Although fluctuations in rotation are small and may only change the length of a day by one millisecond, they could lead to the release of vast amounts of underground energy, researchers said.
“The correlation between Earths rotation and earthquake activity is strong and suggests there is going to be an increase in numbers of intense earthquakes next year,” said Roger Bilham of the University of Colorado in the US.
Researchers looked at earthquakes of magnitude seven and greater that had occurred since 1900.
They found five periods when there had been significantly higher numbers of large earthquakes compared with other times, The Guardian reported.
They discovered that when Earths rotation decreased slightly, it was followed by periods of increased numbers of intense earthquakes.
“The rotation of the Earth does change slightly – by a millisecond a day sometimes – and that can be measured very accurately by atomic clocks,” said Bilham.
Researchers found that there had been periods of around five years when Earths rotation slowed by such an amount several times over the past century and a half.
Crucially, these periods were followed by periods when the numbers of intense earthquakes increased.
“The Earth is offering us a five-year heads-up on future earthquakes,” said Bilham.