Published on : 04/12/2020 – 21:02Modified : 04/12/2020 – 23:01
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Since the confinement in France, the cities are generally quieter and the birds are heard again, but they are not the only ones: the Earth, too, is heard better. Indeed, with the reduction of human activities, seismic activity has decreased. A boon for seismologists.
Almost everywhere in the large confined cities, the inhabitants rediscover the calm of the streets without traffic, less ambient noise, but also less seismic noise.
” Human activity, that is to say rail traffic, car traffic, generates vibrations of the ground and that we record continuously to all of our sensors, explains Jérôme Vergne, who works at the Institut de physique du globe de Paris (IPGP). Since confinement, the drop in human activity is reflected in a decrease in the amplitudes of the movement of the ground observed at each of our sensors, it even goes up to more than 40 or 50% in city centers. “
A decrease in background noise similar to a vacation period which could prove useful in some cases.
“ I am thinking in particular of an earthquake swarm almost under the city of Strasbourg since mid-November 2019 which may be linked to the deep geothermal activity north of Strasbourg, continues the researcher. We had installed a whole set of seismological sensors which were of very low quality with a lot of noise due to this human activity. Yes, confinement could significantly better help us understand the processes underway three, four kilometers below this city. “
On the other hand, if certain very small amplitude earthquakes could be detected thanks to confinement, it would have to last much longer to obtain sufficient relevant data.
► Read also: Coronavirus: the beneficial effects of containment for the environment
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