsets, and once you do, it is very difficult to determine the age of the offset. You can get the amount that it's moved, yes, but not the timing. Worse, since you don't know the timing, you don't know if the offset is from one or more events.

        The way it's done for strike-slip faults like the San Andreas is to look at a cross-section perpendicular to the fault, looking for layers of material off-set (or suddenly changing thickness, etc.) along the fault. The best way to date those layers is through carbon-14 dating of organic material, which can give you accuracy only within ~1-200 years - and that's assuming that the organic material you date is not from elsewhere, is not from 200 year old trees, etc. If an event offsets every layer from the bottom up to a certain point, you date the top layer that it cuts through to get a maximum age, and the layer that it didn't cut through is the minimum age.

        You can imagine the difficulty and ambiguous nature of this. The individual layers that you have to recognize and date are on the scale of centimeters to decimeters - I've seen some of the areas that were used, the famous one being along Pallet Creek which is along the San Andreas northeast of LA (I have a picture of it - well, it is a picture of a girl standing in front of it - here: http://www.flickr.com/photos/penguinchris/3037578910/ [flickr.com]) Here, luckily there was constant, relatively rapid deposition of material. In most places this is not the case, so any record of movement on the fault is eroded away.

        For the San Andreas, we have a partial record going back ~1500 years. There really is no reliable way to reach back further than that - the record isn't normally visible in older rock units. Looking at the larger-scale structures is interesting by itself but doesn't tell you anything about when specifically there was movement. The fault system in the Sichuan region is fairly well understood - it is a kind of combination strike-slip/thrust fault (see http://quake.mit.edu/~changli/wenchuan.html [mit.edu] for some nice diagrams.) But I want to call BS on the idea that they have any idea how frequently major earthquakes have happened there - and even if they do, the idea that it is "perhaps millions of years" since the last one is ridiculous no matter what.

        And then, when you *do* figure out a approximate year for an earthquake, how do you determine how big it was? Again, extremely difficult! The best estimates come from comparing old written records of destruction with those from modern earthquakes - nothing scientific at all!

        What's being done extensively with the San Andreas is physics-based computer modeling - we have some idea of the force building up, and combining that with records of historical earthquakes we can make an estimate of a major earthquake every ~150 years. But even for this, the best-studied earthquake area, it's not much more than a guess.

        I don't know as much about the Teton fault (other than that it is a normal fault, not a thrust fault as you stated ;) ) but I'll comment on the idea of a "magnitude 7 earthquake every 400-700 years." These kinds of estimates are based on the very difficult work I described earlier (and I'm not sure how much has been done for the Teton fault) and whatever geologist came up with that would probably admit it is a simple guess without much to base it on. I mean, think of it - is knowing there's a large earthquake every 400-700 years really all that useful anyway?

        By the way, I assume any dating of the Teton fault would be done this way: when new patches of rock are exposed along the fault as you described, they start getting hit by cosmogenic radiation. By measuring the amount of cosmogenic radio isoto

        • Re: (Score:2)

          by khallow ( 566160 )

          Bah, this is almost as bad as some of my posts on fission reactor technology. Didn't realize I was so far off.

          I mean, think of it - is knowing there's a large earthquake every 400-700 years really all that useful anyway?

          I always thought the answer was "yes", if you live in the location long enough. An overnight in the Grand Tetons National Park? Not worth the bother. But if you're planning to buy a house and live there for 20 years. Even at the best case, that's 3% of the estimated time between earthquakes. I gather it's been a while since the last quake too. Not as bad as automobile accidents in likelihood, but it

    • Zhang Heng invented an earthquake detector in China in 132 AD, so yes. There is Chinese earthquake data going back well over 1000 years.

      • Re: (Score:2, Insightful)

        by amRadioHed ( 463061 )

        That earthquake detector was only for determining the direction of the quake, it could not measure the strength. And has it ever been determine if it even worked properly? I'm sure it was fine at detecting shaking that it had been shaked, but it seems to me that the direction wouldn't be very reliable.

  • Just Wait (Score:2, Interesting)

    by Anonymous Coward

    If this is true, then just wait until the Three Gorges begins to top off (it has been filling for years now and has some time to go.)

  • Best name ever! (Score:5, Funny)

    by mmatador22 ( 1230758 ) on Tuesday February 03, 2009 @08:19PM (#26719331)
    Hahahaha - Zipping Poo... Best name for a dam ever!

  • has not seen anything as large as the 7.9-magnitude quake for perhaps millions of years

    Yes but records only go back for a few thousand years, when the hall of records was mysteriously destroyed somehow.

    (with apologies to the Simpsons)

  • About 20 years ago a US Geological Survey scientist noted the associated of several large California earthquakes and large oil production. He cited the same principles as in the this dam case and showed some calculations. But its hard to rule out other factors and prove this conclusively.

  • Metric (Score:2, Insightful)

    by daem0n1x ( 748565 )

    The 511-ft-high Zipingpu dam holds 315 million tonnes of water and lies just 550 yards from the fault line

    China (and by the way the rest of the world except USA, Burma and Liberia) uses the metric system. Your numbers sound like chinese to me and most of the world population.

  • Or not.

    Do some science and get an answer to the question.

Slashdot Top Deals

Anyone can make an omelet with eggs. The trick is to make one with none.

Close