<p class="MsoNormal"><em>This story is part of a </em><a href="http://news.nationalgeographic.com/news/energy" target="_blank"><em>special series</em></a><em> that explores energy issues. For more, visit <a href="http://www.greatenergychallenge.com/" target="_blank">The Great Energy Challenge</a></em>.</p><p><strong>Annual U.S. nuclear generation: 798.7 billion kwh (kilowatt-hours)</strong></p><p>Japan’s Fukushima Daiichi crisis has raised questions around the world on the earthquake hazard in countries that rely heavily on nuclear power. As it turns out, the seismic threat varies widely in the top ten countries generating electricity by fission.</p><p>Although the United States has not built a new nuclear power station since the 1979 accident at Three Mile Island, it is far and away the world’s largest nuclear power producer. Its 104 reactors produce more electricity than all the nuclear plants in the next two nations—France and Japan—combined. But because U.S. electricity use is so prodigious, all those nuclear plants provide only 20 percent of the total.</p><p>Given the<a href="http://geohazards.usgs.gov/qfaults/map.php"> map of U.S. earthquake hazard</a>, it’s no surprise that California’s<a href="http://articles.latimes.com/2011/mar/21/business/la-fi-cal-nukes-20110321"> two nuclear power plants</a> are the ones that have raised the most<a href="http://boxer.senate.gov/en/issues-legislation/spotlight/nuclearsafety.cfm"> political concern</a> in the wake of Japan’s crisis. San Onofre, in San Clemente, and Diablo Canyon, in Avila Beach, are located right on the coast, near active faults.</p><p>Earthquake hazard in this area of the West, where the North American tectonic plate meets the Pacific plate, is about five times greater than the earthquake hazard in the eastern half of the United States, says seismologist Seth Stein, of Northwestern University’s Department of Earth and Planetary Sciences. He is author of the recent book,<a href="http://www.earth.northwestern.edu/people/seth/"> Disaster Deferred</a>, on how new science is changing views of earthquake hazards in the Midwestern United States. As the book explains, there is some seismic hazard in the central and eastern part of the country, where the vast majority of<a href="http://www.nrc.gov/info-finder/reactor/"> U.S. nuclear reactors</a> are located. Damaging earthquakes have occurred near Charleston, South Carolina; Boston, Massachusetts; and New Madrid, Missouri.</p><p>Long before the Fukushima crisis, U.S. energy and nuclear regulators and the<a href="http://www.epri.org/"> Electric Power Research Institute</a>—the industry nonprofit group—were working on a new seismic source characterization for the central and eastern United States. It’s expected to be completed later this year.</p><p>There are no nuclear plants in Alaska, the U.S.<a href="http://earthquake.usgs.gov/earthquakes/states/top_states.php"> state that has the most earthquakes</a>.</p><p>—Marianne Lavelle and Barbara Mulligan</p><p>(Related Photos: "<a href="http://news.nationalgeographic.com/news/2011/03/pictures/110315-nuclear-reactor-japan-tsunami-earthquake-world-photos-meltdown/">Japan Tsunami: 20 Indelible Images</a>")</p>

1. United States: Coastal Concern

This story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.

Annual U.S. nuclear generation: 798.7 billion kwh (kilowatt-hours)

Japan’s Fukushima Daiichi crisis has raised questions around the world on the earthquake hazard in countries that rely heavily on nuclear power. As it turns out, the seismic threat varies widely in the top ten countries generating electricity by fission.

Although the United States has not built a new nuclear power station since the 1979 accident at Three Mile Island, it is far and away the world’s largest nuclear power producer. Its 104 reactors produce more electricity than all the nuclear plants in the next two nations—France and Japan—combined. But because U.S. electricity use is so prodigious, all those nuclear plants provide only 20 percent of the total.

Given the map of U.S. earthquake hazard, it’s no surprise that California’s two nuclear power plants are the ones that have raised the most political concern in the wake of Japan’s crisis. San Onofre, in San Clemente, and Diablo Canyon, in Avila Beach, are located right on the coast, near active faults.

Earthquake hazard in this area of the West, where the North American tectonic plate meets the Pacific plate, is about five times greater than the earthquake hazard in the eastern half of the United States, says seismologist Seth Stein, of Northwestern University’s Department of Earth and Planetary Sciences. He is author of the recent book, Disaster Deferred, on how new science is changing views of earthquake hazards in the Midwestern United States. As the book explains, there is some seismic hazard in the central and eastern part of the country, where the vast majority of U.S. nuclear reactors are located. Damaging earthquakes have occurred near Charleston, South Carolina; Boston, Massachusetts; and New Madrid, Missouri.

Long before the Fukushima crisis, U.S. energy and nuclear regulators and the Electric Power Research Institute—the industry nonprofit group—were working on a new seismic source characterization for the central and eastern United States. It’s expected to be completed later this year.

There are no nuclear plants in Alaska, the U.S. state that has the most earthquakes.

—Marianne Lavelle and Barbara Mulligan

(Related Photos: "Japan Tsunami: 20 Indelible Images")

Emory Kristof, National Geographic

Pictures: Top Ten Nuclear Nations' Quake Hazard

Among the ten nations that produce the most nuclear power, Japan is not alone in facing earthquake hazard.

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