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Ground vibrations recorded by fiber-optic cables reveal traffic response to COVID-19 lockdown measures in Pasadena, California

Wang, Xin and Zhan, Zhongwen and Williams, Ethan F. and González Herráez, Miguel and Martins, Hugo Fidalgo and Karrenbach, Martin (2021) Ground vibrations recorded by fiber-optic cables reveal traffic response to COVID-19 lockdown measures in Pasadena, California. Communications Earth & Environment, 2 (1). Art. No. 160. ISSN 2662-4435. doi:10.1038/s43247-021-00234-3.

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The COVID-19 lockdown has unprecedently affected the dynamics of our society. As traffic flow is a good proxy for societal activity, traffic monitoring becomes a useful tool to assess the lockdown’s impacts. Here we turned two strands of unused telecommunication fibers in Pasadena, California into a seismic array of ~5,000 sensors and detected ground vibrations caused by moving vehicles along the streets above the cable. We monitor the number of vehicles and their mean speed between December 2019 and August 2020 in high spatial and temporal resolution, and then analyze the traffic patterns change due to the COVID-19 lockdown. Our results show a city-wide decline in traffic volume and an increase in speed due to the lockdown, although the level of impact varies substantially by streets. This study demonstrates the feasibility of using telecommunication fiber optic cables in traffic monitoring, which has implications for public health, economy, and transportation safety.

Item Type:Article
Related URLs:
URLURL TypeDescription ReadCube access
Wang, Xin0000-0002-6180-0058
Zhan, Zhongwen0000-0002-5586-2607
Williams, Ethan F.0000-0002-7917-4104
González Herráez, Miguel0000-0003-2555-2971
Martins, Hugo Fidalgo0000-0003-3927-8125
Karrenbach, Martin0000-0003-2190-8598
Additional Information:© The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit Received 12 April 2021; Accepted 23 July 2021; Published 11 August 2021. We thank the City of Pasadena for contributing its fiber optic cables to our research. The DAS instruments used in this study were provided by the OptaSense, University of Alcala, and Aragon Photonics. We thank Lisa LaFlame, Victor Yartsev, Steve Cole, and Vlad Bogdanov for their assistance in acquiring the data used in this study. We are grateful for numerous discussions with people in the Department of Transportation, Pasadena. We are also grateful to the editor, reviewer Yunyue Elita Li, and two anonymous reviewers for their suggestions and comments, which help improve the quality of this paper. This work is supported by NSF CAREER award #1848166; the Young Elite Scientists Sponsorship Program by CAST (grant 2020QNRC001); the Key Research Program of the Institute of Geology & Geophysics, CAS (grant IGGCAS-201904); the Spanish MICINN (RTI2018-097957-B-C31, RTI2018-097957-B-C33); the European Research Council (OCEAN-DAS: ERC-2019-POC-875302). The work of HFM was supported by MINECO (“Juan de la Cierva” postdoc contract IJCI-2017-33856). Data availability: The obtained traffic data (in MATLAB format, a MATLAB script is also provided to load and plot the data) in this study can be downloaded from CaltechDATA achieve at Code availability: The codes used in this study are available from Dr. Xin Wang ( upon reasonable request. Author Contributions: X.W. and Z.Z. conceived the main ideas, led the project, and wrote the initial draft of the paper. X.W., Z.Z., E.F.W., M.G.H., H.F.M. and M.K. discussed the results and contributed to the writing of the final paper. The authors declare no competing interests. Peer review information: Communications Earth & Environment Materials thanks Yunyue Elita Li, Siyuan Yuan and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editors: Clare Davis.
Group:COVID-19, Seismological Laboratory
Funding AgencyGrant Number
China Association for Science and Technology2020QNRC001
Chinese Academy of SciencesIGGCAS-201904
Ministerio de Ciencia e Innovación (MCINN)RTI2018-097957-B-C31
Ministerio de Ciencia e Innovación (MCINN)RTI2018-097957-B-C33
European Research Council (ERC)875302
Ministerio de Economía, Industria y Competitividad (MINECO)IJCI-2017-33856
Subject Keywords:Environmental impact; Environmental studies; Seismology
Issue or Number:1
Record Number:CaltechAUTHORS:20210812-141727237
Persistent URL:
Official Citation:Wang, X., Zhan, Z., Williams, E.F. et al. Ground vibrations recorded by fiber-optic cables reveal traffic response to COVID-19 lockdown measures in Pasadena, California. Commun Earth Environ 2, 160 (2021).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110223
Deposited By: Tony Diaz
Deposited On:12 Aug 2021 16:18
Last Modified:12 Aug 2021 16:18

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