Seismic Noise Characteristics at the Romanian Broadband Seismic Network

Grecu, Bogdan; Neagoe, Cristian; Tǎtaru, Dragoș

doi:10.1080/13632469.2011.642931

Cited by 8 publications

(6 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Above 1 Hz, the seismic noise is mainly generated by different human and industrial activities presenting a pronounced variability between daytime and nighttime, as well as between weekdays and weekends. This signature of anthropogenic origin on seismic noise at high frequencies has been investigated and recognized in many studies around the world (McNamara and Buland, 2004;Groos and Ritter, 2009;Diaz et al, 2010Diaz et al, , 2017Nakata et al, 2011;Grecu et al, 2018).…”

Section: Introductionmentioning

confidence: 87%

“…12 for two selected remote stations. The first one, station Cheia-Muntele Rosu (MLR), is part of the auxiliary seismic network of the International Monitoring System (IMS) installed in a vault in a remote setting and is one of the quietest seismic stations of RSN (Grecu et al, 2012). The noise reduction due to the lockdown is up to 24 % in Band 1 and 18 % in Band 2, respectively.…”

Section: Stations In Buildings Used For Structural Monitoringmentioning

confidence: 99%

“…The latter has different origins and specific characteristics, depending on the frequency band in which it is recorded. At low frequencies (0.05-0.5 Hz), seismic noise has a natural origin linked to oceanic activities (Longuet-Higgins, 1950;Hasselmann, 1963) and exhibits strong seasonal variations (McNamara and Buland, 2004;Marzorati and Bindi, 2006;Diaz et al, 2010;Evangelidis and Melis, 2012;Grecu et al, 2012). Above 1 Hz, the seismic noise is mainly generated by different human and industrial activities presenting a pronounced variability between daytime and nighttime, as well as between weekdays and weekends.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The effect of 2020 COVID-19 lockdown measures on seismic noise recorded in Romania

et al. 2021

Self Cite

View full text Add to dashboard Cite

Abstract. After the World Health Organization declared COVID-19 a pandemic in March 2020, Romania followed the example of many other countries and imposed a series of restrictive measures, including restricting people's mobility and closing social, cultural, and industrial activities to prevent the spread of the disease. In this study, we analyze continuous vertical component recordings from the stations of the Romanian Seismic Network – one of the largest networks in Europe, consisting of 148 stations – to explore the seismic noise variation associated with the reduced human mobility and activity due to the Romanian measures against COVID-19 in detail. We focused our investigation on four frequency bands – 2–8, 4–14, 15–25 and 25–40 Hz – and found that the largest reductions in seismic noise associated with the lockdown correspond to the high-frequency range of 15–40 Hz. We found that all the stations with large reductions in seismic noise (>∼ 40 %) are located inside and near schools or in buildings, indicating that at these frequencies the drop is related to the drastic reduction of human activity in these edifices. In the lower-frequency range (2–8 and 4–14 Hz) the variability of the noise reduction among the stations is lower than in the high-frequency range, corresponding to about 35 % on average. This drop is due to reduced traffic during the lockdown, as most of the stations showing such changes in seismic noise in these bands are located within cities and near main or side streets. In addition to the noise reduction observed at stations located in populated areas, we also found seismic noise lockdown-related changes at several stations located far from urban areas, with movement of people in the vicinity of the station explaining the noise reductions.

show abstract

Section: Introductionmentioning

confidence: 87%

Section: Stations In Buildings Used For Structural Monitoringmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The effect of 2020 COVID-19 lockdown measures on seismic noise recorded in Romania

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…The long-term evolution of the DRMS is shown in Figure 12 for two selected remote stations. The first one, station Cheia-Muntele Rosu (MLR), is part of the auxiliary seismic network of the International Monitoring System (IMS) installed in a vault in a remote setting and is one of the quietest seismic stations of RSN (Grecu et al, 2012). The noise reduction due to the lockdown is up to 24% in Band 1 and 18% in Band 2, respectively.…”

Section: Stations In Less Populated Areasmentioning

confidence: 99%

The effect of 2020 COVID-19 lockdown measures on seismic noise recorded in Romania

