Preprints
https://doi.org/10.5194/se-2020-200
https://doi.org/10.5194/se-2020-200

  11 Dec 2020

11 Dec 2020

Review status: a revised version of this preprint was accepted for the journal SE and is expected to appear here in due course.

Seismic noise variability as an indicator of urban mobility during COVID-19 pandemic in Santiago Metropolitan Region, Chile

Javier Ojeda and Sergio Ruiz Javier Ojeda and Sergio Ruiz
  • Departmento de Geofísica, Universidad de Chile, Santiago, Chile

Abstract. On 3 March 2020, the first case of COVID-19 was confirmed in Chile. Since then, the Ministry of Health has imposed mobility restrictions, a global policy implemented to mitigate the propagation of the virus. The national seismic network operating throughout Chile provides an opportunity to monitor the ambient seismic noise (ASN) and determine the effectiveness of public policies imposed to reduce urban mobility in the major cities. Herein, we analyse temporal variations in high-frequency ASN recorded by broadband and strong-motion instruments deployed throughout the main cities of Chile. We focus on the capital, Santiago, a city with more than 7 million inhabitants, because it is seismically well-instrumented, and has high levels of urban mobility due to work commutes inside the region. We observed strong similarities between anthropogenic seismic noise and human mobility indicators, as shown in the difference between urban and rural amplitudes, long-term variations, and variability due to the COVID-19 outbreak. Our findings suggest that the initially implemented public health policies and the early deconfinement in mid-April 2020 in the metropolitan region caused an increase in mobility and virus transmission, where the peak in anthropogenic seismic noise coincides with the peak of the effective reproductive number from confirmed positive cases of COVID-19. These results confirm that seismic networks are capable of monitoring the urban mobility of population within cities, and we show that continuous monitoring of ASN can quantify urban mobility. Finally, we suggest to consider monitoring in real time the changes in ASN amplitudes to be included in the public policies about urban mobilities in Santiago as well as other high density cities of the world, as has been useful during the recent pandemic.

Javier Ojeda and Sergio Ruiz

 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
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Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Javier Ojeda and Sergio Ruiz

Javier Ojeda and Sergio Ruiz

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Short summary
In Santiago, Chile, the lockdown imposed due to COVID-19 was recorded by seismological instruments. The analysis shows temporal changes in the surface vibrations controlled by lockdown phases, urban mobility, and epidemiological factors. Our findings suggest that dynamic lockdown and the early deconfinement in April 2020 caused an increase in mobility and therefore virus transmission. We propose that seismic networks could be used to monitor urban mobility, as a new proxy in public policies.