Did The Zipingpu Dam Cause The Sichuan Earthquake?
Science: A Human Trigger for the Great Quake of Sichuan? Richard A. Kerr and Richard Stone
Natural disasters are often described as "acts of God," but within days of last May's devastating earthquake in China's Sichuan Province, seismologists in and out of China were quietly wondering whether humans might have had a hand in it. Now, the first researchers have gone public with evidence that stresses from water piled behind the new Zipingpu Dam may have triggered the failure of the nearby fault, a failure that went on to rupture almost 300 kilometers of fault and kill some 80,000 people.Still, no one is near to proving that the Wenchuan quake was a case of reservoir-triggered seismicity. "There's no question triggered earthquakes happen," says seismologist Leonardo Seeber of the Lamont-Doherty Earth Observatory in Palisades, New York. That fact and the new evidence argue that the quake-dam connection "is worth pursuing further," he says, but proving triggering "is not easy." And the Chinese government is tightly holding key data.Seismologists have been collecting examples of triggered seismicity for 40 years. "The surprising thing to me is that you need very little mechanical disturbance to trigger an earthquake," says Seeber. Removing fluid or rock from the crust, as in oil production or coal mining, could do it. So might injecting fluid to store wastes or sequester carbon dioxide, or adding the weight of 100 meters or so of water behind a dam.Whatever the nature of the disturbance, it must bring a nearby fault to the point of failure to trigger a quake. In the case of reservoir-triggered seismicity, the water's weight can weaken a fault by counteracting the stresses that are squeezing the two sides of the fault together and tightly locking it. Or, the added weight can increase the stress already tending to push opposing sides past each other and break the fault. In 1967, impoundment behind the Koyna Dam in India triggered the largest known reservoir-triggered quake, a magnitude-6.3 temblor that killed 200 people. Seismologists recognize dozens of other reservoir-triggered quakes in the range of magnitude 3 to 6.So when the magnitude-7.9 Wenchuan earthquake struck, many scientists wondered if a reservoir was to blame. Ruling out the much-maligned Three Gorges Dam as too distant, experts considered the Zipingpu Dam, just 500 meters from the fault that failed and 5.5 kilometers from the quake's epicenter. The timing was right. The Zipingpu reservoir began filling in December 2004, and within 2 years the water level had rapidly risen by 120 meters, says Fan Xiao, a chief engineer of the Sichuan Geology and Mineral Bureau in Chengdu.
The several hundred million tons of water piled behind the Zipingpu Dam put just the wrong stresses on the adjacent Beichuan fault, geophysical hazards researcher Christian Klose of Columbia University said at a session last month at the Fall Meeting of the American Geophysical Union in San Francisco, California. In his talk, Klose coyly explained--without ever mentioning a dam--how the added water changed the stresses on the fault. According to his calculations, the added weight both eased the squeeze on the fault, weakening it, and increased the stress tending to rupture the fault. The effect was 25 times that of a year's worth of natural stress loading from tectonic motions, Klose said. When the fault did finally rupture, it moved just the way the reservoir loading had encouraged it to, he noted.Klose's listeners were intrigued but far from convinced. They wanted to hear more details about changing water levels and local, lower-level seismicity. Fan, who was not at the meeting, provides some of those details, all of which favor a link between the Zipingpu Reservoir and the earthquake. Judging by the history of known reservoir-triggered quakes, the rapid filling of Zipingpu as well as its considerable depth would have favored triggering, he says. The delay between filling and the great quake would have given time for reservoir water to penetrate deep into the crust, where it can weaken a fault. And the greatest danger of triggering comes not at the time of maximum filling, he argues, but when the water level is falling. "As we now know, a week before the May 12 earthquake, the water level fell more rapidly than ever before," says Fan.A paper in last month's issue of the Chinese journal Geology and Seismology arrives at a similar conclusion. Zipingpu's impoundment "clearly affected local seismicity," says lead author Lei Xinglin, a geophysicist at the China Earthquake Administration in Beijing and the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan. Lei emphasizes that a firm conclusion is premature, but he sees penetration of reservoir water into the fault and the reservoir decline between December 2007 and May 2008 as "major factors associated with the nucleation of the great Sichuan earthquake."Fan also does not see the Zipingpu-Wenchuan connection as proven yet, but he's seen enough to urge caution. "We should readjust our existing plans and take a more cautious attitude when planning projects," he says. "But I am pessimistic that many of these large-scale constructions will be canceled, because of the strong economic interests that benefit hydropower developers and local governments."Building a stronger case for restraint, researchers in and out of China say, will require access to even more detailed data. "Time-variation evidence for seismicity of small earthquakes near and surrounding the reservoir, as well as for the water levels and loading of the reservoir, are needed," says geophysicist Wen Xue-ze of the Sichuan Seismological Bureau in Chengdu. Fan believes that researchers in the Chinese Academy of Sciences have preliminary results from such studies, "but they are reluctant to share them."
(Telegraph) Chinese earthquake may have been man-made, say scientists. Malcolm Moore. February 3, 2009.
The 511ft-high Zipingpu dam holds 315 million tonnes of water and lies just 550 yards from the fault line, and three miles from the epicentre, 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.
