Fluctuations in the amount of water behind China's Zipingpu Dam could have been the catalyst behind last year's deadly quake (above, the dam after the quake from the ground and via satellite on May 14, 2008), according to a recent study.
On its own, the four-year-old reservoir might not have created a very stressful situation, seismically speaking.
But the dam was built 1,650 feet (503 meters) from a geologic fault line, causing scientists to suspect the structure sped up and maybe even intensified the quake.
"In general terms, it has been verified that reservoir filling can trigger seismicity, due to the modification of stresses caused by the weight of the water," Emile Okal, a geophysics professor at Northwestern University, noted in an email.
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Photograph courtesy Imaginechina via AP Images; inset satellite photograph by GeoEye Satellite/AP