With roughly one-third of the world’s population on lockdown, our planet has fallen silent. So silent, in fact, that the Earth has quite literally stilled—a reduction in the hum of human activity has caused a decrease in the Earth’s crust vibrations, scientists say.
As Nature explains, on a daily basis, various man-powered movements contribute to background seismic noise, or a persistent vibration of the Earth’s crust: engines firing up in a factory, a truck roaring down a highway, the rumbling of a train pulling into a station. Individually they’re insignificant, but taken together they weave a blanket of high-frequency sounds that make it more difficult for seismologists to detect signals occurring at the same frequency, such as a brewing volcano or the aftershocks of an earthquake.
But with many of these motions on pause during the COVID-19 pandemic, researchers are observing less seismic noise. Seismologists at the Royal Observatory of Belgium in Brussels noticed that vibrations due to human activity dropped by about one-third after the city introduced coronavirus containment measures, according to seismometer data.
And seismologists across the globe are seeing the same effect. Stephen Hicks, a faculty member in the Department of Earth Science and Engineering at Imperial College London, posted to Twitter a graph showing lower average seismic noise levels in the United Kingdom following coronavirus measures:
The #covid19UK lockdown as seen by a seismometer. This week has seen a reduction in average daytime background seismic noise level (purple line). Data is from @BGSseismology station SWN1 located close to the M4 motorway, so this probably reflects less traffic out on the roads. pic.twitter.com/uNhtKmeCdf
— Stephen Hicks ???????? (@seismo_steve) March 26, 2020
Celeste Labedz, a geophysics PhD candidate at the California Institute of Technology, also reported lower seismic noise levels in Los Angeles:
Here's daily mode noise power from a station in Los Angeles over the past month; the drop is seriously wild.
— Celeste Labedz (@celestelabedz) March 26, 2020
This respite in seismic noise, while it lasts, may allow scientists to better study the natural activity of the Earth’s crust. Researchers, including those who use the impact of crashing ocean waves to predict volcanic behavior and those responsible for triangulating the location of an earthquake’s epicenter, may be able to detect more minute changes and gather more precise data, possibly leading to a geological boon.
One of very few positives to come of the coronavirus crisis has been the chance for us to appreciate the joys of nature—and now, for us to better understand the workings of this planet that we inhabit. So let’s grant ourselves this spring of hope! We need it more than ever!