The March 11, 2011 earthquake and tsunami caused massive destruction in Japan. Six nuclear reactors at the Fukushima Dai'ichi power plant became a significant cause for concern in the aftermath as the plant lost power and reactor cores started melting down. Both the earthquake and tsunami were much larger than predicted and caught everyone, including nuclear power plant designers, by surprise. How could the geologists who predicted these events have been so wrong?

The reactors had been designed to withstand an earthquake of magnitude 7.9. After all, in the entire 20th century, the maximum earthquake experienced in the region was magnitude 7.8. The Tohoku earthquake on March 11 was magnitude 9.0, releasing 45 times more energy than the reactor was designed to withstand. The tsunami wave height was also significantly underestimated. The Fukushima plant was designed to withstand a tsunami of 5.7 m height. Recent estimates put the Tohoku tsunami wave height at 14 m.

In the nuclear field, policy makers often demand predictions about Earth behavior: What's the largest earthquake that will occur at the site of a nuclear power plant? Will the nearby fault move? Is this a reasonably safe location to site a geologic repository for high- level radioactive waste? The advantage of these predictions is that they provide simple and straightforward parameters for policy decision-making. The disadvantage, as we now know, is that they can't be made with the necessary accuracy.

Allison Macfarlane

Allison Macfarlane is currently an Associate Professor of Environmental Science and Policy at George Mason University in Fairfax, Virginia. She is also an affiliate of the Program in Science, Technology and Society at MIT and the Belfer Center for Science and International Affairs at Harvard University. She received her PhD in geology from the Massachusetts Institute of Technology in 1992. She has held fellowships at the Bunting Institute at Radcliffe College, the Center for International Security and Arms Control at Stanford University, and the Belfer Center for Science and International Affairs at Harvard University. From 1998-2000 she was a Social Science Research Council-MacArthur Foundation fellow in International Peace and Security. She has served on National Academy of Sciences panels on nuclear energy and nuclear weapons issues. She is currently a member of the White House’s Blue Ribbon Commission on America’s Nuclear Future. She is also presently chair of the Science and Security Board of the Bulletin of the Atomic Scientists and serves on the Keystone Center’s Energy Board. Her research focuses on environmental policy and international security issues associated with nuclear energy, especially the back-end of the nuclear fuel cycle. In 2006 MIT Press published her book, Uncertainty Underground: Yucca Mountain and the Nation’s High-Level Nuclear Waste, which explores the unresolved technical issues for nuclear waste disposal at Yucca Mountain, Nevada.

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