The Big Quiet
The world has been both literally and figuratively standing still during the ongoing pandemic, scientists say. Lockdowns around the globe have drastically reduced human activity, and as a direct result, the ground is shaking far less — a silver lining for those studying seismic signals.
In fact, an international team of researchers have found that seismic vibrations generated by humans have fallen by as much as 50 percent globally, according to a new paper published in the journal Science yesterday.
“The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record,” the researchers noted in their paper.
Thanks to this quiet period, scientists were able to get an unprecedented listen to seismic signals from natural sources, including small earthquakes and volcanic eruptions.
“While the reduction is strongest at surface seismometers in populated areas, this seismic quiescence extends for many kilometers radially and hundreds of meters in depth,” the researchers wrote. “This provides an opportunity to detect subtle signals from subsurface seismic sources that would have been concealed in noisier times and to benchmark sources of anthropogenic noise.”
Quieter Than Christmas
The researchers collected data from 268 seismic stations in 117 countries, examining frequency ranges normally associated with human activity. The quiet period started in China in late January 2020, coinciding with the spread of the coronavirus and shelter-in-place orders, with Europe and the rest of the world following in March to April 2020.
“The noise level we observe during lockdowns lasted longer and was often quieter than the Christmas to New Year period,” the researchers noted in their paper, a period that normally is the most seismically quiet.
READ MORE: Coronavirus lockdowns hushed seismic noise around the world [Axios]
More on the research: The Earth is Standing Still During the Pandemic. Literally.