Every year, more than 200,000 earthquakes are recorded on our planet, although, according to estimates, several million occur.
Many go unnoticed because they are too mild for us to feel, or because they occur in remote areas that are not monitored.
Others, the one that shook Morocco this Fridaycause numerous fatalities and cause entire buildings to collapse.
Building earthquake-proof houses and buildings is, obviously, the best strategy to avoid both human and material losses. Evacuating the areas that will be affected in advance—such as in the case of a hurricane—would also contribute in this regard.
However, the latter cannot be done—except a few minutes before—since, earthquakes are impossible to predict.
Because? What is it about earthquakes that scientists cannot say with certainty when they will occur?
Physical law
Most earthquakes occur by sudden release of stress in the earth’s crust.
This tension gradually builds up due to tectonic movements, usually along a geological fault, explains the Geological Society of the United Kingdom on its website.
But it is impossible to predict when it will happen, “basically because of the way that stress is released”Richard Luckett, seismologist at the British Geological Survey, explains to BBC Mundo.
“We know that tension is building up on the big faults and we know where they are, but we have no way of knowing when they will release it,” he says.
To help us understand the problem, Luckett uses the example of an experiment that he normally does to explain this phenomenon to children.
“If you put a brick on a piece of sandpaper and slowly remove the paper with a spring, the brick will move. You can repeat this experiment 10 times, and even if you apply the same force each time, you will see that the brick will suddenly move after different time intervals,” says Luckett.
“In physical terms is completely unpredictable“.
Fault size
What experts can at least know is where a high-intensity earthquake is likely to occur, “since these are related to the size of the fault,” Luckett clarifies.
However, this does not help predict the intensity of an earthquake, because pressure can be released in a series of small earthquakes or in one large earthquake.
The animals that can warn us
And aren’t there other signs, such as a change in the climate or the behavior of animals, that can help us predict an earthquake?
“Earthquakes do not have nothing to do with the weather and certainly no connection to climate change“clarifies the scientist.
“They are completely different systems.”
But the case of animals is interesting, he adds.
Much has been reported for a long time about how some animals show different behavior before the imminence of an earthquake.
It is said that dogs bark more or that animals are noisier in general.
This is because “when there is a large earthquake at a great distance, it causes different waves that travel across the earth. The first ones are very small, they don’t hurt, and many times we don’t even notice them,” says Luckett.
“But animals do.”
Neither now nor later
Even so, this is not very helpful when predicting an earthquake.
“Animals feel these vibrations, but this happens once the earthquake has occurred“says the expert.
“They warn us of the danger a little earlier (the time depends on the pause that occurs between the small waves and the larger ones), in the same way that alarms do.”
“And in this sense, devices are more sensitive than animals.”
In short, the expert believes that it is not—nor will it be—possible to predict earthquakes.
“What can be done is polish the way to detect the probabilities“.
*This article was originally published in February 2023 and has been updated following the earthquake in Morocco.
Keep reading:
* Morocco fights to save earthquake survivors against the clock
* The “miracle” baby who was born minutes before the Moroccan earthquake and who now lives in a tent
* GPS data could predict earthquakes
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