China's Dams

Three Gorges Dam triggers frequent seismic activities

(April 7, 2014) Chinese geologist and environmentalist Fan Xiao says the recent quakes that struck central China’s Hubei Province in Zigui county — “the first county of the Three Gorges Dam” due to its proximity to the project site — signal that the seismic threat posed by Three Gorges Dam is at its most critical stage now. Reservoir-induced seismicity (RIS) is most likely to occur within a few years, even a decade after initial filling of a dam reservoir to its highest level, due to the time it takes for reservoir water to penetrate deep into seismic faults and fissures before it triggers seismic activity. A 2010 study revealed seismic monitors around the Three Gorges Dam reservoir and in Hubei Province registered 3,429 earthquakes between June of 2003 (when inundation of the reservoir began) and December 31, 2009: a 30-fold increase in seismic frequency over the pre-dam period.

By New Tang Dynasty (NTD) Television on April 2, 2014

Zigui County of Hubei Province, so-called “The first county of the Three Gorges Dam,” has experienced two earthquakes of magnitude above 4.0 and hundreds of aftershocks in the past three days. Geoscientists believe these two earthquakes were clearly induced by the reservoirs of the Three Gorges Dam and are indications of future devastating earthquakes.

According to the China Earthquake Network Center, at 0:24 on March 30, a 4.7 earthquake took place in Zigui, 20 kilometers away from the Three Gorges Dam. This is the second earthquake after the 4.3 earthquake on the 27th in Zigui. As of March 30 at noon, 330 aftershocks have been triggered.

Zigui County is the county situated closest to the Three Gorges Dam area. Geoscientists analyze that Zigui earthquakes were induced by the reservoir. Hubei Earthquake Administration research director Wang Qiuliang told the Shanghai media that he believed these quakes were associated with the dam sitting on top of two major fault lines and the water pressure of the Dam. He also warned of the possibility of stronger quakes.

Fan Xiao, former chief engineer of Department of Geology and Mineral, Sichuan Province:

“Since 2003 when the Three Gorges Dam started to operate, the reservoir-induced seismic activity has been very obvious, and closely related to the changes of water level. The frequency and intensity of the seismic activity had been significantly increased before the construction.”

According to a 21st Century Business Herald report, Zigui County Records showed prior to 1986, there were a total of six directly perceived earthquakes in the past 1,000 years. Since the Three Gorges reservoir began operation in 2003, there have been 18 registered earthquakes in Zigui, with 15 of them right after the completion of the dam. Incomplete records showed another nearby county associated with the Three Gorges Dam, Badong County, has had more than 1,400 registered earthquakes below magnitude of 3.0. An earthquake of 5.1 took place last December.

Engineer Fan Xiao indicates that the reservoir-induced seismic activity is typically at its highest a few years after the routine high water level of reservoirs. The Three Gorges Dam is at that most critical stage now.

Fan Xiao: “Since the Three Gorges Dam took up water in 2003, including the water level at the high level of 2008, the region is at the most dangerous time, especially with the fault lines underneath the dam. Historically, earthquakes above magnitude of 6.0 have taken place around the reservoir area sitting on top of the fault lines. Therefore, the Zigui area is prone to reservoir-induced earthquakes of catastrophic nature.”

The Communist official media reported that the quakes did not cause any damage to the dam or any casualties. However, Fan Xiao warns of the implications of these two quakes.

Fan Xiao: “Even though the Three Gorges Dam was constructed with high seismic impact tolerance to earthquake magnitude of 6 to 7, however, dam area is typically prone to geological disasters. Any devastating earthquake could cause disastrous landslides and damage the Three Gorges Dam. Preventive measures ought to be strengthened.”

Prior to the launch of the Three Gorges project, numerous scientists and experts in water conservancy and geology had conducted feasibility studies. More than 100 experts, including Institute of Water Resources and Hydropower Research senior engineer Jin Yongtang, and Tsinghua University Professor Huang Wanli, had all strongly opposed the Three Gorges Project, saying it was bound to cause enormous irreparable damage. However, the Communist authorities turned a deaf ear to all objections.

Fan Xiao: “Feasibility studies in China, in particular for major large projects, are for political purposes. Once it’s politically determined, the studies are then conducted in service of the political goal. It is not part of a scientific and democratic process. To launch the projects, the negative or opposing suggestions and conclusions are often intentionally ignored, just to fulfill its political need and interest.”

The Three Gorges project has caused ecological damage, geological disasters, drought and sedimentation in the downstream of Yangtze River, and climate anomalies. These emerging disasters are what the experts such as Huang Wanli had warned of. More serious consequences are bound to happen.

Related

More earthquakes strike Three Gorges Dam region

Further Reading:

Are dams triggering China’s earthquakes?
Could dams be causing China’s earthquakes?
Aftershocks from Sichuan earthquake pose threat of secondary disasters
Sichuan earthquake may be aftershock of 2008 killer quake: Chinese geologist
Deadly earthquake in China may be aftershock of 2008 Wenchuan quake
On alert: RIS risk amid rash of earthquakes in China’s Sichuan-Yunnan region
Press Release: 80,000 deaths from 2008 Chinese earthquake was likely not an act of God, says new study
Mega-dams in China’s earthquake zones could have “disastrous consequences
Three Gorges Dam failing: Chinese dam increases risk of earthquakes
Hong Kong earthquake an aftershock triggered by Chinese dam 50 years ago

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