NZ scientists slam 'upsurge' earthquake theory

NZ Herald Staff,
Publish Date
Monday, 20 November 2017, 1:22p.m.

New Zealand earthquake scientists have been critical of a theory from two American scientists that the frequency of earthquakes is linked to a slowing in Earth's rotation, one saying "I tend to think of them in the context of (Moon Man) Ken Ring".

Last month, Roger Bilham, from the University of Colorado at Boulder, and Rebecca Bendick, from the University of Montana, presented a paper at a conference that posited that a year with a high number of earthquakes around the world coincided with a slowing in the rotation of the Earth.

"A striking example is that since 1900 more than 80 per cent of all earthquakes on the eastern Caribbean plate boundary have occurred five years following a maximum deceleration (including the 2010 Haiti earthquake)."

The paper concludes that 2017 marks six years since deceleration began in 2011, "suggesting that the world has now entered a period of enhanced global seismic productivity with a duration of at least five years".

GNS Science have commented that the paper has not been peer-reviewed and has no detail to examine, while Dr Virginia Toy from the Department of Geology at the University of Otago says correlations are often made between natural events and other phenomena.

"Some of these yield statistically defendable correlations; others don't," she said.

"I tend to think of them in the context of Ken Ring... the man who writes about apparent statistical correlations between the phase of the moon and the weather.

"(The Americans' paper) sounds like we will get a jump from six to 20 large earthquakes per year. I don't think this is likely."

Dr Tim Stahl, a lecturer in tectonic geology from the University of Canterbury, says it is difficult to judge the scientific merit of the claims being made until additional testing is carried out by other research groups.

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