Fan Xiao, the chief engineer of the Sichuan Geology and Mineral Bureau in Chengdu, said it was "very likely" that the construction and filling of the reservoir in 2004 had led to the disaster. "There have been many cases in which a water reservoir has triggered an earthquake," said Mr Fan. "This earthquake was very unusual for this area. There have been no seismic activities greater than a magnitude seven quake along this particular seismic belt before."
The 7.9 magnitude quake struck last May and left more than five million people homeless. It remains a raw and emotional topic for most Chinese, and the government has been quick to quash any suggestion that Zipingpu may have been responsible for the catastrophe. Researchers have been denied access to seismological and geological data to examine the earthquake further.
Zipingpu is only one of nearly 400 hydroelectric dams in the earthquake zone. Mr Fan said the government had been warned of the danger of building so many large-scale projects in a seismically active area, but that the warnings had gone unheeded. "I not only opposed the construction of Zipingpu, but also the overdevelopment of the reservoirs on Minjiang River. There are ten major reservoirs on the main river, 29 on its tributaries and a lot more smaller-scale reservoirs, all of which block the flow of the entire river, and are very hazardous to the local geology," he said.
Although Sichuan is an earthquake-prone region, many scientists were caught by surprise by the magnitude of the quake. Christian Klose, a scientist at Columbia University's Lamont-Doherty Earth Observatory, said there had not been any "major seismic activity" on that fault line for millions of years. He argued that the sudden shift of a huge quantity of water into the region could have simultaneously relaxed the tension between the two sides of the fault, allowing them to move apart, and also increased the direct pressure enough to cause a violent rupture. The effect was "25 times more" than a year's worth of natural stress from tectonic movement, he said.
Although the official government line is that its massive construction projects had nothing to do with the quake, some state researchers in Beijing have called for a full investigation. Lei Xinglin, of the China Earthquake Administration, said that the Zipingpu reservoir "clearly affected the local seismicity and it is worthwhile to study the role it played in triggering the earthquake further". He added that firm conclusions remain "premature" however.
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.
(Letter from China) Early Warning. By Evan Osnos. The New Yorker. February 6, 2009.
In the fall of 2006, I was wrapping up a month-long trip in Sichuan province, writing about life in the rapidly-changing Yangtze River valley. My final interview was with a geological engineer named Fan Xiao, whose cell-phone number had been given to me by a local environmentalist. I met Fan at his dank, half-lit office in an obscure government building in the city of Chengdu. He was soft-spoken and technical, but also surprisingly candid in his concern about the speed with which Chinese authorities were building dams on the rivers of Sichuan. Later, I quoted him in a story, in which he argued that the social unrest surrounding controversial dams could be avoided with more transparency. “In the future, the decision shouldn’t just be made by the developer and the government. The government should represent the whole civil society and all interest groups,” he had told me. As an aside, he also mentioned a geological detail: the potential impact that dams could have on earthquake patterns. But I lacked the wit to probe any deeper. Besides, it seemed impossible to imagine.
This week, Fan Xiao found himself in the New York Times, and at the center of a politically volatile issue with his contention that a reservoir near the fault line of the Sichuan earthquake last year may have triggered or hastened the quake. His findings and related conclusions by Columbia University scientists are not definitive, but, as they circulate in the West, they remain, so far, absent from the Chinese press, as far as I have seen. That’s probably because the prospect of any confirmed link is highly sensitive to the Chinese government, which has overseen the widespread construction of similar projects; China is now home to half the world’s large dams. To understand what that really means, click on this map, which highlights the sheer number of dams in Sichuan province. You’ll find the Zipingpu reservoir, the one being blamed in the Sichuan earthquake, in the upper-right corner. But it’s easy to miss; it’s just a single yellow dash among dozens.
(New York Times) Possible Link Between Dam and China Quake. By Sharon LaFraniere. February 6, 2009.
Nearly nine months after a devastating earthquake in Sichuan Province, China, left 80,000 people dead or missing, a growing number of American and Chinese scientists are suggesting that the calamity was triggered by a four-year-old reservoir built close to the earthquake’s geological fault line.
A Columbia University scientist who studied the quake has said that it may have been triggered by the weight of 320 million tons of water in the Zipingpu Reservoir less than a mile from a well-known major fault. His conclusions, presented to the American Geophysical Union in December, coincide with a new finding by Chinese geophysicists that the dam caused significant seismic changes before the earthquake.
Scientists emphasize that the link between the dam and the failure of the fault has not been conclusively proved, and that even if the dam acted as a trigger, it would only have hastened a quake that would have occurred at some point.
Nonetheless, any suggestion that a government project played a role in one of the biggest natural disasters in recent Chinese history is likely to be politically explosive.
The issue of government accountability and responsiveness has boiled over in China in the past year. The grieving parents of thousands of schoolchildren killed in the disaster have already made the 7.9-magnitude earthquake a political issue, charging that children died needlessly in unsafe school buildings approved by negligent or corrupt officials.
More public anger erupted last year when the government failed to prevent the sale of tainted milk powder that sickened nearly 300,000 children and killed six.
“Any kind of government-related disaster presently is very, very damaging and politically extremely sensitive,” said Cheng Li, the China research director at the Brookings Institution.
If it is proved that the earthquake “was related to a man-made situation and not just a natural disaster, the government will be very uncomfortable with that kind of report because of the whole issue of government accountability,” Mr. Li said.
Questions about the Zipingpu Dam are especially delicate because China is building many major hydroelectric dams in the southwest, a region which has abundant water resources but is considered prone to earthquakes.
