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

[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

[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

[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

[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

[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.

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

[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: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.

Best name ever!

[mmatador22]

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

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.