Zipingpu Dam May Have Triggered the Sichuan Quake 193
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."
No surprise (Score:5, Informative)
Re:Prediction (Score:5, Informative)
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:It would have likely occurred anyway (Score:5, Informative)
"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:Social justice requires desalination (Score:5, Informative)
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:It would have likely occurred anyway (Score:5, Informative)
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:It would have likely occurred anyway (Score:3, Informative)
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.