In a petition to the government in July, a group of environmentalists and scholars said the fact that government scientists had underestimated the risk of the May earthquake raised questions about a host of other dams built in the same valley and along five other major rivers, according to an article published by Probe International, an environmental advocacy group. Chinese authorities have steadfastly dismissed any notion that reservoir-building in Sichuan Province placed citizens at any added risk, and they have blocked some Web sites of environmental groups that suggest that dangers have been overlooked.
In a December article in the Chinese magazine Science Times, two scientists from the Chinese Academy of Sciences strongly denied that the dam played any role in the earthquake. “The earthquake research community outside and inside China has widely accepted the notion that the May 12 Wenchuan earthquake was a huge natural disaster caused by massive crustal movement, because no reservoir triggered-quake with a magnitude eight has ever occurred in history,” said Pan Jiazheng, an expert in hydroengineering, according to a translation published by Probe International.
Scientists generally agree that a reservoir, no matter how big, cannot by itself cause an earthquake. But Leonardo Seeber, a senior scientist with the Lamont-Doherty Earth Observatory of Columbia University, said the impact of so much water could hasten an earthquake’s occurrence if geological conditions for a quake already existed. He said the best known example was a 1967 earthquake triggered by the Koyna Dam in a remote area of India, with a magnitude of about 6.5 and a death toll of about 180 people.
Mr. Seeber said that while the link between the Sichuan earthquake and the Zipingpu Dam was not yet proved, work by Christian Klose, a Columbia University researcher specializing in geophysical hazards, suggested the stress caused by the water’s weight might have hastened the quake by a few hundred years.
“It would have occurred anyway,” Mr. Seeber said. “But of course the people who were affected might think the timing is an important difference.” Mr. Klose estimated that the weight of the water in the Zipingpu reservoir amounted to 25 times the natural stress that tectonic movements exert in a year. The added pressure, he wrote in an abstract to an unpublished study, “resulted in the Beichaun fault coming close to failure.” Fifty stories tall and big enough to hold more than one billion cubic meters of water, the Zipingpu Dam astride the Minjiang River was billed as one of China’s biggest water control projects.
Officials said the $750 million project, part of a grand plan to develop regions in China’s south and west, would generate 760,000 kilowatts of electricity, irrigate more farmland, help control flooding and provide more water to industries and residents of nearby Chengdu, a city of more than 10 million.
Almost as soon as construction got under way in 2001, one expert, Li Youcai, voiced fears that officials were underplaying the risk of a major earthquake in the region, but government officials rejected his argument, according to an article published last year on China Dialogue, a Web site devoted to environmental news.
Officials allowed the reservoir to fill with water in late 2004. Fan Xiao, a chief engineer with the Sichuan Geology and Mineral Bureau, said that from late 2004 to late 2005, the data showed 730 minor earthquakes, with magnitudes of 3 or less.
When the major earthquake struck last May, it originated 3.4 miles from the reservoir. The rupture in the Earth’s crust stretched for 185 miles, initially moving in a direction that Mr. Klose said was consistent with the pressure from the water’s weight.
Mr. Fan, the chief engineer for the regional geology investigation team, told reporters soon afterward that he believed that the reservoir influenced the timing, magnitude and location of the earthquake.
“The main lesson is that in building these kinds of projects we need to give more consideration to scientific planning and not simply consider the electricity or water or the economic interests,” Mr. Fan said.
The debate reignited in December when two scientists with the China Earthquake Administration and three other researchers published a study in the Chinese journal Seismology and Geology. They concluded only that the weight of the reservoir’s water and diffusion of water from the reservoir below the Earth’s surface “clearly affected the local seismicity” over a period of nearly four years before the fault ruptured.
The Chinese researchers called for further study to see whether the reservoir helped trigger the earthquake. One of them, Du Fang, with the Sichuan Earthquake Administration, said Thursday that it was impossible to know whether the reservoir influenced the earthquake without more research. “The possibility exists,” she said.
Ms. Du said she and other scientists were free to research the issue fully. “We scientists are free to research the topic we proposed, as long as it is worth studying,” she said. “I don’t feel any restrictions on access to the data from the government.”
(Associated Press) Scientist says dam may have triggered China quake. Chi-chi Zhang. January 5, 2009.
Pressure from a dam, its reservoir's heavy waters weighing on geologic fault lines, may have helped trigger China's devastating earthquake last May, some scientists say, in a finding that suggests human activity played a role in the disaster. The magnitude-7.9 quake in Sichuan province was China's worst in a generation, causing 70,000 deaths and leaving 5 million homeless. Just 550 yards (meters) from the fault line and 3.5 miles (5.5 kilometers) from the epicenter stands the 511-foot-high (156-meter-high) Zipingpu dam, the area's largest. The quake cracked Zipingpu, forcing the reservoir to be drained.
Fan Xiao, a chief engineer at the Sichuan Geology and Mineral Bureau, said Wednesday that the immense weight of Zipingpu's waters — 315 million tons — likely affected the timing and magnitude of the quake. Though earthquakes are not rare in the area, one of such magnitude had not occurred for thousands of years, Fan said. "I'm not saying the earthquake would not have happened without the dam, but the presence of the massive Zipingpu dam may have changed the size or time of the quake, thus creating a more violent quake," Fan said in a telephone interview.
