Zipingpu Dam May Have Triggered the Sichuan Quake

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."

Comments

I am sick of it...

[Kjuib]

Those dam quakes always screwing everything up!

It would have likely occurred anyway

[EmbeddedJanitor]

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

[Gat0r30y]

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

[SoupGuru]

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

[corsec67]

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

[jd]

Given the current value of the pound, a few million would barely buy you enough to have an impact on a hydrophobe.

Re:It would have likely occurred anyway

[Brigadier]

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

[Anonymous Coward]

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

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

Re:It would have likely occurred anyway

[fugue]

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

[Fluffeh]

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:It would have likely occurred anyway

[adolf]

+5?

Geez. For that matter, as long as we're speculating, it could have made the quake much less intense.

Remember, kids: Just because you've changed something, doesn't mean that you've always made something else worse.

Re:It would have likely occurred anyway

[inKubus]

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

Re:It would have likely occurred anyway

[Anonymous Coward]

Suggest you better research the coffee spill incident. Car wasn't moving, complaints about temp filed more than once, much hotter than surrounding area restaurants, woman required skin grafts to repair damage and only sued for cost of medical bills after McD's blew her off. Lots of details glossed over concerning that incident but considering just how hot it was and the damage it did I don't think awarding ONE day's worth of coffee sales was that bad of a restitution... and that was later overturned.

There are certainly shitty lawsuits but THAT one was pretty deserved I think and a poor example despite your trying to be funny about it.

Re:It would have likely occurred anyway

[RodgerDodger]

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...

Re:It would have likely occurred anyway

[Hal_Porter]

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

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

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:It would have likely occurred anyway

[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 to the fault can, within a few years, show right lateral displacements of a foot or more due to the constant creep of the fault in that region. There is an Almaden winery formerly located on a similar slip zone north of San Francisco. Since the building was gradually coming apart because it straddled the fault and they feared a collapse, they relocated south to Hollister. Unfortunately they again located directly on the fault. You can see the same kind of displacement if you sight along the long side walls of the winery. The USGS now has a nice place out of the weather to keep their instrumentation -- it's located inside the building on both sides of the fault.

Re:Tragic, maybe?

[bennomatic]

Or maybe it could have been, "Have it smaller." I wonder if we'll ever know.

I feel a bad movie based on this where need to blo

[Joe The Dragon]

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

Prediction

[philspear]

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

[peragrin]

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

[philspear]

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.

Re:Prediction

[stephanruby]

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

[Malc]

Hessler's River Town: Two Years on the Yangtze 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

[philspear]

What are you talking about? That post was 100% not sarcastic! Higher praise for the chinese government has never been seen on slashdot!

Re:Prediction

[Anonymous Coward]

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

[CrimsonAvenger]

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.

Re:Prediction

[Malc]

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 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.

Re:Social justice requires desalination

[Orne]

This is the country that strictly enforces a one-child-per-family law, and you think the Chinese government actually wants more people to take care of?

No surprise

[Locke2005]

Haven't we known for 40 years now that injecting water into a fault can trigger a quake?

Re:I feel a bad movie based on this where need to

[Chabo]

Sir Ranulph Fiennes (the famous arctic explorer, among other things) was actually kicked out of the SAS for destroying a dam using stolen explosives. You can google for more detailed accounts of the story, but here's one:

http://www.independent.co.uk/student/career-planning/getting-job/my-first-job-explorer-sir-ranulph-fiennes-was-an-sas-officer-420601.html

the government is blameless

[circletimessquare]

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?

[Hans Lehmann]

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?

[khallow]

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.

Re:quid pro quo

[Jurily]

Don't worry, I'll find a way.

Sincerely, Nature

Re:Social justice requires desalination

[Locke2005]

That effect was disproportionate on the poor.

Every natural disaster has a disproportionate effect on the poor! That's just one of the many, many reasons why it sucks to be poor!

