The social isolation measures adopted to contain the new coronavirus are making Earth quieter – at least for the sensitive "ears" of seismographs.
Human activity, such as the circulation of people and automobiles, generates vibrations that affect the measurements of seismic instruments. Thanks to the social isolation decreed to face the covid-19 pandemic, there was a drastic decrease in movement and, as a consequence, seismographs detected less noise.
The interferences we cause in the vibrations of seismic movements are called “anthropogenic seismic noises. In addition to finding the circulation of people and vehicles in this category, we can also mention industrial machines and even concerts.
In Belgium, scientists at the Royal Observatory report a 30% reduction in this amount of human noise since the beginning of the social isolation adopted in the country. Belgium accounts for almost 14,000 cases and more than 800 deaths, and has taken measures such as closing schools and restaurants and banning all non-essential travel until April 19.
According to CanalTech, seismologist Stephen Hicks of Imperial College in the United Kingdom recently shared data from the British Geological Survey that reveal a reduction in seismic activity in the country.
There was also a radical drop in seismic activity in Los Angeles, in the United States; Paris, France; and in Auckland, New Zealand. Normally, noise reductions of this dimension only occur around Christmas time, according to seismologist Thomas Lecocq, from the Royal Observatory of Belgium.
The #covid19UK lockdown as seen by a seismometer. This week has seen a reduction in average daytime background seismic noise level (purple line). Data is from @BGSseismology station SWN1 located close to the M4 motorway, so this probably reflects less traffic out on the roads. pic.twitter.com/uNhtKmeCdf
— Stephen Hicks 🇪🇺 (@seismo_steve) March 26, 2020
However, not all seismographs will experience these sudden changes, since the vast majority of these instruments are installed far from cities or buried in the ground, precisely to avoid the influences of human activities.
Still, this "silence" helps scientists achieve a clearer seismic reading. This means that, contrary to what has been revealed, Earth's normal seismic activities have not been altered – we are the ones that are quieter.