Does tapping geothermal energy cause earthquakes?

I forgot to mention in my posts last week about visiting the Salton Sea that the biggest things on the horizon there are geothermal energy plants. When I first saw one, whizzing by at 60 mph in the 5:30 a.m. half-light, I thought, "It looks like a miniature refinery."

In the light of day they look a bit different. My first brush with geothermal came close in time to what looks like a light-of-day-type revelation coming out of Germany regarding geothermal energy. There, scientists say geothermal appears to have caused an earthquake last month.

Now, geothermal has lots of potential to help slow down the rate of global warming, as my erstwhile colleague Tom Paulson has written about.

But a piece by the New York Times' Nicholas Kulish and James Glanz highlights what happened in the little town of Landau In Der Pfalz last month:

The police logged as many as 200 calls after the quake, which struck shortly after 2 p.m. on Aug. 15. Stefanie Schuster was at the local supermarket when she heard a loud bang. She said she wavered unsteadily on her feet “like when you feel dizzy.”

It turns out that AltaRock Energy, the firm running the German plant in question, is also proposing one in California. And, not far from my brother's house in northern California, small geothermal-related earthquakes already have been reported.

And it also seems that at least one other geothermal plant, in Switzerland, had previously caused an earthquake.

So, in Dateline Earth's never-ending quest for the 100 one-percent solutions to global warming, we feel compelled to ask readers: How much should we be pursuing geothermal? Discuss.

-- Robert McClure