Grecu¹,

Borleanu²,

Tiganescu³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. After the World Health Organization declared COVID-19 a pandemic in March 2019, Romania followed the example of many other countries and imposed a series of restrictive measures, including restricting people's mobility and closing social, cultural and industrial activities to prevent the spread of the disease. In this study, we analyze continuous vertical component recordings from the stations of the Romanian Seismic Network – one of the largest networks in Europe containing 148 stations – to explore in detail the seismic noise variation associated with the reduced human mobility and activity in Romania due to COVID-19. We focused our investigation on four frequency bands – 2–8 Hz, 4–14 Hz, 15–25 Hz and 25–40 Hz – and found that the largest reductions in seismic noise associated with the lockdown corresponds to the high frequency range, from 15 to 40 Hz. We found that all the stations with large reductions in seismic noise (> ~40 %) are located inside and near schools or in buildings, indicating that at these frequencies the drop is related to the drastic reduction of human activity in these edificies. In the lower frequency range (2–8 Hz and 4–14 Hz) the variability of the noise reduction among the stations is lower than in the high frequency range, and the noise level is reduced by up to 35 %. This drop is due to reduced traffic during the lockdown, as most of the stations showing such changes in seismic noise in these bands are located within cities, near main or side streets. In addition to the noise reduction observed at stations located in populated areas, we also found seismic noise lockdown-related changes at several stations located far from urban areas, with movement of people in the vicinity of the station explaining the noise reductions. Apart from the opportunity to investigate in more detail the seismic noise characteristics due to human mobility and activity, we show that noise reduction during the lockdown has also improved the earthquake detection capability of the accelerometers located in noisy urban environments.

show abstract

“…The proposed methodology is useful to characterize network performance, to detect problems with stations (instrumental and/or related to site conditions), and to prioritize network interventions. The approach proposed by McNamara and Buland (2004) had the advantage of using continuous data and being thoroughly documented and has since been adopted around the world (e.g., Marzorati and Bindi, 2006;Sheen et al, 2009;Evangelidis and Melis, 2012;Grecu et al, 2012;Rastin et al, 2012). The most common main results of the studies listed above include: (1) cultural/ anthropogenic sources significantly affect seismic noise at short-period (SP), which often displays strong diurnal variations; (2) microseismic noise (3-20 s) is strongly affected by seasonal variations and in general is well correlated with oceanic conditions; (3) long-period (LP) seismic noise is often affected by the type of installation and insulation from environmental conditions.…”

Section: Introductionmentioning

confidence: 99%

Ambient Noise Recorded by a Dense Broadband Seismic Deployment in Western Iberia

Custódio¹,

Dias²,

Caldeira³

et al. 2014

Bulletin of the Seismological Society of America

View full text Add to dashboard Cite

The West Iberia Lithosphere and Asthenosphere Structure (WILAS) project densely covered Portugal with broadband seismic stations for 2 yrs. Here we provide an overview of the deployment, and we characterize the network ambient noise and its sources. After explaining quality control, which includes the assessment of sensor orientation, we characterize the background noise in the short-period (SP), microseismic, and long-period (LP) bands. We observe daily variations of SP noise associated with anthropogenic activity. Temporary and permanent stations present very similar noise levels at all periods, except at horizontal LPs, where temporary stations record higher noise levels. We find that median noise levels are extremely homogeneous across the network in the microseismic band (3-20 s) but vary widely outside this range. The amplitudes of microseismic noise display a strong seasonal variation. The seasonality is dominated by very-long-period double-frequency microseisms (8 s), probably associated with winter storms. Stacks of ambient noise amplitudes show that some microseismic noise peaks are visible across the whole ground-motion spectrum, from 0.3 to 100 s. Periods of increased microseismic amplitudes generally correlate with ocean conditions offshore of Portugal. Some seismic records display an interesting 12 hr cycle of LP (100-s) noise, which might be related to atmospheric tides. Finally, we use plots of power spectral density versus time to monitor changes in LP instrumental response. The method allows the identification of the exact times at which LP response changes occur, which is required to improve the understanding of this instrumental artifact and to eventually correct data.

show abstract

Seismic Noise Characteristics at the Romanian Broadband Seismic Network

Cited by 8 publications

References 13 publications

The effect of 2020 COVID-19 lockdown measures on seismic noise recorded in Romania

The effect of 2020 COVID-19 lockdown measures on seismic noise recorded in Romania

The effect of 2020 COVID-19 lockdown measures on seismic noise recorded in Romania

Ambient Noise Recorded by a Dense Broadband Seismic Deployment in Western Iberia

Contact Info

Product

Resources

About