U-M: Seismometer at Michigan Stadium measures 30% reduction in noise levels during COVID-19 closures

Days of coronavirus: An empty Stadium Blvd. in Ann Arbor near The Big House. (Meredith Bruckner)

ANN ARBOR – With less people out on the streets, Ann Arbor has been eerily quiet -- and now science is backing it up.

A vibration-sensing seismometer that normally measures ground shaking from fans at football games at Michigan Stadium is now being used to capture the quiet during the coronavirus pandemic.

The device is being used to study the decrease in ground-motion noise by professors at U-M’s Department of Earth and Environmental Sciences Ben van der Pluijm and Jeroen Ritsema.

An additional portable digital seismometer is also being used on an all but abandoned central campus.

The results?

An average weekly noise level reduction of 30% at Michigan Stadium and a 50% reduction in the 1100 North University Building on campus, reported the researchers.

“It is now easier to hear Earth’s voice above the anthropogenic noise,” Ritsema, a professor of geophysics, said in a statement. “We might learn something about how anthropogenic noise affects the quality of our seismic recordings, and it may help us identify quieter locales for routine earthquake monitoring.”

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Seismologists around the world are measuring the drop of seismic noise levels since global stay-at-home orders have been enforced after the rapid spread of COVID-19.

Although the devices are designed to record ground motions produced by earthquakes, seismometers can also measure traffic on busy city streets and vibrations generated from a crowd at a packed Michigan Stadium during a home football game.

“This coronavirus-driven stay-home order creates a unique situation in city noise conditions, similar to the reduction in atmospheric contrails due to less flying,” van der Pluijm, an expert on the societal impacts of geological hazards, said in a statement. “This special situation has piqued the interest of researchers around the world.”

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