Anthropogenic Seismic Noise & COVID-19

Reduction of anthropogenic seismic noise due to COVID-19 lockdown

-- Sandro Chatterjee

The Planet Earth is still trying its best to get rid of the unwanted guest, COVID-19. The impact of the virus is going to have a prolonged effect on the history of mankind. The down falling economies, joblessness, death of an entire generation are the harshest truth to stand with. But as the earth already refused to surrender in this battle vs. COVID -19, scientists all around the globe are looking for every positive impact in the upcoming days due to this deadly virus and the positive effects are now being signaled by the pulse of a seismometer.

The lack of human activities due to this prolonged lockdown caused human linked vibrations to be decreased by 50% between March and May 2020. The quiet period caused by the increasing social distancing, closure of industries, pubs, hotels, stadiums, and movies is the longest and most pronounced quiet period of Seismic noise ever recorded. The research work, led by Royal Observatory of Belgium and Imperial College London shows the dampening effects are most prominent in the densely populated areas. The quietness and the decreased human-generated noise are helping the researchers to accurately differentiate between natural and human seismic noises and are allowing them to detect previously concealed earthquake signals. The study also found the signatures of this lockdown measures on sensors buried hundreds of meters under the ground in remote areas. Researchers are eager to name this quiet period as “Anthropause”, as the anthropogenic activities are minimal and are the main causes to create this historical period. 

Lockdown in Times Square, New York City, United States of America (SOURCE: LEO CUNHA MEDIA/ISTOCK/GETTY IMAGES PLUS)

The data have been gathered from a global network of 268 seismic stations in 117 countries across the world and it indicates a sharp reduction in noise from 185 of those stations. Most prominent dampening and the largest drop in vibrations are found from the most densely populated cities like Singapore, New York, etc. Countries like Barbados, where lockdown hit the peak tourist season; saw 50 to 55 percent decreases in the seismic noise.

The reduced anthropogenic noise in Brussels, Belgium after lockdown (source: Royal Observatory of Belgium)

As the urbanization and industrialization took over the Planet Earth over the past few decades, the human-generated noise increased by 10 to 15 folds. Due to this lockdown, researchers got the opportunity to measure the natural noise of the earth precisely without the interruption of anthropogenic input. Previously concealed earthquake signals are ever prominent on the seismometers and more importantly, this can help the researchers to comment and warn more accurately on future natural disasters. This is the perfect time for them to understand the Earth like never before along with the Human-Earth interaction in the field of Seismology and Global Tectonics. The accurate interpretation regarding the plate movements, causing the earthquake can help to kick start a new field of study and extend the Geology and Geophysics research horizon in the future. 

Original article: Global quieting of high-frequency seismic noise due to COVID-19 pandemic lockdown measures. DOI: 10.1126/science.abd2438