Seismometers Within Cities: A Tool to Connect Earth Sciences and Society

Abstract

The high degree of human activities in urban environments produces large background vibrations that makes it difficult to use data acquired in these areas for classical seismology. Seismometers installed within cities have been typically been used for the study of seismic hazard or for monitoring civil engineering problems. However, with the development of monitoring techniques based on the interpretation of the so-called seismic ambient noise, these data have gained scientific interest. Our objective is to discuss an additional utility of seismometers deployed within a city; its use as a tool to connect society with Earth sciences. Many citizen activities, from traffic to music concerts, produce vibrations that can be recorded seismically, and our experience shows that these records attract the attention of the media and social networks. With the emergence of low-cost and easy-to-use instruments in recent years, more citizens can now record ground motion and become interested in the interpretation of the recorded seismograms. The installation of permanent seismic networks in educational centers has proven to be a good approach to introduce students to Earth sciences at the national level and can also be developed at the urban scale using this new instrumentation. In this contribution we will first review the previous results related to the identification of the sources of vibration in urban areas and then present a new ongoing project based on the deployment of a seismic network in educational centers located in the city of Barcelona.

Sensing earth and environment dynamics by telecommunication fiber-optic sensors: An urban experiment in Pennsylvania USA

“…Figure 11 shows significant peaks at around 2.0 Hz and 4.0 Hz (harmonic), while they disappear at midnight. This 2.0 Hz signal corresponds to walking steps on campus, equivalent to 120 steps per minute, which is similar to the people walking on shopping floors with an average frequency of 2.0 Hz and a velocity of 1.4 m/s (Pachi and Ji, 2005), slower than marathon runners with 2.8 Hz (Diaz et al, 2020). Not surprisingly, this footstep signals are not shown up on April 16 2020 during the COVID-19 crisis after the stay-at-home order in PA on April 1 2020.…”

Using Seismic Noise Levels to Monitor Social Isolation: An Example From Rio de Janeiro, Brazil

“…The noise recorded by seismic stations near or within a city, at frequencies above 1 Hz, is commonly interpreted as due mainly to anthropogenic sources. The significant decrease in noise levels during the COVID‐19 lockdown has enabled a clear determination that the “cultural noise” spans the frequency range of 1–40 Hz, but mostly between 2 and 20 Hz (Díaz et al, 2020; Poli et al, 2020). Poli et al (2020) showed that different cities have different spectra of anthropogenic noise, depending on the type of sources in the vicinity of the station.…”

“…At long periods (1 to 50 s) it is mainly produced by atmospheric oscillations and ocean waves, with ocean waves giving energy peaks around 5 and 10 s (e.g., Bormann, 2002; Juretzek & Hadziioannou, 2016; Yang & Ritzwoller, 2008). At high frequencies, above a 1 Hz, it is mainly produced by local perturbations, both natural, such as wind and storms, and anthropogenic, such as vehicles and factories (e.g., Díaz et al, 2020; Poli et al, 2020).…”

COVID-19 lockdown and its latency in Northern Italy: seismic evidence and socio-economic interpretation

“…As seismic monitoring networks operate continuously, seismic data can be easily used to track changes in the ambient noise. This approach is effective in providing insights on the variation of natural and anthropogenic noise sources 4 , in seasonality of waves and winds 5 , and on the effect of disruptive events like the Super Typhoon Ioke 6 . The observation of the anthropogenic noise at high frequency (F > 1 Hz) dates back to the 60′s 7 and, especially in regions with high anthropic activity and poor rock characterization like a large portion of our study area (i.e.…”

“…3 Department of Economics and Management, University of Ferrara, Via Voltapaletto 11, 44121 Ferrara, Italy. 4 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, Via di Vigna Murata 605, 00143 Rome, Italy. * email: davide.piccinini@ingv.it the causes for the observed spatial and temporal fluctuations in noise reduction with the goal of understanding how they originated.…”