Scientists have learned to predict earthquakes by changing gravity

To do this, scientists use signals that propagate at a speed of about 300 thousand km/s, and can be

recorded long before the relatively slowseismic waves (they move at a speed of 8 km/s per second). Seismologists discovered sudden changes in gravity caused by displacement of the Earth's internal mass or PEGS (fast elastic-gravity signals) relatively recently. Using them, it is possible to calculate the approach of earthquakes long before they occur.

However, the gravitational effect of the phenomenon is very small. It is less than one billionth of the Earth’s gravity. Therefore, PEGS signals can only be recorded for the strongest earthquakes. In addition, the process of their generation is complicated: they not only appear directly at the site of the earthquake, but also spread deep into the Earth.

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Until now there has been no reliable methodfixation of PEGS signals. A new algorithm from researchers at the German Research Center for Geosciences can capture signals with high accuracy. The researchers were also able to show that the signals allow inferences to be made about the strength, duration and mechanism of earthquakes. A study about this appeared in the journal Earth and Planetary Science Letters.

The phenomenon itself is due to the fact that the earthquakesharply shifts rock slabs in the bowels of the Earth and thus changes the distribution of mass. With strong earthquakes, this displacement can reach several meters. “Since gravity, which can be measured locally, depends on the mass distribution near the measuring point, each earthquake produces a small but instantaneous change in gravity,” said research coordinator Wang Zhongjiang.