Seismologists recognize that large bodies of water may exert pressure on fault lines deep in the earth, leading to earthquakes. The pressure can push the sides of fault lines harder together, increasing friction, or cause the fault lines to slip apart. Scientists have recorded smaller earthquakes possibly caused by reservoirs. A magnitude-6.4 quake near India's Koyna dam killed at least 180 people in 1967 and is thought to have been induced by the reservoir.
Fan is among a number of experts who have voiced concerns in recent months about the likelihood that Zipingpu may have contributed to last year's quake. Their concerns were reported last month in Science magazine.
The Chinese government has portrayed the Sichuan quake as an unavoidable natural disaster, and it has promoted the building of large dams to meet the country's energy needs and reduce flooding. The Three Gorges Dam, the world's largest hydroelectric project, was built to end flooding in the Yangtze River and provide a clean energy alternative to coal, but has instead been plagued with problems, from resettlement to landslides.
Many scientists are not convinced that the Zipingpu dam caused the Sichuan quake, even if it may have been a factor. Lei Xinglin, a geophysicist at the government's China Earthquake Administration, said reservoirs increase seismic activity but will not cause an earthquake. He called for further investigation. "A reservoir in the region will have positive and negative effects on a potential earthquake, but it is ridiculous to say an earthquake was caused by the dam," Lei said. "In order to gain more knowledge, we still need to carefully research this topic rather than jumping to conclusions." Lei said a fall in the Zipingpu reservoir's waters between December 2007 and the time of the earthquake and the penetration of water into the fault line were "major factors" in the quake.
Roger Musson, a seismologist with the British Geological Survey, said at best Zipingpu may have accelerated the timing of the quake. "But the scale of the Wenchuan earthquake (185 miles, or 300 kilometers, of rupture) indicates that it was a true tectonic event which would have occurred with or without the Zipingpu dam," Musson said in an e-mail. "It is thus only a question as to whether stresses from the reservoir advanced the timing of the earthquake."
Also calling for further investigation is Christian Klose, a geophysical hazards research scientist from Columbia University in New York. An abstract of a paper he presented at the American Geophysical Union meeting in San Francisco in December said the added weight weakened the fault below Zipingpu.
Fan, the Chinese engineer, said he was so convinced of Zipingpu's potential dangers that he strongly opposed its construction in 2003, worried that a disaster would devastate the Min River valley below. He said he began pointing to the dam as a possible cause just a month after the quake.
Still, many large dams continue to be built. Fan said he has continued to write letters to government officials voicing concerns about dams being built on the Dadu and Jinsha rivers to the west and northwest of the quake zone.
(AlterNet) Why a Dam May Have Been the Cause of China's Deadly Earthquake Last Year. Peter Bosshard, AlterNet. February 6, 2009.
Last year's devastating Sichuan earthquake, which took at least 69,000 lives, may have been unleashed by the huge Zipingpu Dam. New scientific evidence links the impoundment of the Zipingpu reservoir to the activation of a fault line near the dam site. A thorough scientific assessment is needed before China builds more dams in earthquake-prone areas.
It is well established that large dams can trigger earthquakes through what is called reservoir–induced seismicity. There is evidence linking earth tremors and the raising and lowering of reservoirs for more than 70 dams. Reservoirs can both increase the frequency of earthquakes in areas of already high seismic activity and cause earthquakes to happen in areas previously thought to be seismically inactive.
Zipingpu is a 156-meter-high dam on the Min River, a tributary of the Yangtze. The project, which displaced 33,000 people, was completed with Japanese funding in 2006. Fan Xiao, a chief engineer with the Sichuan Geology and Mineral Bureau, had warned about Zipingpu's seismic risks since before the dam was completed. After the disaster, he explained that "Zipingpu has all conditions that provoke reservoir-induced earthquakes," and said that "we cannot rule out the possibility that building the Zipingpu Dam induced the earthquake because the epicenter is so close to the dam." (Fan's interview with the South Urban Daily, like other useful documents on the topic, has been translated by Three Gorges Probe.)
Geophysical hazards researcher Christian Klose of Columbia University's Lamont-Doherty Earth Observatory has found that the fault line that triggered the Sichuan quake had not been active for millions of years. Klose presented his research at a meeting of the American Geophysical Union in San Francisco in December. According to Klose, "the ensemble of geophysical observations suggests that the root cause of triggering the M7.9 Wenchuan earthquake may have stemmed from local and rapid mass changes on the surface." As a news article on Klose's findings in the January 16 issue of Science elaborates, "the added weight [of the Zipingpu reservoir] both eased the squeeze on the fault, weakening it, and increased the stress tending to rupture the fault. The effect was 25 times that of a year's worth of natural stress loading from tectonic motions. (…) When the fault did finally rupture, it moved just the way the reservoir loading had encouraged it to."
In a recent paper in the Chinese journal Geology and Seismology, Lei Xinglin, a geophysicist at the China Earthquake Administration in Beijing, and four colleagues produced further evidence for the seismic impacts of the Zipingpu Dam. According to the paper, "some clear correlations were verified between the local seismicity and stress change, thus we concluded that the impoundment of Zipingpu clearly affected the local seismicity and it is worthwhile to further study if the effect played a role in triggering the Wenchuan earthquake."
Now that you have read what they are saying in the west, how about reading what they are saying in China? Here I mean the people that the western media don't report on. For them, this is old news and a dead issue already. The first article is dated September 2008.
