In Search of Cleaner Fuel

Peter Malin’s Seismology Group Uses Earthquake Technology to Explore Sources of Geothermal Energy p.4

That information proved useful as Mammoth Pacific settled on where to drill for a new hot water well, which has since been completed. “I found to my surprise that the place that we thought would be good to drill was actually the location of the first swarm in ’97,” Shalev said.

Back in Hawaii, Shalev is using the recently installed seismometer network to create a similar tomographic map for Puna Geothermal Venture’s new hot water well prospecting.

“We can produce a map that will show the amount of cracking in the ground,” he said. “We don’t have enough microearthquake data to produce this map yet, but I expect by March of this year we may have plenty of events to work with.”

The data have engaged the interest of and will be the dissertation material for volcano seismology doctoral student Kate Lewis Kenedi. “By recording so many microearthquakes, the bore hole seismometers give us a chance to locate fractures under Puna. We’ll help PGV find hot water, and we can work with the Hawaiian Volcano Observatory on volcano hazard mitigation.”

While the seismographs listen for new swarms of microearthquakes that are common in volcanic regions, the tiltmeters the Duke seismologists installed at some of those stations will also help the Hawaiian observatory monitor for movements of underground magma.

“Moving magma will push on adjacent rock, which can make the surface tilt,” Shalev explained.

Geothermal Heat Comes Naturally in Iceland
Onacha has been testing electrical and magnetic methods to track the location of hot underground water in Mammoth Lakes, his native Kenya and in another— this time frozen—nation where abundant volcanism has made geothermal energy a way of life.

In April 2006, Onacha chaired a conference at the Nicholas School on using those methods, plus microearthquakes and tomographic imaging, in Iceland. That three-day meeting brought U.S. and Icelandic scientists together.

“We are working in Iceland because the geology there is well known and less complicated than in other places,” Onacha said.

That country, where visitors can bask in open-air geothermally heated pools at night while watching displays of the aurora borealis, is actually a uniquely high-and-dry portion of Earth’s midocean ridge system, where volcanic lava creates new ocean crust.

Iceland’s rocks are of just one kind: basalt. That contrasts with the situation in Africa’s Rift Valley, where parts of the continent are slowly splitting apart amid a jumble of “all mixtures of rock,” he said.

“In Iceland, the houses are all heated by geothermal hot water, as is water in the showers,” he said. “So you don’t have to heat it up; you just turn on the tap. The water is always hot.”

Many of Iceland’s roads and sidewalks also are naturally steam-heated. And, of course the electric power grid also gets a large portion of its energy from the ground.

While Iceland's ventures in geothermal energies are well established, those in places like Basel are in their delicate early stages.

In the wake of the magnitude 3.4 earthquake in the Swiss city, a special counsel is now reviewing the safety of the project, Malin reports. “A go or no-go decision is likely to come in the next two to four months,” he said. “A great deal of European Union investment and hopes for geothermal power will rest on the outcome of this decision.”

Kahn will continue to work on the project “for as long as I have the funds and until, hopefully, he is able to finish his PhD,” Malin added.

Monte Basgall is senior science writer for Duke News and Communications.

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