Seismology: Japan must admit it can't predict quakes

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Japan's government is still failing to protect the public against earthquakes, six years on from the devastating magnitude-9.1 Tohoku earthquake of 2011. In my view, it urgently needs to abandon flawed, old policies and focus instead on implementing effective countermeasures that are based on sound research.

Despite my earlier advice (R. J. Geller Nature 472, 407409; 2011), the government continues to claim that a magnitude-9 earthquake is highly likely in the Tokai–Nankai district during the next 30 years. This claim is based on the false hypothesis that great earthquakes of magnitude 8 or more occur cyclically (see Y. Y. Kagan et al. Seismol. Res. Lett. 83, 951953; 2012). Clinging to such repudiated models even after the 'unexpected' 2011 Tohoku quake is, in my view, cognitive dissonance on a massive scale.

In my 2011 Comment article, I also advocated repeal of Japan's 1978 Large-Scale Earthquake Countermeasures Act (LECA). LECA is based on the false premise that precursors of a great earthquake in the Tokai district can be detected accurately enough for a legally binding three-day state of emergency to be declared. However, the act is still in place. The government intends to tweak it to cover a larger land area, while authorizing the issuance of warnings that fall short of a state of emergency (see 'Don't rely on quake predictions', The Japan Times 7 July 2016).

I urge the government to explicitly inform the public that prediction of imminent earthquakes is currently impossible. It should repeal LECA and adopt earthquake countermeasures that are based on sound science.

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  1. University of Tokyo, Japan.

    • Robert J. Geller

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