(XYS.org) Is the Zipingpu Dam related to the May 12th Wenchuan earthquake? By Li Min and Wang Yongxi. September 11, 2008.
...
The Chinese National Geographic magazine published Fan Xiao's article: <<The Wenchuan earthquake: The Secret Underground>> in issue number six of 2008. The article raised the question about whether the Zipingpu Dam triggered the Wenchuan earthquake. Together with the explanations and expositions by Fan Xiao at various venues and the hyping by Internet media, this issue has successfully seized public attention. But the truth should not require any hyping. Here are our specific responses.
Fan Xiao concluded that there are seven definitive indicators for an earthquake that is triggered by a dam. The list is summarized below:
(1) The dam has to be taller than 100 meters and the capacity has to more than 1 billion square meters;
(2) The dam area is seismically active;
(3) The dam area is located on a geological fault which has been recent movements;
(4) There is abnormal deep weight distribution;
(5) There are cracks deep in the rocks that make it porous to water;
(6) The dam area has seen earthquakes before;
(7) The dam area has hot springs.Fan Xiao claims that the more of these indicators are present, the greater likelihood that the dam may trigger an earthquake. The Zipingpu dam has the first six of these seven indicators.
Let us now analyze these seven so-called indicators.
(1) In the earlier portion of this article, we have shown that a tall dam is likely to see more earthquakes, but it is not the case that all tall dams trigger earthquakes. Therefore, a tall dam is not a distinguishing indicator.
(2) This is a necessary condition for dam-triggered earthquakes, but it is not a sufficient condition. There is a great deal of uncertainty involved.
(3) This works the same way as (2). The geological plate itself is not the reason for the quake; it is the activities along the fault.
(4) This is an indicator for determining the hidden structure, but it has no bearing on whether the water in the hidden faults can trigger an earthquake.
(5) The cracks in the rocks are usually not very deep and these cracks usually have nothing to do with the structure.
(6) Only earthquakes of moderate or stronger magnitude are caused by fault activities. Weak and mild earthquakes occur all over China. Even seismically inactive areas can have dam-triggered earthquakes.
(7) Hot springs indicate the depth of the water circulation under the earth. Whether a dam is there or not cannot change the depth of the water. Thus, the presence of hot springs is not a necessary condition for triggering earthquakes.
Clearly, Fan Xiao was only able to come up one of these indicators, namely the second indicator about seismic activities in the dam area.
Without requiring Fan Xiao to show us, we showed in 1990 that the Zipingpu dam meet the conditions for triggering earthquakes already. But this does not mean that any of the earthquakes that occurred after the Zipingpu dam began to collect water was not the continuation of natural earthquake events, and it does not say that the Zipingpu dam triggered the Wenchuan earthquake. Fan Xiao is misapplying the concept in order to mislead the public.
Fan Xiao wrote: "The Zipingpu dam began to store water on December 1, 2004. The water level began to rise from the initial 757 meters above sea level. By December 10, 2004, the water level had risen up to 761 meters; by the end of December, the water had write to 800 meters or so; by February 2005, the water level reached about 820 meters ..."
Fan Xiao also wrote: "Before the May 12 earthquake, the Sichuan Earthquake Administration had published the monitoring results about the Zupingpu dam area. The data period was between August 16, 2004 to September 30, 2005 when the water level was under 840 meters. A total of 735 magnitude 0.9 to 3.6 earthquakes were recorded."
Fan Xiao is citing the article written by Sichuan provincial Earthquake Administration Reservoir Earthquake Research Institute's Hu Xianping published in <<Sichuan Earthquake>> in June 2007. The article was titled <Natural earthquake activities before the Zipingpu dam began to store water>. Obviously, Hu Xianming was talking about 735 magnitude 0.9-3.6 earthquakes that occurred before the Zipingpu dam began to store water. But in order to mislead the public, Fan Xiao deliberately made up the fact that the Zipingpu dam began to store water on December 1, 2004. Even if Fan Xiao did not find out from the media reports that the Zipingpu dam only began to store water on October 1 (see, for example, QQ.com), 2005, he should at least have noticed that the article of Hu Xianming was entitled <Natural activities before the Zipingpu dam began to store water>.
Fan Xiao's article also said: "It is noteworthy that the earthquakes run along side of the north-south Longman Shan fault ... "
The article by Hu Xianming does not have any maps of the spatial distribution of the 735 magnitude 0.9-3.6 earthquakes. Instead, the only spatial map in that article was for magnitude 4.7+ earthquakes between February 11 of A.D. 638 and December 2005. This has absolutely nothing to do with earthquake activities after the Zipingpu dam began to store water. There is no indication as to how Fan Xiao could see that there is a circle of past earthquake activities with the dam at the center and a radius of 15 kilometers ....
I don't want to use the term "deliberate rumor mongering" to characterize a geologist. But the narrative from Fan Xiao is just "incredible." A professional expert should not be advancing the date at which the Zupingpu dam began to store water in order to mislead the public.
...
The Wenchuan earthquake of May 12 had no foreshocks. This is a typical earthquake-aftershocks event. In the four known cases of a reservoir triggering off earthquakes, they were all foreshocks-earthquake-aftershocks events. When the water storage caused mass loads and imbalances, a series of foreshocks will appear as the water permeates deeper into the structure. Of course, natural earthquakes may also be foreshocks-earthquake-aftershocks events as they are not triggered solely by dams. In any case, the Wenchuan earthquake is completely not consistent with the typical dam-triggered earthquake.
Until the Wenchuan earthquake occurred on May 12, the data collected by the Zipingpu earthquake monitoring station showed that there had not been any earthquakes stronger than magnitude 4. The magnitude 3.0-3.9 earthquakes had nothing to do with the Zipingpu dam. A comparison of magnitude >0.5 earthquakes before and after the dam began to store water did not show any obvious increase. There were no changes in weak earthquakes in Zipingpu or the surrounding areas.
Based upon the above, we have reason to believe that the May 12th Wenchuan earthquake is connected to the Zipingpu dam. Individual geologists and a small number of people with ulterior motives are spreading the idea that "the possibility that the Zipingpu dam triggered the Wenchuan earthquake cannot be excluded. They are deliberately misleading the public. Their various fabricated reasons are not supported by facts.
(XYS.org) Was the Zipingpu dam the manmade cause of the Sichuan earthquake? By Amsel. January 29, 2009.
In the January 16, 2009 issue of Science magazine, the weekly news section has an essay entitled: "A Human Trigger for the Great Quake of Sichuan? ". This essay presented the idea that "the Zipingpu dam might have triggered the Sichuan earthquake." People have to laugh after they finish it. For the purpose of attracting eyeballs, this top academic journal acted like the mainstream media by trying to be fair and balanced between two viewpoints. Instead of being able to come to a clear conclusion, it got all muddled up. It should be pointed out that this report is not a scientific paper and it is only a news report, with the biggest difference being that it has not been reviewed by experts ...
This viewpoints in this report about "the Zipingpu dam triggering the Wenchuan earthquake" came from two persons. One is the renowned anti-dam person Fan Xiao, who may have majored in geology but his knowledge about geology is actually terrible. He repeated the old refrain about how the water from the dam seeped into the earth. Fan Xiao's viewpoints have previously been rebutted by experts (see the translated XYS.org article before this one) and so there is no need to repeat here. The other character is Christian Klose, who graduated from the Swiss Federal Institute of Technology in 2003 and then worked a while at Columbia University. Science magazine is quoting the viewpoints that he delivered at the Fall 2008 Meeting of the American Geophysical Union.
The 2008 M7.9 Wenchuan earthquake - Result of Local and Abnormal Mass Imbalances?
Author: Klose, C D
Columbia University, School of Engineering and Applied Science, 351 Mudd Building, New York, NY 10027, United StatesAbstract: The May 12, 2008 M7.9 Wenchuan earthquake occurred along the Longmen Shan margin of the eastern Tibetan plateau in the Sichuan province of the People's Republic of China. A complex and NNW dipping reverse fault system including the Beichuan fault ruptured 250-300 km parallel to the Longmen Shan thrust belt. This region has been tectonically loaded for >10kyr. It has low deformation rates of less than 1.0±1.0 mm yr-resulting in no major seismic activity during the Quaternary period. Several geophysical observations suggest that this M7.9 earthquake was triggered by local and abnormal mass imbalances on the surface of the Earth's crust. These observations include (1) elastostatic response of the crust to the mass changes (2) slip distribution of the main rupture, and (3) aftershock distribution. Initially, approximately 2 years prior the nucleation of the mainshock, at least 320 million tonnes of water accumulated within the upper Min river valley. It enters the Chengdu plain of the Sichuan basin, a stable continental region (SCR). The water volume amplified the strain energy on the Earth's crust. Shear stresses increased by >1kPa on the Beichuan fault at the nucleation point in about 20km depth. Normal stresses decreased by <-4kPa and weakened the fault strength. Pore pressure increases might have additionally destabilized the fault locally due to pore pressure diffusion. This effect, however, might be minor in 20km depth, because of low lateral fracture connectivity and permeability between the area of water accumulation and the Beichuan fault. Overall, the stress alterations within a 120±70km2 large area resulted in the Beichuan fault coming closer to failure. Such an area ruptured would account for a M7.2±0.1 earthquake assuming only 10 MPa stress drop. Secondly, a reverse fault focal mechanism dominated, in particular, during the first 50 seconds of the main M7.9 rupture. The Beichuan fault slipped up to 7m upward peaking at shallow depth (<7km) (Nishimura and Yagi 2008). A third reason is that the aftershock distribution (M>3) along the ruptured fault zone pointed toward a very shallow seismicity in the uppermost part of crust. Data show that about 87% of the total seismic moment has been released in the upper third part of the crust (<10km), 1% in the middle third (10-20km), and 12% in the lower third (>20km). Such a bimodal depth distribution with an aseismic mid crust is typical for earthquakes in stable continental regions (Klose and Seeber 2007, SRL 78:554-562). Thus, high spatiotemporal correlatives can be observed at shallow depth between both the seismic moment release of the aftershocks and the rupture slip distribution of the mainshock. This indicates that Mohr-Coulomb failure stress states were much higher in the uppermost part of crust than near a possible nucleation point of the mainshock in 19km depth. In conclusion, the ensemble of geophysical observations suggests that the root cause of triggering the M7.9 Wenchuan earthquake may have stemmed from local and rapid mass changes on the surface
First of all, Klose does not not have the ability to study the relationship between the "Zipingpu dam and the Wenchuan earthquake." His conference synopsis mentioned that the Longmen Shan area is shifting at the rate of about one millimeter per year and that there has been no major earthquake activities since the Quaternary period. This means that no only does this geology Ph.D. lack knowledge about the local geological conditions (the Longmen Shan has been squeezed during the Quaternary period between the Tibet-Qinghai Plateau and the Yangzi depression and therefore continuous earthquake activities are inevitable). He even lacks commonsense knowledge about earthquake zones (how can a place where a magnitude 8.0 earthquake just occurred have no earthquakes since the fourth century?). For the past few centuries, the Longmen Shan fault has seen multiple magnitude 6+ earthquakes. The geological evidence also suggested that there was an earthquake even bigger than the one at Wenchuan occurring more than 3,000 years ago.
