Gravity signals inVented to warn against earthquakes and saVe lives 🌍

afifa (64)in #science • 6 years ago (edited)

The strong earthquakes produce anomalies in the gravitational field of the Earth: a network of gravimetric sensors can give the alarm before the arrival of the most destructive seismic waves.

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A new method of recording earthquakes could help to reduce victims and damage in areas close to the epicenter of a strong earthquake, giving the alarm from a few seconds to a few minutes before the arrival of the compression waves (those sussultorie, called waves P ) and, above all, of the most destructive secondary waves, the undulatory waves ( S waves ).
The earthquakes recorded and measured with seismographs, but an event that occurred during the 2011 earthquake in Japan opened a new line of research that has now led to the first results. The new method is based on the detection of changes in the Earth's gravitational field .

Seismograms are the method we have to detect an earthquake and measure its intensity. But a strong earthquake can alter the gravitational field of the Earth in an area more or less wide from the epicenter: this allows to launch the alarm with a small advance compared to the arrival of the seismic waves.

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ANTICIPATE THE WORST

The earthquake of 2011 was so intense (magnitude 9.1) to produce an instantaneous alteration of the Earth's gravitational field in an area of 2,000 km from the epicenter, detected by the underground laboratory of Kamioka , which houses the Super-Kamiokande for the study of rays cosmic and where research is also carried out on the gravitational field of our planet.
On that occasion Kamioka recorded an anomaly in the gravity of the planet exactly 50 seconds after the earthquake , while after another 30 seconds seismic waves arrived (which spread at 7-8 km per second).
A network of gravimeters (relatively simple instruments) well distributed on the planet, detecting variations in gravity could anticipate - albeit only slightly - the arrival of the real waves of the earthquake.

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NOTICE, NOT FORECAST

The areas less close to the epicenter of the earthquake would be short notice: it should be emphasized that this would not be an alert for something that has yet to happen, but for an event that has already happened, the consequences of which are expected in seconds .

It may seem expensive , but consider that within a few seconds people - when well prepared - can put themselves in a less dangerous situation, even at night. Few seconds are enough to stop the trains, close the gas pipelines, activate all the emergency services ...
In short, it is not a prediction system: it falls into the category of methods called early-warning , such as ShakeAlert , that is systems that give way to anticipate the arrival of seismic waves over a period of time. even short, but sufficient to activate countermeasures. Researchers who have developed the models of this system claim that at the moment the method can be applied successfully in the case of high intensity earthquakes, magnitude 8 or higher: further studies and developments of the technology would however allow to have early warning signs also for earthquakes of lower intensity.