Dams and Earthquakes

An article that should not be ignored

(May 27, 2009) An important article has been banned in China since 2003. It was even read by the Prime Minister who commented on it. Ultimately, the tragic May 12, 2008 earthquake proved its significance.

In 2003, Li Youcai, a retired senior engineer from the Sichuan Seismological Bureau, and CIO Shuheng, a senior engineer at the Sichuan Geological and Mineral Bureau, wrote an article entitled: “Discussion on Several Issues.” Their article argued that no hydro dams should be built in the Dujiangyan and Zipingpu area given the possibility of powerful earthquakes in the region.

As Li Youcai explained in his co-authored article, when construction of the Zipingpu dam project officially began in 2002, he accidentally saw a report by the Center for Seismic Analysis and Prediction of the China Seismological Bureau about the seismic risks associated with the Zipingpu dam. In that report, based on his own professional training, he found serious problems and flaws with its analysis.

The report concluded that “the maximum seismic intensity (SEE EDITOR’S NOTE 1) is likely to reach but will not exceed VII”. The reason being that historically there was no record of strong earthquakes in the vicinity of the dam site or in the surrounding 40 square kilometers, although there was a history of seven strong seismic events recorded in the peripheral region. Thus, based on a comprehensive analysis of multiple factors such as the crustal structure, the size of deep faults, the age of active faults and the impact of the seismic intensities, the report concluded that the site of the Zipingpu dam was geologically stable.

The two authors challenged this conclusion, based on their own studies, stating that because seismic activity with a magnitude of 7, and above, had occurred historically within the Zipingpu construction site and the surrounding 40 square kilometer area, the dam site was far from geologically stable. They felt that, in the event of an earthquake, the seismic intensity in the area could reach IX or even higher.

In February 2003, the two authors completed the first draft of their article. Mr. Li told the reporters from the Beijing-based Science Times, “In the very beginning, the departments concerned paid attention to our article and then submitted it to Premier Wen Jiabao. In March 2003, the Premier read it and commented immediately. Soon after, three experts were sent from Beijing to Chengdu (SEE EDITOR’S NOTE 2) and had a discussion with me.” “However,” Mr. Li continued, “the departments concerned, including the State Seismological Bureau and Sichuan Seismological Bureau, objected to our article, saying that I was wrong and they were right.” (SEE EDITOR’S NOTE 3)

Mr. Li kept all the materials on which these departments commented, reviewed them, and then revised his article. Despite this, both the State Seismological Bureau and Sichuan Seismological Bureau rejected his revised article too.

Since 2003, when they wrote their original article, Mr. Li and his co-author have revised it five times in an effort to improve and strengthen their arguments. Their latest update was made in March 2008. (SEE EDITOR’S NOTE 4) But no academic journals in China dared to publish their article. “The pressure (SEE EDITOR’S NOTE 5) has been huge,” Mr. Li told the Science Times.

“I kept updating and submitting the article and related materials to the higher authorities. Even in March 2008, I sent the latest material to the province and central governments by mail. In the latest one, I try to refute the arguments in the report and point out that they contain many lies and errors, as do their comments made on our article,” Mr. Li said to the Science Times.

The Science Times asked Mr. Li a couple of questions: why did the authorities or the departments concerned treat the article this way? Why did so many experts in the various departments refuse to have one more look at their own report and check the data concerned once again? Mr. Li replied, “I guess they were unwilling to accept our arguments because all their years of research would have been thrown out.”

As Mr. Li and his co-author pointed out in their article, there are several problems with the report by the State Seismological Bureau.

First, the report did a poor job studying the major faults in the dam site and surrounding area. “The report didn’t bother to mention two important fault belts, including the south-north Songpan-Wenchuan-Dujiangyan-Emei-Leibo, and east-west Nanchong-Guanghan-Dujiangyan, which both go through the Zipingpu dam site and surrounding area. The report also paid little attention to the well-known Longmenshan Fault, which is beneath the Zipingpu reservoir,” Mr. Li added.

Second, the report failed to look into the activities of deep, hidden faults beneath the Zipingpu dam site and surrounding area. It’s no wonder that an investigation of these hidden faults was not done, considering that the State Seismological Bureau report missed the two important fault belts (Songpan-Wenchuan-Dujiangyan-Emei-Leibo and Nanchong-Guanghan-Dujiangyan) too.”

