An earthquake happens when energy stored along cracks in the Earth’s crust — faults — is released. That creates seismic vibrations that shake the ground. Since we know where many faults are, scientists can predict generally where earthquakes might occur. When it comes to the connection with the Earth’s rotation, however, things get a bit more complicated.
Some suggest thinking about it like a spinning skirt: when the rotation speeds up, mass moves closer to the equator, and when it slows down, mass moves back out toward the North and South Poles. The idea is that if this slowing happens after a significant amount of potential energy has already built up along fault lines, or, as Bendick says, “if they’re locked and loaded,” the tiny change in the Earth’s rotation could kick earthquakes into gear.
It’s important to remember that this isn’t a foolproof prediction. It’s notoriously difficult to predict earthquakes, and this most recent hypothesis hasn’t been tested in a lab. Bilham himself said, “Of course [it] seems sort of crazy.”
But even some skeptics are willing to sign on to this prediction.
“It might be nonsense,” said geophysicist Michael Manga of the University of California, Berkeley. “I’ve worked on earthquakes triggered by seasonal variation, melting snow. His correlation is much better than what I’m used to seeing.”