The worldwide lockdown led to the longest and most pronounced reduction in human-linked seismic vibrations ever recorded, sharpening scientists’ ability to hear earth’s natural signals.
Vibrations travel through the earth like waves, creating seismic noise from earthquakes, volcanoes, wind and rivers as well as human actions such as travel and industry. In the study, published in the journal Science and conducted using international seismometer networks, scientists found that human-linked earth vibrations dropped by an average of 50% between March and May this year.
“The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record,” they wrote. The work was co-led by the Royal Observatory of Belgium and five other institutions using data from 268 monitoring stations in 117 countries.
Beginning in China in late January, and followed by Europe and the rest of the world in March to April, researchers saw “a wave of quietening” as worldwide lockdown measures to slow the coronavirus pandemic took hold.
The relative quiet allowed scientists to “listen in” in more detail on the earth’s natural vibrations, said Stephen Hicks, a seismologist at Imperial College London who co-led the work. “It has yielded a new window on the natural seismic signals, and could let us see more clearly than ever what differentiates human and natural noise,” he said.
It's not yet evident what advantage this period of quiet will provide seismologists for the future, but the ability to more clearly listen to the earth's natural vibrations (and clearly distinguish them from human-made sound) should help them better predict earthquakes, for example, in the years ahead.
Original article: Reuters