Researchers in the United States have warned we are likely to see a significant increase in the number of major earthquakes striking around the globe in 2018.
- 6.4 earthquake strikes near New Caledonia
- Major earthquake strikes off Mexico
- No one is safe from increased earthquake risk
United States researchers Roger Bilham of the University of Colorado and Rebecca Bendick of the University of Montana found that when Earth's rotation decreased slightly, it was followed by periods of increased numbers of intense earthquakes.
They say this small change in Earth's rotation speed could bring about increased seismic activity.
"We have had it easy this year," Mr Bilham told The Guardian.
"So far we have only had about six severe earthquakes. We could easily have 20 a year starting in 2018."
Earthquakes magnitude 7 and over
- 2008 – 12 (estimated deaths - 88,000)
- 2009 – 17 (1800)
- 2010 – 24 (320,000)
- 2011 – 20 (22,000)
- 2012 – 14 (630)
- 2013 – 18 (1500)
- 2014 – 12 (750)
- 2015 – 19 (10,000)
- 2016 – 16 (1300)
- 2017 – 6 (1100)
Earth's new rotation speed will only change the length of the day by a millisecond, but will release masses of underground energy.
"A striking example is that since 1900 more than 80% of all magnitude 7 earthquakes on the eastern Caribbean plate boundary have occurred 5 years following a maximum deceleration (including the 2010 Haiti earthquake)," the study says.
Mr Bilham told The Guardian in these periods, there were between 25 to 30 intense earthquakes a year.
"The rest of the time the average figure was around 15 major earthquakes a year," Bilham told The Guardian.
Presenting their findings at the annual meeting of The Geological Society of America, Bilham said, "It is straightforward... the Earth is offering us a five-year heads-up on future earthquakes."
Earth's rotation began one of its periodic slowdowns more than four years ago.