17 December 2010

Storing carbon dioxide underground could trigger earthquakes, says Stanford geophysicist Mark Zoback

Stanford geophysicist Mark Zoback spoke Dec. 13 at the annual meeting of the American Geophysical Union in San Francisco's Moscone Center West. His talk was a be part of the session Land-Ocean-Atmospheric Processes: Implication to Natural Hazards and the Global Carbon Cycle I.

An attempt to slow global warming by pumping carbon dioxide underground – a proposal known as carbon sequestration – is likely to trigger earthquakes, according to Stanford geophysicist Mark Zoback.

While such earthquakes are unlikely to be big enough to injure people or damage property, they could still cause serious problems for the reservoirs containing the gas, as well as arouse public concern.

Many of the sites being considered for sequestration in the United States are in the interior of the country, far from major faults such as the San Andreas. But Zoback says these interior areas still have an abundance of faults, many poised in "a state of failure equilibrium." When carbon dioxide is pumped into a reservoir for sequestration, the fluid pressure in the reservoir will increase and some of those faults will fail, he said.

The damage would occur underground. Even an earthquake of modest size could potentially breach the seal of a reservoir, allowing carbon dioxide to permeate back to the surface. Although it is highly unlikely that the gas would pose a danger to people or livestock, it would render the reservoir useless.

"I am not against carbon dioxide sequestration by any means and it certainly has a role," Zoback said. "What I am asking people to consider is whether or not it should really be one of the key components of a strategy for reduction of greenhouse gas."

More details on the Fall Meeting of the American Geophysical Union is here: