Vincent Yu/AP
Earthquake survivors climb up a rocky embankment after arriving on a boat from areas
inaccessible by road at the Zipingpu Dam.

Deadly China Earthquake May Have Been Man-Made, Like Many Others

February 05, 2009 01:00 PM
by Josh Katz
Some scientists claim that a man-made dam triggered the devastating Sichuan earthquake of May 2008. Dams have been responsible for earthquakes in the past.

Scientists Say Dam Ignited Chinese Quake

Some scientists say the 7.9 magnitude earthquake that struck Sichuan last May and killed about 700,000 people and displaced more than 5 million may have been sparked by the large 511-foot-high Zipingpu dam located miles from the epicenter. The dam is only 550 yards from the fault line, and scientists say 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,” according to the Daily Telegraph.

Fan Xiao, the head engineer of the Sichuan Geology and Mineral Bureau in Chengdu, said it was “very likely” that the building of the dam precipitated the earthquake, noting, “This earthquake was very unusual for this area.”

The Chinese government has consistently rejected speculation that the dam led to the quake and has prevented “access to seismological and geological data” on the matter. The government has promoted the development of dams both for economic reasons and to reduce flooding. Fan says the government had ignored former warnings about the Zipingpu dam’s potential for destruction.

But Lei Xinglin, of the China Earthquake Administration, said, “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.” According to Lei, “In order to gain more knowledge, we still need to carefully research this topic rather than jumping to conclusions,” The Associated Press reports.

Also, Roger Musson, a seismologist with the British Geological Survey, said “the scale of the Wenchuan earthquake indicates that it was a true tectonic event which would have occurred with or without the Zipingpu dam,” and, “It is thus only a question as to whether stresses from the reservoir advanced the timing of the earthquake.”

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Background: China’s warnings, and man-made earthquakes

In March 2008, just before the China earthquake, Scientific American reported on warnings that the Chinese government ignored about the dangers of the Three Gorges Dam, the largest in the world. The article said that the government was warned for more than three decades. Engineers in China hold dams responsible for at least 19 earthquakes over the last five decades, including a 6.1 magnitude quake in 1962, according to Scientific American.

Many scientists say such reservoir-induced seismicity was the reason for the quakes at California’s Oroville Dam. The “largest earthen dam in the U.S.,” Oroville Dam was built on an active fault line in the 1950s. In the 1970s, “the area experienced an unusual series of earthquakes,” according to Scientific American, and “U.S. Geological Survey seismologists subsequently found a strong link between the quakes and the refilling of the reservoir.”

Man-made earthquakes are not uncommon. Christian Klose, a geohazards researcher at Columbia’s Lamont-Doherty Earth Observatory, told Wired in a June 2008 article that approximately 25 percent of the seismic events recorded in Britain were caused by man, although most man-made quakes are very small, registering intensities below 4.0. Klose estimated that “about one-third of human-caused earthquakes came from reservoir construction,” according to Wired magazine.

When Lake Mead was being filled, hundreds of small earthquakes occurred at the area around the Hoover Dam. University of Alaska seismologist Larry Gedney said, “Since [the dam] reached its peak of 475 feet in 1939, the level of seismicity has fluctuated in direct response to water level,” and the “area had no record of being seismically active.”

Wired also lists four possible man-made causes of earthquake besides dams. Injecting liquid into the ground, or drilling all the gas from a geyser can spur quakes. In regard to the latter, “Three of the largest human-caused quakes occurred near a natural-gas field in Uzbekistan, the Gazli. The combination of liquid extraction and injection changed the tectonic action in the field,” Wired writes. Some also believe that a quake could stem from the construction of a very large building.

Related Topic: The government’s response to the China quake

In the aftermath of the China quake, the international community praised the Chinese response to the disaster. Relief efforts quickly sprang into action, and Chinese Premier Wen Jiabao immediately traveled to the affected area, surveying the damage and attempting to console the population.

China’s management of the crisis differed from the way the country has dealt with prior calamities. The government was considerably more open in its dissemination of information about the Sichuan earthquake than it was during the SARS outbreak of 2003, the snowstorms in January 2008, and the Tibetan protests, according to Bloomberg.

Some analysts said China’s response presented a stark contrast with Myanmar’s handling of Cyclone Nargis. The ruling junta in Myanmar was accused of shunning international help, hampering the spread of information and withholding aid from its people.

Although Beijing’s leadership was applauded for its response to the earthquake, some criticized China for not taking strict preventative measures. The country tightened building codes after the deadly 1976 Tangshan earthquake, but those laws have been followed much more closely in urban areas than in the rural ones that suffered the most from the recent earthquake. One woman wrote in a chatroom, “Why did so many schools collapse but all the government buildings were fine? It’s outrageous!” the Los Angeles Times reported.

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