Tiny Slowdown in Earth's Rotation Could Unleash Major Earthquakes

A tiny slowdown in Earth's rotation next year could trigger more earthquakes than usual, new research suggests.

Past periods of slow rotation over the last 100 years have coincided with more earthquakes than average, according to research presented last month at the annual meeting of the Geological Society of America.

"The numbers of earthquakes that have occurred each year in the past century are well known. The changes in Earth's rotation rate are also well known," study co-author Roger Bilham, a geophysicist at the University of Colorado Boulder, said in an email to Live Science. "All we have done is to compare these two well-known lists of numbers and report an interesting and useful relationship."

The basic idea is that as the Earth's spin slows slightly, the equator shrinks. However, tectonic plates don't shrink as easily, meaning the edges of the plates get squeezed. Although this amount of squeezing isn't huge, it does put added stress on plate boundaries that are already under stress, where earthquakes are more likely, Bilham said.

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