From March, 2013 to October, 2013, Woody and Neil Chapman lead a team of independent earth science and risk specialists to investigate the active fault issues at the Tsuruga nuclear power plant, operated by the Japan Atomic Power Company (JAPC) and the Higashidori nuclear power plant, operated by the Tohoku Electric Power Company (Tohoku EPCo).  Both nuclear power plants are in Japan.

Our article in the EoS, Transactions American Geophysical Union (publisher: John Wiley & Sons, Inc) appeared on January 28, 2014.  This article only reviews our work at the Tsuruga NPP.

Our investigation confirms that at the Tsuruga NPP, the Japan Atomic Power Company has provided adequate, clear, and convincing evidence that the fractures of concern to the Japan Nuclear Regulation Agency are not ‘active faults’ and have not moved at the site during at least the last 120,000 to 130,000 years.

Similarly, at the Higashidori NPP, there is absolutely no positive evidence that there are active faults traversing the Higashidori NPP site.

We thus consider that the presence of an ‘active fault’ at both plants has been resolved and is not a basis for action by the NRA. We urge the NRA and the utilities to enter into a dialog based on scientific evidence.

To read the submission version of the article, click here to download the PDF.

To read the abstract and gain access to the PDF of the final article, click here.

To read the presentation of this material from the American Nuclear Society PSA 2013 conference, click here.

Full Citation

Chapman, N., K. Berryman, P. Villamor, W. Epstein, L. Cluff and H. Kawamura (2014), Active Faults and Nuclear Power Plants, Eos Trans. AGU, 95(4), 33.

Author Information

  1. MCM Consulting, Baden, Switzerland
  2. GNS Science, Wellington, New Zealand
  3. Lloyd’s Register, Tokyo, Japan
  4. Geosciences Department and Earthquake Risk Management (emeritus), Pacific Gas and Electric (PG&E), San Francisco, Calif.
  5. Obayashi Corporation, Tokyo, Japan

For more information, please contact Woody Epstein: or

Publication History

  1. Issue published online: 28 JAN 2014
  2. Article first published online: 28 JAN 2014