Re:Social justice requires desalination

[stephanruby]

This earthquake killed a lot of people and ruined the lives of countless others. That effect was disproportionate on the poor.

This earthquake killed less than 100,000 people.

In 1931, the flooding of a different river (the Yellow river) killed 3.7 millions. And thirty years before that, another flood in China killed 1 million people.

Flooding kills poor people. Dams prevent flooding.

Re:Tragic, maybe?

[Anonymous Coward]

The lil' sob's probably won't hear anyway, what with their loud music, and their hippin an their hoppin, and their bippin and their boppin.

GET OFF MY LAWN!

Best name ever!

[mmatador22]

Hahahaha - Zipping Poo... Best name for a dam ever!

Re:Tragic, maybe?

[im_thatoneguy]

Won't be able to. Remember? Dead.

Re:Social justice requires desalination

[LWATCDR]

Sorry folks.
They would have been better off if they hadn't elected the idiot Mayor and Governor.
People like to blame FEMA but FEMA did they typical job. The local and state governments where criminal.
It was the local government that failed to use the school buses to evacuate the people. Heck they even left them in the flood plane. My city has been hit by three storms. The School buses are always moved to stageing areas near shelters. The state government put police out side New Orleans to keep the people IN after the storm.
Heck the state didn't even have shelters for all the people. Texas had to provide shelters.
What really ticks me off is people forget about Mississippi. They took the worst hit for Katrina. They had a HUGE store surge that took out whole sections of their coast line. They had many homes whipped out but you don't see people up in arms because their state and local governments where a lot more effective.
What is the worst part. That idiot moron of a mayor GOT REELECTED!!!!!!!!!!!

Re:Social justice requires desalination

[couchslug]

"This earthquake killed a lot of people and ruined the lives of countless others. That effect was disproportionate on the poor."

Chinese poor have always been expendable. They are easily replaced, and their rulers have always understood this.

Re:Social justice requires desalination

[Toonol]

What is the worst part. That idiot moron of a mayor GOT REELECTED!!!!!!!!!!!

And, bringing it around full circle, electing terrible leadership is a consequence of being poor and uneducated. The people re-electing the mayor bought the line that the federal government was primarily responsible for the mishandling, and probably made a Bush joke or two... not understanding what role the state and federal governments were supposed to play.

The feds should be thanked for cleaning up the mess Louisiana got itself into.

NASA math at work. And yes,IAANB*

[rts008]

Maybe they can get this drilling crew on the mission to save the day!

All humour aside, most people have no clue about the energy levels and destructive power available to natural forces, just on our world. (ie:water) Even engineers can fall prey to their preconceptions at times, if they are not diligent. Water is a powerful force, in scale.

Most people perceive the Earth as a solid/stable surface to build on(dig to 'bedrock' for the foundation, etc...), frequently forgetting Earth more resembles a poultry egg: relatively thin shell covering/encasing a liquid center...and just as fragile on scale.

At our most terrible destructive level available technologically to humans today, we are still just 'wannabe' punks in the big picture. Actually, I would argue that communication tech is the most powerful weapon/tech we have devised to date.

*(IAANB) I Am A NASA Brat![clarification of subject line]-just could not pass this one up. And NOT trying to pick on engineers, who have demanding job requirements, but there is a good reason to put erasers on pencils! :-)

Sorry if this was more than you bargained for trying to make a 'funny', but you did raise a valid point! :-)

Re:Social justice requires desalination

[Trailer Trash]

Dams don't prevent flooding. They just move it somewhere else.

Right, and we know exactly where that somewhere else is (right behind the dam) and we don't build houses there anymore because it's a lake.

Dams prevent catastrophic, uncontrolled flooding by buffering the surge in a lake and letting it out slowly. The Ohio River no longer floods because of the hundreds of artificial lakes created in its watershed, for instance.

Paeleoseismology

[penguinchris]

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/) 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 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

I AM SICK

[GameboyRMH]

Of these muthafuckin' QUAKES on this muthafuckin' (fault)PLANE!!!