Sunday, November 19, 2017

2018 Could See Spike In Large Quakes, Swarm Of Strong And Shallow Quakes (M7.0, M6.6, M6.4) Hit New Caledonia

As Earth's rotation slows, 2018 could see a spike in large earthquakes

Every so often, the Earth’s rotation slows by a few milliseconds per day. This is inconsequential to the average human, and causes only mild annoyance to the people whose job it is to measure Earth’s rotation with great precision.

That may be about to change, if the hypothesis set out by two geologists proves true. In a study published in Geophysical Research Letters earlier this year, Roger Bilham of the University of Colorado and Rebecca Bendick of the University of Montana predict that, because of Earth’s slowing rotation, the world will see a significant spike in large earthquakes in 2018.

To make this prediction, Bilham and Bendick studied every earthquake since 1900 that recorded more than 7.0 on the moment magnitude scale. They found that approximately every 32 years, there is an uptick in these large quakes. The only factor that strongly correlates is a slight slowing of the Earth’s rotation in a five-year period before the uptick.

“Of course that seems sort of crazy,” Bendick told Science. But think through it a little and it might not seem so outlandish. The Earth’s rotation is known to go through regular decades-long periods in which it slows down and speeds up. Even seasonal changes, like a strong El NiƱo, can affect the planet’s rotation.

“The inference is clear,” Bilham told the Guardian. “Next year we should see a significant increase in numbers of severe earthquakes.” Instead of an average of about 15-20 large earthquakes, we might see 25 or 30 in 2018.

A swarm of strong earthquakes is currently hitting New Caledonia since 9:30am UTC. The series started with a strong M6.4. Six hours later, a M6.6 jolt hit at almost the same spot, a few tenths of kilometers (miles) east of Tadine. Now a powerful M7.0 hit just a few minutes ago at 10:43pm UTC. USGS is currently reporting 12 earthquakes with magnitudes bigger than M4.7 (the lowest actually), but only counts the significant earthquakes (M>4.5) around the world. And the swarm continues…

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