Could geothermal energy projects cause earthquakes?

Visitors soothe themselves in a geothermal spa in Grindavik, Iceland while, in the distance, a power plant transforms the rising steam into electrical power.
Visitors soothe themselves in a geothermal spa in Grindavik, Iceland while, in the distance, a power plant transforms the rising steam into electrical power.
Peter Adams/Digital Vision/Getty Images

"Just add water." To some, these are the sweetest words in the English language. Why just think of the wonders those simple instructions bring to our lives: Kool-Aid, Sea-Monkeys, Chia Pets, Alka-Seltzer and all the cooing mogwais (from the movie "Gremlins," not the Scottish post-rock band) you can possibly stand.

With the possible exception of Alka-Seltzer, it's hard to argue any of these things vastly improve the quality of human life. But what if we could just add water to something and, say, solve the planet's energy crisis? That's essentially the idea behind artificial geothermal energy. Think back to your grade-school cutaways of the Earth and you might remember that the planet is filled with super-heated layers of mantle and core. Dig down just a couple of miles and bedrock temperatures can reach as much as twice the boiling point of water. Go deeper and things heat up even more.

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Under natural conditions, water regularly seeps down to these hot spots, expands into steam and then rises back to the surface in the form of geysers and hot springs. Sightseers often find these occurrences breathtaking while fatigued people and monkeys can find them soothing. To energy gurus, however, they are founts of gold.

Power plants burn mountains of coal and even split the atom just to generate the heat required to produce steam, which is then used to drive electricity-generating turbines. Since the Earth is just giving geothermal energy away, we've learned to harness this clean alternative to fossil fuels.

Geothermal power simply involves taking this naturally occurring steam and redirecting it through a turbine or two. This technology eventually led to the development of engineered or enhanced geothermal systems (EGSs). After all, we know there's hot rock down there, and in some corners of the world we don't even have to dig that far to get to it. Why not just drill to the hot rocks, pump some water down the well and reap the steamy rewards?

Sold on the idea? Well, there's one possible side effect to all this tinkering with the natural order of things: catastrophic earthquakes.

Spring to the next page to find out what the deal is.

Artificial Geothermal Energy and Earthquakes

Artificial geothermal energy isn't alone. According to a Columbia University study, the most damaging quake in Australian history was due to changes in tectonic forces brought on by 200 years of coal mining. The 1989 quake caused $3.5 billion in damages.
Artificial geothermal energy isn't alone. According to a Columbia University study, the most damaging quake in Australian history was due to changes in tectonic forces brought on by 200 years of coal mining. The 1989 quake caused $3.5 billion in damages.
AP Photo/Visar Kryeziu

You don't have to go out of your way to find doomsayers when it comes to methods of supplying the world's electrical power. Carbon emissions might melt the icecaps and drown whole cities. Nuclear power might turn the surrounding area into a radiated no-man's land. Biofuels could starve developing countries and further ravage the rainforests.

The severity of these threats really depends on whom you ask, but that's where the risks of artificial geothermal energy differ from everything else. Enhanced geothermal systems (EGSs) actually have produced earthquakes. On Dec. 8, 2006, Geothermal Explorers International managed to set off an earthquake in Basel, Switzerland, damaging buildings and terrifying the population. And while it only measured a 3.4 on the Richter scale, the quake was followed by 60 aftershocks in the weeks to follow.

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Earthquakes typically occur around unstable areas such as volcanoes, fault lines and geothermal regions. So, any area ripe for enhanced geothermal tinkering is already prone to get the shakes. On top of that, pumping water down to subteranian regions of heated bedrock causes the rock to expand and contract, fracturing the rock. As such, seismic activity isn't just a side effect of the process, it's a part of the process. The deeper the shaft, the greater the chance that increased levels of seismic activity could reach nearby fault lines, generating an even more powerful earthquake.

Geothermal Explorers International and the Swiss government both attributed the earthquake in Basel to artificial geothermal energy, so operations there ceased. Still, that's not stopping the U.S.-based AltaRock Energy from trying the same thing in California. After all, there's a great deal of money to be made in alternative energy -- that is if you can avoid crippling litigation and seismic catastrophe.

Explore the links on the next page to learn even more about geothermal energy and the inner workings of the planet.

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Sources

  • Glanz, James. "Deep in Bedrock, Clean Energy and Quake Fears." New York Times. June 23, 2009. (July 30, 2009)http://www.nytimes.com/2009/06/24/business/energy-environment/24geotherm.html?em
  • Lepisto, Christine. "Geothermal Power Plant Triggers Earthquake in Switzerland." TreeHugger.com. Jan. 21, 2007. (July 30, 2009)http://www.treehugger.com/files/2007/01/geothermal_powe.php
  • Lovett, Richard A. "Coal Mining Causing Earthquakes, Study Says." National Geographic News. Jan. 3, 2007. (July 30, 2009)http://news.nationalgeographic.com/news/2007/01/070103-mine-quake.html
  • Nasr, Susan L. "How Geothermal Energy Works." HowStuffWorks.com. May 18, 2009. (July 30, 2009)https://science.howstuffworks.com/earth/green-technology/energy-production/artificial-geothermal-energy.htm