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. 2017 Nov 10;7:15296. doi: 10.1038/s41598-017-15499-y

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© The Author(s) 2017

Open Access 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 http://creativecommons.org/licenses/by/4.0/.

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Spectrogram of the vertical seismic acceleration during the time interval 01/9/2016–13/9/2016. Red box shows the frequency range dominated by ocean activity, blue box shows the band dominated by traffic and green boxes show the low frequency (continuous line) and high frequency (dashed line) bands associated to subway activity. Week-ends are shown by bold dates. Color scale is expressed in dB referred to 1 (m²/s⁴)/Hz.