Coronavirus closures silence seismic noise worldwide

According to new research, during blockades and other measures to control the spread of the new coronavirus, there was a global 50% drop in seismic vibrations that humans normally generate.

Because it is important: Human seismic noise can drown out signals from earthquakes, volcanic eruptions, and other geological hazards and natural sources. The 2020 “period of silence” can help improve warning systems by offering the opportunity to separate natural sounds from those generated by human activity.

Drive, drill, walk, fly and other human activities vibrate the Earth’s surface, creating seismic noise.

What they found: Using data from 268 seismic stations in 117 countries, the researchers measured the effects of blockages on high-frequency (4–14 Hz) seismic ambient noise (hiFSAN), which corresponds to vibrations typically generated by human activities.

  • They looked at the effects of the blockades at 185 stations and found a “near-global reduction in noise, which started in China in late January 2020, followed by Europe and the rest of the world” from March to April 2020.
  • The reduction in noise level lasted longer and was sometimes calmer than in the period from Christmas to New Year, Thomas Lecocq, a seismologist at the Royal Observatory of Belgium, and colleagues around the world report Thursday in the magazine . Science.
  • Falls were most pronounced in the most populated areas (New York and Sri Lanka), but were also observed in the least populated regions (for example, the Black Forest of Germany).

The panorama: “This is the first time that we know that this type of effect is visible in such a wide area, throughout the world, and for such a long period of time,” says Lecocq.