Alaska Earthquake + Geothermal Drilling = Basel Redux?

A great article on the times today renews thoughts of the recent Alaska earthquake, and questions all the push for pipelines and domestic oil drilling through one of the most active volcanic and faultline prone areas in North America: [article]

Residents have been fighting for years with California power companies over the earthquakes, occasionally winning modest financial compensation. But the obscure nature of earthquakes always gives the companies an out, says Douglas Bartlett, who works in marketing at Bay Area Rapid Transit in San Francisco, and with his wife, Susan, owns a bungalow in town. “If they were creating tornadoes, they would be shut down immediately,” Mr. Bartlett said. “But because it’s under the ground, where you can’t see it, and somewhat conjectural, they keep doing it.”

It can remove the “conjectural” from the experience, though, when such things are tried closer to large population centers. The most interesting item in the article is the description by the leader of a previous geothermal project in Basel, Switzerland in 2006, when he realized that he had just set off a swarm of earthquakes, throwing Basel into panic:

By the time people were getting off work amid rain squalls in Basel on Dec. 8, 2006, Mr. Häring’s problems had already begun. His incision into the ground was setting off small earthquakes that people were starting to feel around the city.

Mr. Häring knew that by its very nature, the technique created earthquakes because it requires injecting water at great pressure down drilled holes to fracture the deep bedrock. The opening of each fracture is, literally, a tiny earthquake in which subterranean stresses rip apart a weak vein, crack or fault in the rock. The high-pressure water can be thought of loosely as a lubricant that makes it easier for those forces to slide the earth along the weak points, creating a web or network of fractures.

Mr. Häring planned to use that network as the ultimate teapot, circulating water through the fractures and hoping it emerged as steam. But what surprised him that afternoon was the intensity of the quakes because advocates of the method believe they can pull off a delicate balancing act, tearing the rock without creating larger earthquakes.

Then comes the, “whoops, did something just happen?” moment… after which, wait for it…

Alarmed, Mr. Häring and other company officials decided to release all pressure in the well to try to halt the fracturing. But as they stood a few miles from the drill site, giving the orders by speakerphone to workers atop the hole, a much bigger jolt shook the room.

“I think that was us,” said one stunned official. Analysis of seismic data proved him correct. The quake measured 3.4 — modest in some parts of the world. But triggered quakes tend to be shallower than natural ones, and residents generally describe them as a single, explosive bang or jolt — often out of proportion to the magnitude — rather than a rumble. Triggered quakes are also frequently accompanied by an “air shock,” a loud tearing or roaring noise. The noise “made me feel it was some sort of supersonic aircraft going overhead,” said Heinrich Schwendener, who, as president of Geopower Basel, the consortium that includes Geothermal Explorers and the utility companies, was standing next to the borehole.

… and the final punchline, a common historical effect of people playing with massive forces that technology allows us to leverage (like the economy, “we didnt know..”, or the atomic bomb, “The atomic bomb will never go off, and I speak as an expert in explosives.”, (Admiral William Leahy, on US Atomic Bomb Project, to President Truman in 1945)…. and surprised at the result:

“It took me maybe half a minute to realize, hey, this is not a supersonic plane, this is my well,” Mr. Schwendener said. By that time, much of the city was in an uproar. In the newsroom of the city’s main paper, Basler Zeitung, reporters dived under tables and desks, some refusing to move until a veteran editor barked at them to go get the story, said Philipp Loser, 28, a reporter there.