While the above error seems unbelievable, it gets worse because this was not his first mistake. His research direction seems to be "the relationship between human activities and earthquakes" and he has two case studies as evidence. Apart from the Wenchuan earthquake, he cites the 1985 magnitude 5.0 earthquake in southeastern Australia. He thinks that earthquake was caused by coal mining over the past 200 years there. His paper was challenged by Australian geology research scientists. In that article, Klose mentioned that "there had never been any earthquakes there for the past ten thousand years" and that was the basis of his mathematical model. But in reality, many magnitude 5+ earthquakes have been recorded there since the Europeans came to that area. Given Klose's lack of knowledge of geology and his indifference to the historical record, it is a miracle that he got into two famous universities in Europe and the United States and can publish in authoritative journals.
Secondly, Klose calculated the change in stress in the underground faults to explain the triggering effect. Even if people don't doubt the correctness of his model and software, they won't believe that he has enough data to conduct this kind of mathematical modeling. An accurate model requires knowledge of the geometric shape of the underground fault, the thickness of the rocks and their physical characteristics, the underground temperature and pressure and other data. These data can only be obtained through large numbers of deep drilling into the earth in order to take measurements. Such data are not available even to the local research scientists. Nevertheless, Klose was able to come up with a minute change in the underground stress through his model. This is no different from just making stuff up.
Thirdly, Klose's three indicators have not been accepted by the public. The public accepts that dams can trigger small earthquake, and this is mentioned in the Science magazine article. The Wenchuan earthquake is not a small earthquake and therefore it is not triggered by the Zipingpu dam. Thus, Klose was far from able to convince the conference participants about his views. Also, the Wenchuan earthquake had a rupture that was as long as 200 kilometers. There is no way to use his other two indicators to explain the distribution of the earthquake and its aftershocks.
Finally, just like Fan Xiao, Dr. Klose does not have an impressive academic background. He took a long time to get his degree and his publication record is not good. Although he claims to work at Columbia University, he cannot be located by searching the university website. The web page that he left behind at Columbia University links directly to his personal page www.cdklose.com. This page lists his interviews and conference papers, but it does not show if he has a research team or he receives grants. Among his research programs, the top entry is about whether the Wenchuan earthquake could have been triggered by changes of the weight put up the earth surface. We can only hope that no Chinese organization will be deceived by him.
The report in Science magazine interviewed a person with a deficient academic background for the purpose of creating a hot topic. This is sub-par. What will this article tell the Chinese readers? It is unlikely to be anything about how the Zipingpu dam might have triggered the Wenchuan earthquake. Rather, it is to remind people that even Science magazine can go for sensationalism, and that even famous universities such as Columbia University and the Swiss Federal Institute of Technology can sometimes produce lousy scholars ...
[Addendum: This Science report was posted on January 17 at XYX.org for people to read. At the time, I thought that the Zipingpu dam had already received detailed coverage by enough people so that the media should have no interest or possibility of hyping a story. Then I found out that essay was translated by the people over Yeeyan and subsequently picked up the stupid liberal writer Ran Yunfei (his anti-intellectualism is even more hopeless than Lian Yue) for his news commentary. This was then posted over at the Des-sci.org where the editor posted it on the front page. Ran Yunfei did not bother to read the translated article carefully and just glanced at some of the comments at Yeeyan after which he declared: "Unless the Zipingpu dam is completely removed, it will be a sword hanging over the heads of the people of Sichuan in the surrounding area ready to fall at any moment." Where does this come about? Even if you believe that the dam triggered an earthquake, how might the same dam trigger two earthquakes? But with the influence of Ran Yunfei among the environmental protection groups and the angry liberal youth, this essay was hyped up. That is the reason why I wrote this article.]
(Xinhua) "God's damnation" or China's dam - scientific debate on reservoir-quake link. By Wang Cong. February 20, 2009.
Should we blame a reservoir close to the epicenter for giving a deadly boost to the 8.0-magnitude earthquake, which hit southwest China's Sichuan Province on May 12, or was the quake merely the result of nature's wrath? International scientists are heatedly debating the possible link between the quake and the Zipingpu Reservoir, 5.5 kilometers from the quake's epicenter in the southeast part of Wenchuan County. The country's worst natural disaster in three decades, the earthquake claimed more than 69,000 lives and left five million people homeless.
Some Chinese and American scientists argued that the 156-meter-high Zipingpu Dam was evidence of another case of reservoir-induced seismic activity (RIS), while other scientists challenged the claim.
