Reliability of Ambient Noise Horizontal-to-Vertical Spectral Ratio in Urban Environments: The Case of Thessaloniki City (Northern Greece)

Panou, Areti; Theodulidis, N.; Hatzidimitriou, P. M.; Savvaidis, Alexandros; Papazachos, C. B.

doi:10.1007/s00024-004-2647-6

Cited by 32 publications

(20 citation statements)

References 44 publications

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“…The study area reflects a high variability in terms of fundamental frequency f 0 and alluvium thickness H. Overall results reflect low values of fundamental frequency (f 0 ) and corresponding greater values of alluvium thickness (H), thus indicating a greater seismic risk triggered by soil amplification in the study area. The findings of the study showed complete agreement with the research studies conducted by Field and Jacob (1995), Lachet et al (1996), Parolai et al (2002), and Panou et al (2005), (Bala et al 2007a, b).…”

Section: Discussionsupporting

confidence: 90%

“…Many scientists such as Chávez-García et al (1990, Bard (1999), Bour et al (1998) have utilized H/V and proven the reliability and credibility of this technique. H/V method is a very reliable method for estimating alluvium thickness by means of fundamental frequencies of the soft sediments (Morales et al 1991;Yamanaka et al 1994;Parolai et al 2002;Panou et al 2005). Contrary to the fundamental frequency f 0 , amplification factor A 0 reveals disagreement between opinions and findings of different scientists.…”

Section: Introductionmentioning

confidence: 99%

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Ambient noise H/V spectral ratio in site effects estimation in Fateh jang area, Pakistan

et al. 2015

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Local geology or local site effect is a crucial component while conducting seismic risk assessment studies. Investigations made by utilization of ambient noise are an effective tool for local site estimation. The present study is conducted to perform site response analysis at 13 different sites within urban settlements of Fateh jang area (Pakistan). The aim of this study was achieved by utilizing Nakamura method or H/V spectral ratio method. Some important local site parameters, e.g., the fundamental frequencies f 0 of soft sediments, amplitudes A 0 of corresponding H/V spectral ratios, and alluvium thicknesses over 13 sites within the study area, were measured and analyzed. The results show that the study area reflects low fundamental frequency f 0 . The fundamental frequencies of the sediments are highly variable and lie in a range of 0.6-13.0 Hz. Similarly, amplification factors at these sites are in the range of 2.0-4.0.

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Ambient noise H/V spectral ratio in site effects estimation in Fateh jang area, Pakistan

et al. 2015

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“…In contrast, and as reported in various other studies (e.g. Parolai et al 2004;Panou et al 2005;Guillier et al 2007), the shape and amplitude of the H/V curves remains fairly constant.…”

Section: Amplitude Spectrasupporting

confidence: 74%

“…This has also been observed during longer-term deployments of single stations for H/V measurements (Parolai et al 2004;Panou et al 2005;Guillier et al 2007). Nevertheless, consistent with the findings in this study, the derived H/V peak frequencies are reported to be stable with time.…”

Section: Amplitude Spectrasupporting

confidence: 56%

On the repeatability and consistency of three-component ambient vibration array measurements

Endrun

Ohrnberger

Savvaidis

2009

Bull Earthquake Eng

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Ambient vibration measurements with small, temporary arrays that produce estimates of surface wave dispersion have become increasingly popular as a low-cost, noninvasive tool for site characterisation. An important requirement for these measurements to be meaningful, however, is the temporal consistency and repeatability of the resulting dispersion and spatial autocorrelation curve estimates. Data acquired within several European research projects (NERIES task JRA4, SESAME, and other multinational experiments) offer the chance to investigate the variability of the derived data products. The dataset analysed here consists of repeated array measurements, with several years of time elapsed between them. The measurements were conducted by different groups in different seasons, using different instrumentations and array layouts, at six sites in Greece and Italy. Ambient vibration amplitude spectra and locations of dominant sources vary between the two measurements at each location. Still, analysis indicates that this does not influence the derived dispersion information, which is stable in time and neither influenced by the instrumentation nor the analyst. The frequency range over which the dispersion curves and spatial autocorrelation curves can be reliably estimated depends on the array dimensions (minimum and maximum aperture) used in the specific deployment, though, and may accordingly vary between the repeated experiments. The relative contribution of Rayleigh and Love waves to the wavefield can likewise change between repeated measurements. The observed relative contribution of Rayleigh waves is generally at or below 50%, with especially low values for the rural sites. Besides, the visibility of higher modes depends on the noise wavefield conditions. The similarity of the dispersion and autocorrelation curves measured at each site indicates B. Endrun (B) · M. Ohrnberger 123 536 Bull Earthquake Eng (2010) 8:535-570 that the curves are stable, mainly determined by the sub-surface structure, and can thus be used to derive velocity information with depth. Differences between velocity models for the same site derived from independently determined dispersion and autocorrelation curves-as observed in other studies-are consequently not adequately explained by uncertainties in the measurement part.

