An open disucssion about the possible man-made cause for the earthquake may shed light on predicting future earthquake given China’s energy development trajectory. Here is a discussion about the link between dam and earthquake in China from EastSouthWestNorth:

The several hundred million tons of water piled behind the Zipingpu Dam put just the wrong stresses on the adjacent Beichuan fault, geophysical hazards researcher Christian Klose of Columbia University said at a session last month at the Fall Meeting of the American Geophysical Union in San Francisco, California. In his talk, Klose coyly explained–without ever mentioning a dam–how the added water changed the stresses on the fault. According to his calculations, the added weight both eased the squeeze on the fault, weakening it, and increased the stress tending to rupture the fault. The effect was 25 times that of a year’s worth of natural stress loading from tectonic motions, Klose said. When the fault did finally rupture, it moved just the way the reservoir loading had encouraged it to, he noted.

 

Klose’s listeners were intrigued but far from convinced. They wanted to hear more details about changing water levels and local, lower-level seismicity. Fan, who was not at the meeting, provides some of those details, all of which favor a link between the Zipingpu Reservoir and the earthquake. Judging by the history of known reservoir-triggered quakes, the rapid filling of Zipingpu as well as its considerable depth would have favored triggering, he says. The delay between filling and the great quake would have given time for reservoir water to penetrate deep into the crust, where it can weaken a fault. And the greatest danger of triggering comes not at the time of maximum filling, he argues, but when the water level is falling. "As we now know, a week before the May 12 earthquake, the water level fell more rapidly than ever before," says Fan.

 

A paper in last month’s issue of the Chinese journal Geology and Seismology arrives at a similar conclusion. Zipingpu’s impoundment "clearly affected local seismicity," says lead author Lei Xinglin, a geophysicist at the China Earthquake Administration in Beijing and the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan. Lei emphasizes that a firm conclusion is premature, but he sees penetration of reservoir water into the fault and the reservoir decline between December 2007 and May 2008 as "major factors associated with the nucleation of the great Sichuan earthquake."

 

Fan also does not see the Zipingpu-Wenchuan connection as proven yet, but he’s seen enough to urge caution. "We should readjust our existing plans and take a more cautious attitude when planning projects," he says. "But I am pessimistic that many of these large-scale constructions will be canceled, because of the strong economic interests that benefit hydropower developers and local governments."

 

Building a stronger case for restraint, researchers in and out of China say, will require access to even more detailed data. "Time-variation evidence for seismicity of small earthquakes near and surrounding the reservoir, as well as for the water levels and loading of the reservoir, are needed," says geophysicist Wen Xue-ze of the Sichuan Seismological Bureau in Chengdu. Fan believes that researchers in the Chinese Academy of Sciences have preliminary results from such studies, "but they are reluctant to share them."