(February 11, 2009) Probe International has called for an investigation into the role of the Three Gorges dam in the Chinese earthquake. Incorrect reporting had Probe claiming that the Three Gorges dam was responsible for the devastating earthquake
Letter to Editor
222 Sutter Street Suite 600
San Francisco, California 94108
In her February 5 blog posting, Elizabeth Gettleman said my organization had blamed the Three Gorges dam for causing the devastating Sichuan earthquake last year. She is mistaken. I did, however, recommend an investigation into the possible role of the Three Gorges Dam.
There is no reason to dismiss the possibility that the Three Gorges Dam could have been a factor in the Sichuan earthquake. It is well established that large dams cause reservoir-induced seismicity. The Three Gorges dam — the world’s largest — is thought to have induced 1,000 micro-earthquakes, 822 tremors, and a magnitude 4.7 earthquake 120 miles from the reservoir.
The Three Gorges reservoir sits on two major faults (which can alter a fault line’s mechanical state and cause fault activity to intensify and induce earthquakes). This reservoir stretches upstream to Chongqing, some 200 miles from the epicenter of the May 12 quake. If any dam deserves a thorough, independent scientific investigation of its potential seismic consequences, Three Gorges is it.
There was a Canadian feasibility study, commissioned by the Chinese government to help it raise funds to build the dam. This study underestimated the risk of reservoir-induced-seismicity. [Read our book critiquing it]
Ms. Gettleman absolves the Three Gorges Dam as a suspect, in part because Three Gorges is thought to be too distant from the quake’s epicenter, in part because scientists now suggest that the Zipingpu dam, just a few miles from the epicenter, might have induced it. We too suggest this — it was Probe International’s translation, in fact, that broke the Zipingpu story in the English-speaking world.
At the same time, we know that the science on reservoir-induced seismicity is far from complete, and that no one can with confidence rule out a role for the Three Gorges Dam. In the interest of sound science, let’s do the research before we come to our conclusions.
Probe International, February 11, 2009