For centuries, science has searched for a reliable way to anticipate earthquakes. Researchers around the world are working to find what they call “precursory signs” that is, signs that warn us that an earthquake is going to occur. Chemical signals, fluctuations in the geochemistry of groundwater, electromagnetic effects in the upper atmosphere, and even changes in animal behavior have been analysed, but we have not made great progress.
At present, established earthquake warning systems provide, at best, barely a minute or two notice, so many researchers were beginning to get impatient and consider that we may not be able to find those precursor signals.
Anticipation of earthquakes?
However, this week, the question has been reopened with the publication of an interesting study in the Science Magazine that could open a window of opportunity to get ahead by up to two hours in the case of the most intense earthquakes. Maybe two hours doesn’t seem like too much time, but it can mean the difference between life and death by offering the possibility of carrying out evacuation plans.
The scientific paper is signed by two French seismologists, belonging to the Côte d’Azur University and the Institut de Physique du Globe de Paris, who analyzed high-speed GPS time series before 90 different earthquakes of magnitude 7 or greater to try to find a precursor signal common to all of them. In his study, titled “The precursor phase of the great earthquakes” French researchers show the detection of “a subtle signal that emerged from noise about 2 hours before these large earthquakes occurred.”
How does humanity understand this new study?
To better understand the published study, we should know that, broadly speaking, earthquakes occur when two blocks of the earth’s crust, attached along a fault line, accumulate tension until they slip abruptly.
Precisely this is the key because experts have been debating for a long time if this breakout is really abrupt and instantaneous or if it starts slowly, increasing speed until the breakout. If so, this precursor phase could be detected in advance and although different precursor signals for individual earthquakes have been detected in recent decades (and always after they have occurred), the truth is that “We have never detected a signal that can be applied to all earthquakes.”
new study
This is where this new study comes in, stating that earthquakes begin with an exponential acceleration of slower slip lasting approximately two hours. The work published by the French seismologists is based on GPS time series analysis and for this they collected records from GPS stations close to the earthquakes.
These GPS stations are capable of capturing the movement of the earth every five minutes with an accuracy of a few millimeters. The result was over 3,000 times series of moves in the 48-hour windows leading up to the major breakouts.
The study is interesting but it is also advisable to be cautious and not hastily launch the bells on the fly. Firstly, because the method is not yet applicable today: the results obtained have been achieved “after the fact” since the existing monitoring systems still cannot capture this signal in real time.
In the future, perhaps not too distant, technology will advance to achieve that goal and save valuable time in which the population could be evacuated or with which “to be able to retire to safe havens before the most catastrophic earthquakes.”