Lei Xinglin, a geophysicist at the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan, said preliminary research showed the filling and releasing of water in the Zipingpu reservoir from the end of 2007 to May 2008 "affected" the earthquake activities in that area. "We found the number of quakes increased during the reservoir's filling period, ... and the epicenters of quakes clustered in the southwest and southeast areas around the reservoir during the water releasing period," Lei and his co-workers wrote in a paper in the Chinese geosciences journal "Seismology and Geology" last December.
However, a member of the Chinese Academy of Sciences (CAS) who refused to be named said the Wenchuan tremor did not demonstrate the features of a reservoir-triggered quake. "A RIS has a unique vertical fault movement, but what happened during the Wenchuan earthquake was quite the opposite," the CAS member said.
Ji Shaocheng, a professor of Geophysics and Geology at the Ecole Polytechnique de Montreal, Quebec, Canada, also insisted that the Zipingpu Dam and the Wenchuan earthquake were not related. "The huge scale of the Wenchuan earthquake indicates unambiguously that it was a true tectonic event caused by eastward extrusion of the Tibetan plateau against the Sichuan Basin", Prof. Ji told Xinhua. Although the water piled behind the dam weighed more than 320 million tonnes, Ji said. "But since the water body covers a vast area, the stress it exerted on the riverbed is similar to that of a 50 or 60-storey building. Such stress was far from enough to cause the earthquake's violent rupture with a length of 280 km and a depth of 20-25 km within the crust, he said. "It's like scratching your foot while wearing a dozen boots," he said.
Like most reservoirs, Zipingpu was built near a fall of the Minjiang River, for power generation. It also happened to be an earthquake-active area. It began to be filled in December 2004, and can hold 1.1 billion cubic meters of water.
The reservoir's dam height, storage capacity, and location on a fault satisfied at least three main conditions for a RIS, said Fan Xiao, chief engineer for regional geological surveys at the Sichuan Bureau of Geological Exploration and Exploitation of Mineral Resources. "Statistics showed a reservoir with a dam height of over 100 meters and a total storage capacity of more than 500 million cubic meters has a 34 percent chance for causing RIS," Fan said. He did not say where the statistics came from.
As a long-time anti-dam advocator, Fan had advised against the building of Zipingpu for many years. "Lei's paper further convinced me the Zipingpu Dam and the Wenchuan earthquake were closely connected," Fan told Xinhua in a telephone interview. Fan Xiao even went as far as suggesting that a dam the size similar to Zipingpu would not only induce an earthquake, but also escalate the power of a potential earthquake. "There are four known RIS cases above 6.0-Magnitude around the world, including one in Xinfengjiang of China and another three in Zambia, Greece and India. All four were far more powerful than quakes that had been previously recorded in the regions," Fan said to Xinhua.
Nonetheless, Ji said the reservoir could not result in a 8.0-magnitude earthquake, unless it was filled with dynamite instead of water. He added that an 8.0-magnitude quake is close to 1,000 times more powerful than a magnitude-6.0 one.
The American journal Science published a news story on the "human trigger" for the Wenchuan Earthquake. It quoted Christian Klose, a Columbia University public hazards researcher, by saying the "several hundred million tonnes of water piled behind dams" both eased "the squeeze on the fault, weakening it, and increased the stress tending to rupture the fault." Klose did not mention any specific dam, but he said the effect of the stress of dam water was "25 times that of a year's worth of natural stress loading from tectonic motions." "When the fault did finally rupture, it moved just the way the reservoir loading had encouraged it to," he said. He concluded in a non-refereed abstract at the Fall Conference of the American Geophysical Union last month "the root cause of triggering the Wenchuan earthquake may have stemmed from local and rapid mass changes on the surface."
An email posted on Ji's blog (http://www.sciencenet.cn/u/Majorite/) from Zhou Hua-wei, a geophysics professor at the Texas Tech University, also said Klose's abstract was "not very convincing." Klose said in the abstract that Longmenshan region, where the earthquake rupture was, had no major seismic activity for more than one million years. "But the clear line of the Longmenshan Fault from a satellite photo in such a region of a high-precipitation climate already reveals its seismically active nature," Zhou wrote. "The average recurrence interval for M-8 earthquakes is in a range of 3,000-6,000 years in the Longmenshan region based on geological data", Ji Shaocheng said. "The conference abstract was not peer reviewed ... and is flawed in some facts," he said. "I think that Dr. Klose ought to present more detailed evidence in a journal paper, such as the "Journal of Geophysical Research", that will offer more room for a vigorous analysis," Zhou said.
Klose turned down an interview request from Xinhua, but said he would be open for statement after his paper is peer reviewed and accepted for publication.
Although Fan Xiao insisted that evidence linking the Zipingpu Dam and the Wenchuan earthquake has strengthened over the past months, he acknowledged that a firm conclusion was premature. "The clustered moderate earthquakes near the Zipingpu Dam before the Wenchuan earthquake Lei mentioned in his paper might also just be the pre-shocks of the May 12 earthquake," he admitted.
Ji said, "There are 6,678 reservoirs in the Sichuan province, and the Zipingpu is not the largest one."
For instance, the 240-meter-high Ertan Dam built in 1999 on the Yalongjiang River has a total storage capacity of 5.8 billion cubic meters; the 132-meter-high Baozhusi Dam has a total storage capacity of 2.6 billion cubic meters. "All those dams have never induced a destructive earthquake measuring above six degrees on the Richter scale, not to mention an 8.0-magnitude one like the Wenchuan quake," Ji said.
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