Major earthquakes can be detected 2 hours in advance
Quentin Bletery and Jean-Mathieu Nocquet, the seismologists who conducted the study, said, if they are right, it may be possible to detect earthquakes through GPS measurements a few hours before they happen. “Conceptually, this tells you it’s possible to do this. It’s a big step forward,” Beletery says in a statement.
The study, published in the journal Science, analyzed data from GPS stations located around the known locations of earthquakes of 7.0 or higher within 48 hours before the relevant earthquake. The researchers found that in the last two hours before an earthquake, ground motion usually begins to align with the expected motion. It was observed that this alignment intensified as the earthquake time approached. The aim of the researchers is to detect the precursors, which are the fingerprints of large earthquakes. And these movements may be long-sought pioneers.
Over the past few years, researchers have obtained and analyzed precise GPS data for the geographic areas surrounding the epicenters of 90 earthquakes above magnitude 7.0. A pattern of shear has been unequivocally observed between tectonic plates that causes the soil on them to move in a measurable, horizontal direction.
There are technological constraints
Although GPS data can detect plate motion prior to earthquakes of 7.0 and above, seismologists are far from turning it into a tool for predicting earthquakes. Because today’s instruments are not good enough to detect this movement in advance. To detect the precursor of an earthquake, existing equipment would need to be 50 times more sensitive, the researchers say.
This is a huge technological gap and we don’t have the technology yet to do it. However, adding more GPS stations can help. This study shows that a reliable earthquake system can be designed based on a sensitive GPS observation system. On the other hand, Bürgmann notes that more work needs to be done to prove that such an antecedent exists for all, or at least for most, major earthquakes. Bürgmann also adds that some improvements need to be made in GPS technology so that individual events can be measured around the clock.