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“…In addition, variations in the relative content of Love and Rayleigh waves could explain the observed temporal variations in measured H/V amplitudes (e.g. Panou et al, 2005b). …”

Section: Introductionmentioning

confidence: 98%

Love wave contribution to the ambient vibration H/V amplitude peak observed with array measurements

Endrun

2010

J Seismol

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To cite this version:Brigitte Endrun. Love wave contribution to the ambient vibration H/V amplitude peak observed with array measurements. Journal of Seismology, Springer Verlag, 2010, 15 (3) Abstract: This study applies array methods to measure the relative proportions of Love and Rayleigh waves in the ambient vibration wavefield. Information on these properties is of special relevance for frequencies around the horizontal-to-vertical (H/V) spectral amplitude ratio peak. The analysis of H/V curves, a popular technique in site characterisation, commonly assumes that the curves represent the frequency-dependent Rayleigh wave ellipticity. For the detailed interpretation of amplitudes or the inversion of the curves, it is therefore necessary to estimate and correct for the contribution of other wave types to the ambient vibration wavefield. I use available ambient vibration array measurements to determine the relative amount of Love and Rayleigh waves on the horizontal components by frequency-dependent analysis of the main propagation and polarisation directions, with a special emphasis on the H/V peak frequency as determined from the same recordings. Tests with synthetic data demonstrate the feasibility of this approach, at least in the presence of dominant source regions. Analysis of the data from 12 measurements at nine European sites, which include shallow as well as deep locations that span a wide range of impedance contrasts at the sediment-bedrock interface, indicates that the relative contribution of Rayleigh waves varies widely with frequency, from close to 0\% to more than 70\%. While most data sets show relative Rayleigh wave contributions between 40\% and 50\% around the H/V peak, there are also examples where Love waves clearly dominate the wavefield at the H/V peak, even for a site with a low impedance contrast. Longer-term measurements at one site indicate temporal variations in the relative Rayleigh wave content between day-and nighttime. Results calculated with the method introduced herein generally compare well with results of modified spatial autocorrelation analysis. These two methods might be used in a complimentary fashion, as both rely on different properties of the ambient vibration wavefield. This study illustrates that it is possible to measure the relative Rayleigh wave content of the noise wavefield from array data. Furthermore, the examples presented herein indicate it is important to estimate this property, as the assumption that there are an equal proportion of Love and Rayleigh waves is not always correct.Response to Reviewers: Please refer to the uploaded PDF file ResponsetoReviewersJOSE405.pdf Abstract This study applies array methods to measure the relative proportions of Love and Rayleigh waves in the ambient vibration wavefield. Information on these properties is of special relevance for frequencies around the horizontalto-vertical (H/V) spectral amplitude ratio peak. The analysis of H/V curves, a popular technique in site characterisation, commonly assumes that the curves repre...

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Reliability of Ambient Noise Horizontal-to-Vertical Spectral Ratio in Urban Environments: The Case of Thessaloniki City (Northern Greece)

Cited by 32 publications

References 44 publications

Ambient noise H/V spectral ratio in site effects estimation in Fateh jang area, Pakistan

Ambient noise H/V spectral ratio in site effects estimation in Fateh jang area, Pakistan

On the repeatability and consistency of three-component ambient vibration array measurements

Love wave contribution to the ambient vibration H/V amplitude peak observed with array measurements

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