Science 5 March 2010: |
BEIJING—When experts suggested that the disastrous 2008 Wenchuan earthquake might have been triggered by the reservoir behind the Zipingpu Dam, establishment scientists in China remained largely silent (Science, 16 January 2009, p. 322). Now they've weighed in, ruling out reservoir triggering. But
many earth scientists don't buy their arguments.
No large quake had ruptured the Beichuan-Yinxiu fault in southwestern China's Sichuan Province in at least a millennium or two. Then engineers built Zipingpu Dam on the Min River just 500 meters from the fault and in late September 2005 began filling it with upward of 900 million tons of water. Two-and-a-half years later, the magnitude-7.9 Wenchuan earthquake got started 5 kilometers from the reservoir.
In the January issue of International Water Power and Dam Construction, three dam engineers at the China Institute of Water Resources and Hydropower Research here argue that the Zipingpu-Wenchuan situation was so unlike that of the four largest known reservoir-triggered earthquakes—all in the magnitude-6 range—that there could not have been a connection between reservoir and quake. The authors, led by structural engineer Chen Houqun, who has co-authored China's design code for building earthquake resistance into dams, contend that the timing was mere coincidence.
