Research published in the journal Science has shown that lockdown measures to combat the spread of COVID-19 led to a 50% reduction in seismic noise observed around the world in early to mid 2020.
The article is the result of a unique collaboration involving 76 authors from 66 institutions, including members of Résif, in 27 countries. This exceptional teamwork has made it possible to process and analyse the masses of data from more than 300 stations in global seismic monitoring networks such as Résif. This is the first global study of the impact of the pandemic on solid earth.
The analysis highlighted the “wave” moving through China, then into Italy and the rest of the world. The greatest reductions in seismic noise were found in urban areas, but also on sensors buried hundreds of metres underground and in more remote areas, such as sub-Saharan Africa.
It reveals a strong concordance between seismic noise and human mobility (recorded by mobile phone mapping applications and made public by Google and Apple). Seismic data are thus proving to be a tool for monitoring human activity independent of any personal data collection.
Will this period of silence in terms of seismic noise allow the detection of new types of signals? With increasing urbanization and a growing world population, more and more people will be living in geologically hazardous areas. It will therefore be more important than ever to characterize anthropogenic noise so that seismologists can better listen to the Earth, especially in cities, and monitor the movement of the ground beneath our feet.
- Claudio Satriano, IPGP
- Jérôme Vergne, Eost
- Marc Grunberg, Eost