A recently published article by the Daily Mail UK talks about a swarm of devastating earthquakes that will arrive next year, due to the slowing down of planet earth’s rotation. This year, we had six major earthquakes, whereas, in the next, it is predicted that we will have around 20 major earthquakes. These earthquakes are expected to occur more in the tropical regions, which are home to more than a billion people.
We Are Bad at Predicting Earthquakes
Even though this seems like quite a scary news, it should also be known that predicting earthquakes is no easy task. Moreover, there are not reliable ways to predict when an earthquake will happen and what its magnitude will be. The dire threats that the recent research points to may not be true at all since we are really bad at predicting earthquakes.
Yes, there are Earthquake prone zones and the slowing down of the Earth’s rotation, even by a minuscule amount can affect the tectonic plates of the earth causing seismic activities. But there is no certainty that these earthquakes will be major, will happen in 2018 or will happen at all or not.
How The Prediction Is Done
As mentioned before, there is no certain way to predict an individual earthquake. We can issue a warning, at best since there are a lot of parameters affecting such phenomenon and also do not have a much detailed idea of what is happening between and under the tectonic plates in real time.
Earthquakes happen where the tectonic plates – the plates that make up the Earth’s crust, have a lot of potential energy build up between them. This energy, upon crossing a threshold, is released in form of seismic waves.
Scientists and researchers are aware of the location of these cracks. These cracks are also the Earthquake-prone zones. So when energy builds up in a crack, a scientist can develop a general forecast of the area. However, the cause of the energy buildup is complex and how it will exactly unfold is uncertain.
Sometimes, earthquakes are predicted by looking at historical data and by observing the trends. Sometimes, earthquakes can be predicted by observing volcanic activity or be continuously monitoring seismic activity itself. However, the 2018 earthquake activities have been linked to the slowing rotation of the earth and the pull of the moon on the earth.
The 2018 Predictions
The 2018 earthquake predictions were made by the Scientists from the University of Colorado in Boulder and the University of Montana.
By looking at the earthquake data from the past century, it seemed that these earthquakes were totally random. However, Rebecca Bendick and colleague Roger Bilham from the University of Colorado, Boulder, added another number to their equation called the “renewal interval”.
This is the amount of time needed for an earthquake zone to build up the energy needed to cause a seismic activity. You can think of these quakes as a neuron or a battery. It requires a certain amount of time to be charged up.
A certain class of earthquakes, ones having a magnitude of 7.0 or more and with a shorter renewal period of 20 to 70 years seemed to cluster over time. About every three decades, a much of earthquakes with magnitude 8.0 to 10.0 happened in large numbers. It seems as if something was causing the earthquakes to synchronize, even though they are being scattered all throughout the globe.
The researchers studied a wide range of parameters and global phenomenon to see why earthquakes were occurring in the way that they do. The different parameters include sloshing of the molten rock in the mantle, ocean circulation changes, momentum transfer between the Earth’s core and the lithosphere and so on.
The best fit in this case, however, is the change in speed of the earth’s rotation. In about 30 years or so, the earth slows down by an infinitesimally small amount. Roughly five years after every slowdown, these earthquakes appear.
This correlation was pointed out before by the Russian geophysicists Boris Levin and Elena Sasorova. Benedick and Bilham just took it a step further. They found the mechanisms that cause the quakes when the earth slows down.
When the rate of the earth’s rotation changes, it’s shape changes. It is quite like how a dancer’s skirt moves as the rotate. When the earth speeds up, the mass of moves towards the equator and when it slows down, it moves towards the poles.
This change of mass often causes potential to build up in between cracks, even though the cumulative effect is very tiny – a millimetre difference in the width of the globe. However, if a crack already had a lot of pent-up potential energy and some more is added to it, then that minuscule change is enough to cause massive seismic activities.
But that doesn’t necessarily mean 2018 will be a particularly devastating year. For one thing, the kinds of temblors Bendick and Bilham analysed happen in areas that are already earthquake-prone – Japan, New Zealand, the west coast of the United States. For people who live in those regions, there is always a risk of a quake, and it is always good to be prepared.
Their study is about probabilities, not predictions, Bendick cautioned. Earth’s slowing does not mean that a quake will happen in the next year or so, just that the likelihood may have gone up.