June 4, 2008

Wired magazine lists building a dam as the one of the top five ways to cause a man-made earthquake, linking to recent Three Gorges Probe article “China’s deadly earthquake: Was the Three Gorges reservoir a trigger?”

Wired writer Alexis Madrigal writes: “Water is heavier than
air, so when the valley behind a dam is filled, the crust underneath
the water experiences a massive change in stress load. For example, the
Hoover Dam area experienced hundreds of quakes as Lake Mead filled.
University of Alaska seismologist Larry Gedney explained, “Since [the
dam] reached its peak of 475 feet in 1939, the level of seismicity has
fluctuated in direct response to water level. None of the shocks has
been particularly damaging — the largest was about magnitude 5 — but
the area had no record of being seismically active.” Other examples of dam-caused quakes abound
and Klose’s research indicates that about one-third of human-caused
earthquakes came from reservoir construction. This science has raised
fears that the recent earthquake in China was caused by the filling of the Three Gorges Dam reservoir, although no conclusive evidence has been presented.”

“In the past, people never thought that human activity could have such a big impact, but it can,” said Christian Klose, a geohazards researcher at Columbia’s Lamont-Doherty Earth Observatory.”