Current Affairs

Issue

The ongoing Covid-19 pandemic has brought the world to a grinding halt and high-frequency noise generated by industrial plants, traffic, and other human activities fell sharply during a period marked by lockdowns and social isolation.

 

Background

Soon after the COVID-19 pandemic was declared a global health emergency earlier this year, countries across the world responded by imposing stringent lockdown measures and enforcing social distancing norms. 

 

Details

• A team of seismologists studied the impact of the coronavirus pandemic on noise-levels worldwide and found that high-frequency noise caused by human activities dropped by as much as 50 percent between March and May, this year.

• The period of quiet induced by this global health crisis is the longest and most prominent noise reduction on record.

• The team analysed data collected from 268 seismic sensors located across 117 countries, and found that human-generated noise had fallen significantly in 185 of them.

• The most substantial declines were observed in highly-populous urban areas like Singapore and New York as well as tourist hotspots like Barbados and in European ski resorts.

• Seismic noise refers to vibrations within the Earth, which are triggered by natural and man-made phenomena like earthquakes, volcanoes, and bombs. Seismometers, specialised devices that record ground motions, also capture seismic noise.

• Everyday human activity such as road traffic, manufacturing in factories, the sound produced by planes, or simply people walking down the street also generates seismic noise, which is recorded as a near-continuous signal on seismometers.

• The sound signals created by human beings are often referred to as anthropogenic seismic noise.

• Many scientists have noticed favourable changes in the environment, such as reductions in nitrous oxide emissions and improved air quality, due to the pandemic.

• But the team of seismologists from around the world has found that the coronavirus outbreak also resulted in unparalleled noise reduction globally.

• Low noise levels of background noise during COVID-19 lockdowns could thus allow detection of signals from new sources in areas with incomplete seismic catalogs.