Tech & Science

Earth's seismic activity was reduced by 50% during lockdown

The "anthropause" allowed scientists to collect new data on seismic activity.

London during  the lockdown Photo by Sam Parkman on Unsplash

London during the lockdown
Photo by Sam Parkman on Unsplash

When the coronavirus-induced lockdown hit earlier this year, the Anthropocene gave way to the "Anthropause." This term refers to the sudden silence that overcame a planet that's usually very noisy. While the pause meant that many people's lives were put on hold and their health compromised, it brought rare and precious relief to others. Wildlife thrived, and scientists were able to listen more closely to bird and whale songs than they have in decades.

The Anthropause also allowed scientists to collect unprecedented data on seismic activity. With planes downed, cars parked, trains stopped, cruise ships docked, and concerts canceled, it has been estimated that the Earth's human-induced vibrations were reduced by 50 percent between March and May of 2020.

Scientists from the Royal Observatory of Belgium and five other institutions around the world just published a study in the journal "Science" that reveals how extensively the lockdown reduced seismic activity. They found that the biggest reductions occurred in densely populated urban areas such as New York City and Singapore, but the effects were felt even in remote regions, such as an abandoned mine shaft in Germany that's considered one of the quietest places on Earth and in the interior of Namibia.

Using data gathered from 268 seismic stations in 117 countries, the scientists observed a significant reduction in seismic noise at 185 of those stations. The data revealed a "wave of silence" tracking across the planet, starting in China in late January, moving next to Italy and the rest of Europe, and then on to North America as lockdown orders were put in place.

Dr. Stephen Hicks, a professor at the Imperial College of London's Department of Earth Science and Engineering, stated in a press release:

"This quiet period is likely the longest and largest dampening of human-caused seismic noise since we started monitoring the Earth in detail using vast monitoring networks of seismometers. Our study uniquely highlights just how much human activities impact the solid Earth, and could let us see more clearly than ever what differentiates human and natural noise."

This is a boon to earthquake research. Scientists will be able to take the seismic data that was collected during the lockdown and use it to differentiate between human noises and natural seismic noises going forward. The Star quoted Prof. Mika McKinnon from the University of British Columbia, another one of the study's co-authors:

"We’re getting a much better understanding of what these human-generated wave shapes are, which is going to make it easier in the future to be able to filter them back out again."

As human noise increases, due to urban sprawl and population growth, it's getting harder and harder to hear what's happening below the surface of the Earth. And yet, this information is crucial to creating "fingerprints" of tremors in order to keep a record of what a particular fault line is prone to do – and how it could potentially threaten human populations above-ground. Dr. Hicks explained,

"It’s important to see those small signals because it tells you if a geological fault, for example, is releasing its stress in lots of small earthquakes or if it’s silent and the stress is building up over the longer term. It tells you how the fault is behaving."

The scientists say that this new data doesn't mean they'll be able to predict earthquakes with more accuracy, but it does provide a tremendous influx of data to a field of study that struggles to compete with human noise. In McKinnon's words, "It offers scientists deeper insight into the planet’s seismology and volcanic activity," and Dr. Hicks says it could "spawn new studies that help us listen better to the Earth and understand natural signals we would otherwise have missed."

Knowing the devastation that can be wrought by earthquakes, the more information we have, the better off we're all likely to be. It's nice to know that the challenges of lockdown did have silver linings for some, and that those could someday – maybe – help us to survive an earthquake.

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