Slower Earth, More Earthquakes?

The link between Earth’s rotation and seismic activity was noted in a paper by Roger Bilham and Rebecca Bendick presented at the annual meeting of the Geological Society of America.
They contend that the  correlation between Earth’s rotation and earthquake activity is strong and suggests there is going to be an increase in numbers of intense earthquakes in 2018.
In their study, Bilham and Bendick looked at earthquakes of magnitude 7 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. “In these periods, there were between 25 to 30 intense earthquakes a year,” said Bilham. “The rest of the time the average figure was around 15 major earthquakes a year.” The researchers searched to find correlations between these periods of intense seismic activity and other factors and discovered that when Earth’s 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.