Scientists say there could be twice as many earthquakes in 2018 – so where is most at risk?
This year has already seen three earthquakes with a magnitude of at least 7 – one measuring 7.9 off the coast of Alaska, another off Honduras that registered 7.6, and a third in Peru with a magnitude of 7.1. Only two casualties were reported, both in Peru, but the arrival of three strong quakes in as many weeks has caught the attention of scientists – there were just seven with a magnitude of 7 or more throughout the whole of 2017.
In fact, geologists predict there could be twice as many earthquakes in 2018.
What's going on underground?
According to scientists, there is a strong link between the speed of the Earth's rotation and seismic activity. You won't have noticed, of course, but since 2011 the planet has been spinning ever-so-slightly slower than usual (we're talking about a few thousandths of a second). However, that tiny fluctuation could be triggering intense activity deep underground.
A report by Roger Bilham of the University of Colorado and Rebecca Bendick of the University of Montana, presented at the annual meeting of the Geological Society of America last month, argues that at least five historic periods of intense seismic activity - with double the usual number of major earthquakes - were preceeded by periods of around five years when the Earth's rotation slowed slightly.
"It is straightforward," Bilham told The Observer. "The Earth is offering us a five-year heads-up on future earthquakes."
He added: "The inference is clear. Next year [2018] we should see a significant increase in numbers of severe earthquakes."
Which countries are most at risk?
It is hard to predict where any extra earthquakes might occur, but Bilham said that the majority of intense earthquakes that followed a slowing of the Earth's rotation came in tropical regions.
As the map below of 2017's earthquakes shows, they generally occur along tectonic plate boundaries and especially on the Pacific Ring of Fire. Last year's biggest tremors, in terms of magnitude, occurred in Mexico, Papua New Guinea, Russia, Philippines, Iran and New Caledonia.
Greece, Italy and Turkey are among Europe's most earthquake prone countries as they sit on the meeting point of the African and Eurasian tectonic plates. Among the most notable in Greece's recent history was the 1953 quake that struck Kefalonia and Zakynthos, killing 476. The 1999 Athens earthquake, meanwhile, which had a magnitude of 6, killed 143 people.
"Greece can experience earthquakes and earth tremors," the Foreign Office warns. "You should familiarise yourself with safety procedures in the event of an earthquake and follow advice given by the local authorities."
Turkey's deadliest recent earthquakes were the 2011 Van earthquake, during which 604 were killed, and the 1999 ?zmit earthquake, which had a magnitude of 7.6 and resulted in more than 17,000 deaths.
According to the 2015 World Risk Report, compiled by the United Nations University for Environment and Human Security (UNU-EHS), both Greece and Turkey are among the countries in Europe where a natural disaster is most likely to strike.
The report assisgned a risk percentage to a total of 173 countries, based on the chances of experiencing earthquakes, storms, floods, droughts and sea level rises. Greece's rating was 7.36 and Turkey's 5.52, higher than Britain's (3.71), Italy's (4.88), France's (2.79), Spain's (3.38), Croatia's (4.24), Germany's (3.24), Switzerland's (2.61), Sweden's (2.26), and Russia's (3.78), among others, but lower than the likes of Albania (10.01) and - on account of its susceptibility to sea level rises - The Netherlands (8.76).
However, Greece and Turkey are quite some way off the countries around the world where a natural disaster is most likely to occur, such as in The Philippines (27.52), Bangladesh (19.81) and Cambodia (16.9).
Natural disasters | The 20 countries most at risk
Qatar (0.1) was rated the least at risk from natural disaster, followed by Malta (0.61) and Barbados (1.16). Those countries that appear grey on the map above did not feature in the study.
Natural disasters | The 20 safest countries
The report also took into account how well prepared each country is to deal with a disaster. "Risk is at its highest where a high level of exposure to natural hazards coincides with very vulnerable societies," it explained.
