(October 28, 2009) Abstract: The devastating May 2008 Wenchuan earthquake (Mw 7.9) resulted from thrust of the Tibet Plateau on the Longmen Shan fault zone, a consequence of the Indo-Asian continental collision. Many have speculated on the role played by the Zipingpu Reservoir, impounded in 2005 near the epicenter, in triggering the earthquake. This study evaluates the stress changes in response to the impoundment of the Zipingpu Reservoir and assesses their impact on the Wenchuan earthquake. We show that the impoundment could have changed the Coulomb stress by −0.01 to 0.05 MPa at locations and depth consistent with reported hypocenter positions. This level of stress change has been shown to be significant in triggering earthquakes on critically stressed faults. Because the loading rate on the Longmen Shan fault is <0.005 MPa/yr, we thus suggest that the Zipingpu Reservoir potentially hastened the occurrence of the Wenchuan earthquake by tens to hundreds of years.

Shemin Ge, Mian Liu, Ning Lu, Jonathan W. Godt and Gang Luo, Geophysical Research Letters, October 28, 2009

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Further Reading:

Controversial Zipingpu dam may have caused China’s deadly earthquake, says Chinese geologist Fan Xiao

Scientists build case that Zipingpu dam triggered China’s devastating earthquake

Chinese geologist says Zipingpu dam reservoir may have triggered China’s deadly quake, calls for investigation

Integrated analysis of stress and regional seismicity by surface loading: a case study of the Zipingpu reservoir

Was China’s deadly earthquake man-made or an act of God?