Third, the study’s history of seismic activity and, in particular, the role of ancient buildings as records of the history of earthquakes in the region is problematic. “The report cited seven strong earthquakes within a range of about 300 km of the dam, but they only went back 100 to 200 years ago. Earlier data was not considered … The ancient buildings, in the dam site and surrounding area in particular, are an important witness to history, but the report said nothing about them at all, especially those which bore evidence related to historical seismic activity,” Mr. Li explained in his article.

After pointing out problems with the State Seismological Bureau’s report and doing an intensive study of the fault belts in the Zipingpu dam site and surrounding area, Mr. Li and his co-author concluded: “The Dujiangyan and Zipingpu area is a highly geologically complicated region, where three groups of fault belts meet and mingle with each other.” The tectonic activities have intensified in the recent decade in the region in general and in the Songpan-Wenchuan-Dujiangyan Fault Belt, in particular, the co-authors stated in their article.
Based on both discussions and analysis, Mr. Li and his co-author made the following “bold predictions.”

1. The dam site and surrounding area would be the central location for future powerful earthquakes, with a magnitude about 7.5.

2. The intensity of seismic activity in the dam site and surrounding area would be high. “From our point of view, the basic seismic intensity should be IX and even higher, rather than the VII level seismic intensity predicted by the State Seismological Bureau report, which is obviously too low. The Zipingpu dam would have difficulty withstanding earthquakes greater than magnitude 7, which would be disastrous and destructive for the dam.”

3. The dam site and surrounding area would become a disaster-prone region on completion of the Zipingpu dam, with the disasters including seismic activity causing mountain collapses, floods, catastrophic dam failure, and the ensuing mud-rock-flows, and possible damage to the downstream city and site of the ancient Dujiangyan water diversion system, and so forth.

Based on the above analysis, the article concluded:

First, the conclusion of the State Seismological Bureau report that “the maximum seismic intensity is likely to reach, but not exceed, VII in the dam site and surrounding area” should be discarded, replaced by a level IX or higher seismic intensity.

Second, the judgment that the Zipingpu dam site area is geologically stable is also incorrect; rather, the dam site area is basically unstable geologically, and there is a geologic history of earthquakes suggesting that future earthquakes as big as magnitude 7.5 could occur in the dam site and the surrounding area.

Finally, but not least importantly, the authors suggested that construction of the Zipingpu dam be stopped and that any portion already built be blasted for good. Failing this, they recommended that the original design be revised to withstand a seismic intensity of IX or higher, not the VII it was originally designed for. Moreover, they argued, the State Council should invite experts from the Chinese Academy of Sciences, Ministry of Water Resources, and Ministry of Geology and Mineral Resources and other ministries to meet, reexamine, and consider ways to retrofit the dam to withstand a higher seismic intensity earthquake.

With regard to the above issues arising from the article, the reporters from the Science Times tried to interview experts and officials at the departments involved, but these officials refused to make comments, saying that they knew nothing about it.

“There are more serious problems and many unanswered questions about the Zipingpu dam project, and our analysis and opinions are only based on our own study. We have attempted to answer the questions, but further study is needed,” Mr. Li told the Science Times.

EDITOR’S NOTES:

1. Of an earthquake in the Zipingpu area. The scales of seismic intensity offer a subjective way of measuring and rating the effects or severity of an earthquake. Intensity ratings are expressed as Roman numerals between I at the low end and XII at the high end. Seismic intensity is determined by effects felt by people, human structures and the natural environment. See here. The Richter scale, on the other hand, provides an objective way of measuring and comparing the size of earthquakes using a mathematical device. See the United States Geological Survey (USGS).

2. The capital of Sichuan Province and where the authors were based.

3. Referring to the report by the Center for Seismic Analysis and Prediction of the China Seismological Bureau.

4. Just two months before the May 12, 2008 earthquake.

5. From the departments concerned including the two bureaus mentioned above.

Han Yong and Wang Jing, The Science Times, May 27, 2009

Originally published in the Science Times on May 11, 2009

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