COVID-19 Societal Response Captured by Seismic Noise in China and Italy

Abstract

Seismic noise with frequencies above 1 Hz is often called “cultural noise” and is generally correlated quite well with human activities. Recently, cities in mainland China and Italy imposed restrictions on travel and day-to-day activity in response to COVID-19, which gave us an unprecedented opportunity to study the relationship between seismic noise above 1 Hz and human activities. Using seismic records from stations in China and Italy, we show that seismic noise above 1 Hz was primarily generated by the local transportation systems. The lockdown of the cities and the imposition of travel restrictions led to an ∼4–12 dB decrease in seismic noise power in mainland China. Data also show that different Chinese cities experienced distinct periods of diminished cultural noise, related to differences in local response to the epidemic. In contrast, there was only ∼1–6 dB decrease of seismic noise power in Italy, after the country was put under a lockdown. The noise data indicate that traffic flow did not decrease as much in Italy and show how different cities reacted distinctly to the lockdown conditions.

Temporal changes in anthropogenic seismic noise levels associated with economic and leisure activities during the COVID-19 pandemic

“…The weekday noise level strongly re ected the effects of the state of emergency, but the Sunday noise level likely re ected the concern of the people about the COVID-19 as most people continued to avoid non-essential outings even after emergency was lifted. Compared to other countries [12][13][14][15]24 , our results showed a higher reduction for the higher frequency range noise as MeSO-net stations are located in schools and the noise related to school activities is dominant. At frequencies <20 Hz, the reduction in the noise levels was unclear compared to those for higher frequencies because the number of stations that showed a high correlation coe cient was limited.…”

“…The large-scale restrictions on human activities during the pandemic also presented a rare opportunity to clearly distinguish anthropogenic seismic noise from ambient seismic noise. Poli et al 12 and Xiao et al 13 compared ambient seismic noise levels before and during the pandemic-related lockdown by using continuous seismic records for Italy and China, and observed a clear decrease in noise level during the lockdown. Poli et al 12 found that the noise level signi cantly reduced in the frequency band 1-10 Hz.…”

“…Xiao et al 13 inferred that this was caused by the difference in the strictness of enforcing restrictions by the governments of the two countries. Reduction of up to 50% in the noise level in the frequency range 4-14 Hz up to 50 % were observed world over 14 .…”

Global quieting of high-frequency seismic noise due to COVID-19 pandemic lockdown measures

“…Periods that are often seismically quiet include weekends, as well as the Christmas and New Year holidays for locations where they are celebrated. Notably, we found a near-global reduction in noise, commencing in China in late January 2020 (26), followed by Italy (26,27), the whole of Europe, and the rest of the world in March to April 2020. This period of reduced noise lasted longer and was often quieter than the Christmas-to-New Year period.…”

Effects of the COVID-19 Lockdown on Urban Light Emissions: Ground and Satellite Comparison

“…For example, this has been done for NO 2 concentrations in urban areas and globally for aerosol content (NASA, 2020a,b), noise (Bui and Badger, 2020), and seismic tremors (Xiao et al, 2020). Also, the impact of lockdown on night sky brightness in Berlin has been studied (Jechow and Hölker, 2020).…”