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Two-step Seismic Noise Reduction caused by COVID-19 Induced Reduction in Social Activity in metropolitan Tokyo, Japan
Suguru Yabe
National Institute of Advanced Industrial Science and Technology
Corresponding Author
ORCiD: https://orcid.org/0000-0002-5614-0198
License:
This work is licensed under a CC BY 4.0 License. Read Full License
View the published version at Earth, Planets and Space.
The COVID-19 pandemic that started at the end of 2019 forced populations around the world to reduce social and economic activities; it is believed that this can prevent the spread of the disease. In this paper, we report an analysis of the seismic noise during such an induced social activity reduction in the Tokyo metropolitan area, Japan. Using seismic data obtained from 18 stations in the Metropolitan Seismic Observation Network (MeSO-net), a two-step seismic noise reduction was observed during the timeline of COVID-19 in Tokyo. The first noise reduction occurred at the beginning of March 2020 in the frequency band of 20–40 Hz. This corresponded with the request by the Prime Minister of Japan for a nationwide shutdown of schools. Although social activity was not reduced significantly at this juncture, local reduction of seismic wave excitation in the high frequency band, 20–40 Hz, was recorded at some MeSO-net stations located in school properties. The second reduction of seismic noise occurred at the end of March to the beginning of April 2020 in a wider frequency band including lower frequency bands of 1–20 Hz. This timing corresponds to when the Governors of the Tokyo metropolitan area requested citizens to stay home and when the state of emergency was declared for the Tokyo metropolitan area by the government, respectively. Since then, the estimated population at train stations abruptly dropped, which suggests that social activity was severely reduced. Such large-scale changes in social activity affect the seismic noise level in low frequency bands. The seismic noise level started to increase from the middle of May correlating with increase in population at the train stations. This suggests that social activity restarted even before the state of emergency was lifted at the end of May. The two-step seismic noise reduction observed in this study has not been reported in other cities around the world. Unexpected reduction of social activity due to COVID-19 provided a rare opportunity to investigate the characteristics of seismic noise caused by human activities.
Keywords
Seismic noise, Cultural noise, COVID-19, Tokyo
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Figure 8
This is a list of supplementary files associated with this preprint. Click to download.
- FigS11.png
Figure S1. Average seismic noise level at the MeSO-net stations other than the four stations shown in Figure 4. Part 1
- FigS12.png
Figure S1. Average seismic noise level at the MeSO-net stations other than the four stations shown in Figure 4. Part 2
- FigS21.png
Figure S2. Noise ratio of UD components and polarization azimuth at the MeSO-net stations other than the four stations shown in Figure 7. Part 1
- FigS22.png
Figure S2. Noise ratio of UD components and polarization azimuth at the MeSO-net stations other than the four stations shown in Figure 7. Part 2
- FigS23.png
Figure S2. Noise ratio of UD components and polarization azimuth at the MeSO-net stations other than the four stations shown in Figure 7. Part 3
- FigS24.png
Figure S2. Noise ratio of UD components and polarization azimuth at the MeSO-net stations other than the four stations shown in Figure 7. Part 4
- FigS31.png
Figure S3. Median noise ratio during the day in two different frequency bands at the MeSO-net stations other than the four stations shown in Figure 8. Part 1
- FigS32.png
Figure S3. Median noise ratio during the day in two different frequency bands at the MeSO-net stations other than the four stations shown in Figure 8. Part 2
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This preprint is under consideration at Earth, Planets and Space. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Full paper
Two-step Seismic Noise Reduction caused by COVID-19 Induced Reduction in Social Activity in metropolitan Tokyo, Japan
Suguru Yabe
National Institute of Advanced Industrial Science and Technology
Corresponding Author
ORCiD: https://orcid.org/0000-0002-5614-0198
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Published
Version 3
Posted 12 Jan, 2021
Published
On 04 Nov, 2020
No community comments so far
Editor assigned
On 16 Oct, 2020
Editorial decision: Accept
On 16 Oct, 2020
Submission checks complete
On 15 Oct, 2020
Editor invited
On 15 Oct, 2020
No comments provided
Review #1 received
Received 07 Oct, 2020
Reviewers invited
Invitations sent on 25 Sep, 2020
Reviewer #1 agreed
On 25 Sep, 2020
Editor assigned
On 24 Sep, 2020
Submission checks complete
On 23 Sep, 2020
Editor invited
On 23 Sep, 2020
Version (no preprint)
Posted 24 Sep, 2020
Editor assigned
On 14 Oct, 2020
Submission checks complete
On 13 Oct, 2020
Editor invited
On 13 Oct, 2020
This version was not preprinted
No comments provided
Editorial decision: Minor Revision
On 31 Aug, 2020
Review #2 received
Received 30 Aug, 2020
Review #1 received
Received 20 Aug, 2020
Reviewer #2 agreed
On 08 Aug, 2020
Reviewer #1 agreed
On 30 Jul, 2020
Reviewers invited
Invitations sent on 29 Jul, 2020
Editor assigned
On 28 Jul, 2020
Editor invited
On 27 Jul, 2020
Submission checks complete
On 25 Jul, 2020
First submitted
On 23 Jul, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Planetary Geology
License:
This work is licensed under a CC BY 4.0 License. Read Full License
View the published version at Earth, Planets and Space.
The COVID-19 pandemic that started at the end of 2019 forced populations around the world to reduce social and economic activities; it is believed that this can prevent the spread of the disease. In this paper, we report an analysis of the seismic noise during such an induced social activity reduction in the Tokyo metropolitan area, Japan. Using seismic data obtained from 18 stations in the Metropolitan Seismic Observation Network (MeSO-net), a two-step seismic noise reduction was observed during the timeline of COVID-19 in Tokyo. The first noise reduction occurred at the beginning of March 2020 in the frequency band of 20–40 Hz. This corresponded with the request by the Prime Minister of Japan for a nationwide shutdown of schools. Although social activity was not reduced significantly at this juncture, local reduction of seismic wave excitation in the high frequency band, 20–40 Hz, was recorded at some MeSO-net stations located in school properties. The second reduction of seismic noise occurred at the end of March to the beginning of April 2020 in a wider frequency band including lower frequency bands of 1–20 Hz. This timing corresponds to when the Governors of the Tokyo metropolitan area requested citizens to stay home and when the state of emergency was declared for the Tokyo metropolitan area by the government, respectively. Since then, the estimated population at train stations abruptly dropped, which suggests that social activity was severely reduced. Such large-scale changes in social activity affect the seismic noise level in low frequency bands. The seismic noise level started to increase from the middle of May correlating with increase in population at the train stations. This suggests that social activity restarted even before the state of emergency was lifted at the end of May. The two-step seismic noise reduction observed in this study has not been reported in other cities around the world. Unexpected reduction of social activity due to COVID-19 provided a rare opportunity to investigate the characteristics of seismic noise caused by human activities.
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