![]() ![]() There’s Less Air PollutionĪs cities and, in some cases, entire nations weather the pandemic under lockdown, Earth-observing satellites have detected a significant decrease in the concentration of a common air pollutant, nitrogen dioxide, which enters the atmosphere through emissions from cars, trucks, buses, and power plants. “Normally we wouldn’t pick up a 5.5 from the other side of the world, because it would be too noisy, but with less noise, our instrument is now able to pick up 5.5’s with much nicer signals during the day,” Koelemeijer said. For seismologists who study seismic signals from Earth’s interior-rather than other sources, including people, animals, even storms-quarantines seem to have made it easier to listen. Lecocq shared his approach online, and seismologists in the United States, France, New Zealand, and elsewhere are now seeing the effects of their country’s own social-distancing measures on seismic activity. The drop in activity, he said, was “immediate.” Right now, daytime in Brussels resembles Christmas Day. Lecocq checked seismic data the day before Belgium began a nationwide lockdown, and then the following morning. Today, it provides a fascinating glimpse of the ebb and flow of a bustling city Lecocq has found that when it snows, anthropogenic seismic activity decreases, and on the day of a road race, it spikes. Seismic stations are usually found well outside metropolitan areas, away from vibrations that could obscure subtle tremors within Earth’s interior, but the Brussels station was established more than a century ago, before a city grew around it. The trend started with Thomas Lecocq, a seismologist at the Royal Observatory of Belgium, in Brussels. Seismologists around the world have noticed the same effect Koelemeijer detected in London, and at more traditional stations than a fireplace. Here are four ways the pandemic is being felt across land, air, and sea. In a bittersweet twist, the surreal slowdown of life as we know it has presented researchers with a rare opportunity to study the modern world under some truly bizarre conditions, and they’re scrambling to collect as much data as they can. The “wow” moment is short-lived, of course, because the explanation is not a quirk of nature or some other benign eccentricity, but a catastrophic virus that has sickened and killed thousands, crumpled economies, and plunged public life into a fearful limbo with no easily discernible end.īut the response to the pandemic has unwittingly produced some other large-scale, though less conspicuous, effects. At first glance, this is indeed a fascinating observation, the kind of factoid that might appear on the underside of a Snapple cap. Koelemeijer said she briefly geeked out over the recent data before reality set in. “It’s very literally reflecting a slowdown of our lives,” Koelemeijer told me over Skype. Now, with fewer trains running, the spikes seem to come at random. With fewer trains, buses, and people pounding the pavement, the usual hum of public life has vanished, and so has its dependable rhythms: Before the spread of COVID-19 shut down the city, Koelemeijer could plot the seismometer’s data and see the train schedule reflected in the spikes, down to the minute. Since the United Kingdom announced stricter social-distancing rules last month, telling residents not to leave their home except for essential reasons, the seismometer has registered a sharp decrease in the vibrations produced by human activity. ![]() The apparatus, though smaller than a box of tissues, can sense all kinds of movement, from the rattle of trains on the tracks near Koelemeijer’s home to the waves of earthquakes rolling in from afar. Koelemeijer, a seismologist, has a miniature seismometer sitting on a concrete slab at the base of her first-floor fireplace. From inside her living room in London, Paula Koelemeijer can feel the world around her growing quieter. ![]()
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