More than 200.000 earthquakes are recorded worldwide each year, although the real number is estimated to be several million. Many earthquakes go unnoticed, either because they are so subtle that they are imperceptible to our consciousness, or because they occur in isolated regions that lack adequate monitoring. Humans have always tried to predict earthquakes.
In this article we are going to tell you if you can predict earthquakes and what advantages it would give.
Why can't earthquakes be predicted?
Building earthquake-resistant structures is undoubtedly the most effective strategy to mitigate both human losses and material damage. Furthermore, preventive evacuation of potentially affected areas would further contribute to this objective.
However, the latter cannot be achieved except with a few minutes' notice, due to the inherent unpredictability of earthquakes. Most earthquakes are the result of the abrupt release of tension accumulated within the Earth's crust.
According to the website of the Geological Society of the United Kingdom, this stress builds up progressively as a result of tectonic movements, which usually occur along a geological fault. However, it remains impossible to determine when this event will occur, as Richard Luckett, a seismologist at the British Geological Survey, explains, “mainly due to the way in which this stress is relieved.”
"We know that stress builds up along major faults and we have identified their locations, but we lack the means to predict when this energy will be released," he says. To elucidate the issue at hand, Luckett uses an illustrative experiment that he often performs to explain this phenomenon to children.
Luckett says: “By placing a brick on a piece of sandpaper and gradually pulling on the paper using a spring mechanism, the brick can be observed to move. This experiment can be performed 10 times and, despite applying the same force consistently, the brick will be seen to move at varying intervals during each test. “In physical terms, an earthquake is completely unpredictable.”
Fault size
Experts can determine the possible locations of major earthquakes, as Luckett points out, stating that "they are related to the size of the fault." However, This knowledge does not help predict the magnitude of an earthquake., since the pressure can be released by a sequence of minor tremors or a single, large earthquake.
Animals capable of alerting us
Aren't there additional indicators, such as changes in climate or changes in animal behaviour, that can help us predict an earthquake? "The occurrence of earthquakes has no relation to weather conditions and there is no unequivocal association with climate change," the scientist explains. The systems in question are completely different from each other. However, He notes that the situation regarding animals is particularly intriguing.
Over a long period, much has been reported about variations in the behaviour exhibited by certain animals in the run-up to an impending earthquake. It is often claimed that canines tend to bark more frequently, or that animals in general make much more noise.
According to Luckett, this phenomenon occurs because "when a major earthquake occurs at a considerable distance, it generates several waves that propagate through the Earth. The initial waves are quite minor, do not cause damage, and often go unnoticed. But animals do." However, This does not provide significant help in the effort to predict an earthquake.
"Vibrations are perceived by animals even though they occur after the actual earthquake event," says the expert. They provide us with a timely warning of impending danger, whose duration depends on the interval between the minor and major waves, similar to the function of alarms. In this sense, the devices show greater sensitivity than that of animals.
The expert says that predicting earthquakes is not feasible at present and will remain so for the foreseeable future. One possible course of action is to improve the methods used to identify probabilities.
Can earthquakes be predicted?
Thanks to the digital instrument developed by Társilo Girona, a researcher affiliated with the Institute of Geophysics at the University of Alaska Fairbanks in the United States, together with his colleague Kyriaki Drymoni from the University of Munich in Germany, it will soon be possible to predict earthquakes several months in advance.
Research conducted in this field addresses a controversial issue, since Frequent false alarms can result in economic turmoil and social ridicule. Accordingly, their pioneering digital tool seeks to predict earthquakes and ultimately provide early warnings that facilitate evacuations and save lives. This earthquake detection method is based on machine learning techniques.
They developed an algorithm designed to identify anomalous events within seismic activity data, subsequently extracting information from these events to facilitate predictions. This model was subjected to retrospective tests that They included a magnitude 7,1 earthquake that occurred in Alaska in 2018, as well as two earthquakes with magnitudes of 6,4 and 7,1 in California in 2019.
The findings are disturbing: major earthquakes of high magnitude occurred after a three-month period characterized by unusually low magnitude seismic activity (less than 1,5) in 15 to 25 percent of the areas affected by the severe earthquake. These events are classified as “precursor earthquakes,” which can serve as indicators of an impending major tremor.
Limitations of the study: Precursor earthquakes are associated with an increase in the pressure of “interstitial fluids”. In fact, when the pressure of these fluids inside a rock increases significantly beyond the threshold of frictional resistance between two blocks along a geological fault, an earthquake is initiated.
Regardless of this, using their model, the researchers achieved an 80% probability of predicting an earthquake up to 30 days before its occurrence and an 85% probability just a few days before the event. This is truly impressive. However, it is important to note that this study focuses on areas where earthquakes of magnitude greater than 6,4 have occurred, a phenomenon that has not been observed uniformly across all regions over the past 30 years.
I hope that with this information you can learn more about whether earthquakes can be predicted and why.