Ambient noise horizontal-to-vertical spectral ratio in site effects estimation and correlation with seismic damage distribution in urban environment: the case of the city of Thessaloniki (Northern Greece)

2005 ◽  
Vol 25 (4) ◽  
pp. 261-274 ◽  
Author(s):  
A.A. Panou ◽  
N. Theodulidis ◽  
P. Hatzidimitriou ◽  
K. Stylianidis ◽  
C.B. Papazachos
Keyword(s):  
Urban Environment ◽  
Site Effects ◽  
Ambient Noise ◽  
Spectral Ratio ◽  
Seismic Damage ◽  
Damage Distribution ◽  
Northern Greece ◽  
The City

scholarly journals AMBIENT NOISE HORIZONTAL-TO-VERTICAL SPECTRAL RATIO FOR ASSESSING SITE EFFECTS IN URBAN ENVIRONMENTS: THE CASE OF THESSALONIKI CITY ( NORTHERN GREECE )

2004 ◽  
Vol 36 (3) ◽  
pp. 1467 ◽  
Author(s):  
A. A. Panou ◽  
N. Theodulidis ◽  
P. M. Hatzidimitriou ◽  
C. B. Papazachos ◽  
K. Stylianidis
Keyword(s):  
Fundamental Frequency ◽  
Ambient Noise ◽  
Spectral Ratio ◽  
Urban Environments ◽  
Macroseismic Data ◽  
Northern Greece ◽  
Contour Maps ◽  
Noise Measurements ◽  
The City ◽  
Amplitude Level

250 ambient noise measurements were performed in a dense grid (about 150mX150m) covering the historical center of the city of Thessaloniki (Northern Greece), that was strongly affected by the 20/6/1978 (M=6.5) damaging earthquake. The data were processed using the method of horizontal- to-vertical (H/V) spectral ratio (Nogoshi and Igarashi, 1971; Nakamura, 1989). In order to evaluate diurnal and seasonal variation (summer - winter) of the ambient noise H/V spectral ratio, systematic measurements were performed in eight sites. The fundamental frequency (fo) and the corresponding H/V amplitude level (Ao) from the ambient noise H/V spectral ratio for each site were calculated. Spatial interpolation of the fundamental frequency (fo) and the corresponding H/V amplitude level (Ao) was attempted between all points and respective contour maps were produced. Diurnal variation of the ambient noise H/V spectral ratio showed that it is preferable to perform measurements during the calm hours of a day, when manmade noise is relatively low. However, no systematic seasonal fluctuation effect on the ambient noise H/V spectral ratio was identified for the city of Thessaloniki. Contour maps of both fundamental frequency (fo) and corresponding H/V amplitude level (Ao) were compared versus the macroseismic data of the 1978 earthquake (Leventakis, 2003), as well as with related geological (IGME, 1978) and geotechnical (Anastasiadis et al., 2001) studies for the same area. Damage distribution due to 20/6/1978 earthquake (Penelis et al., 1985) was also converted to EMS_98 (European Macroseismic Scale, 1998). For seventy buildings, made of reinforced concrete, we have also compared the obtained results with the dynamic amplification of the buildings (Ubuilding) at the fundamental soil frequency (fo). The results encourage the use of ambient noise measurements along with the (H/V) spectral ratio technique as a nonexpensive and fast tool in microzonation studies to be carried out in urban environments.

The 1983 Liege Earthquake: Damage Distribution and Site Effects

1990 ◽  
Vol 6 (4) ◽  
pp. 713-737 ◽  
Author(s):  
D. Jongmans ◽  
M. Campillo
Keyword(s):  
Site Effects ◽  
Large Scale ◽  
Site Response ◽  
Dominant Frequency ◽  
Small Scale ◽  
Eastern United States ◽  
Frequency Range ◽  
Damage Distribution ◽  
Damage Data ◽  
The City

On November 8, 1983, a moderate magnitude (Ml=4.9) earthquake struck Liege (Belgium). A damage study has shown that site effects at different scales have played an important role in amplifying ground motion. On a large scale, the damage distribution has been determined by the presence of a large Carboniferous syncline beneath the city as shown by 2D numerical modeling. On a small scale, the main damage concentrations can be correlated with local superficial deposits which have amplified ground motions in the frequency range of buildings. A geophysical survey was carried out to measure the shear wave velocity of the different formations. Site response computations were made at numerous sites in order to estimate the possible amplification and to compare the results with the damage. It was shown that the spectral amplifications computed in the dominant frequency range of the buildings are consistent with the damage data. In very affected areas, 1D amplifications of 4 to 6 were obtained and in some cases 2D effects may have occurred. The Liege earthquake, taking place in the intraplate region of Northwestern Europe, presents a significant interest to other similar areas as the eastern United States.

Correlation between damage distribution and ambient noise H/V spectral ratio: the SESAME project results

2008 ◽  
Vol 6 (1) ◽  
pp. 109-140 ◽  
Author(s):  
Nikolaos Theodoulidis ◽  
Giovanna Cultrera ◽  
Valerio De Rubeis ◽  
Fabrizio Cara ◽  
Areti Panou ◽  
...  
Keyword(s):  
Ambient Noise ◽  
Spectral Ratio ◽  
Damage Distribution

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

2015 ◽  
Vol 28 (1) ◽  
pp. 87-95 ◽  
Author(s):  
S. M. Talha Qadri ◽  
Bushra Nawaz ◽  
S. H. Sajjad ◽  
Riaz Ahmad Sheikh
Keyword(s):  
Site Effects ◽  
Ambient Noise ◽  
Spectral Ratio

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

2005 ◽  
Vol 162 (5) ◽  
pp. 891-912 ◽  
Author(s):  
A. A. Panou ◽  
N.P. Theodulidis ◽  
P.M. Hatzidimitriou ◽  
A.S. Savvaidis ◽  
C.B. Papazachos
Keyword(s):  
Ambient Noise ◽  
Spectral Ratio ◽  
Urban Environments ◽  
Northern Greece

scholarly journals Combining recordings of earthquake ground-motion and ambient vibration analysis to estimate site response variability in the city of Lucerne, Switzerland

2021 ◽  
Author(s):  
Paulina Janusz ◽  
Vincent Perron ◽  
Christoph Knellwolf ◽  
Walter Imperatori ◽  
Luis Fabian Bonilla ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Urban Areas ◽  
Ambient Noise ◽  
Site Response ◽  
Spectral Ratio ◽  
Response Variability ◽  
Standard Spectral Ratio ◽  
Hazard And Risk ◽  
The City

<p>Estimation of site effects is an essential part of local seismic hazard and risk assessment, especially in densely populated urban areas. The goal of this study is to assess the site response variability in the city of Lucerne (Central Switzerland), located in a basin filled with unconsolidated deposits. Even though it is a low-to-moderate seismicity area, the long-term seismic risk cannot be neglected, in particular, because the region was struck by strong earthquakes in the past (i.e. Mw 5.9 in 1601).</p><p>To determine the spatial distribution of the soil response in the test area, we combined earthquake and ambient noise recordings using the Hybrid Standard Spectral Ratio method (SSRh) introduced by Perron et al. (2018). In the first step, we installed a temporary seismic network to record ground-motion from low-magnitude or distant earthquakes. At selected urban sites inside the sedimentary basin, the dataset was used to estimate the amplification factors with respect to a rock site using the Standard Spectral Ratio approach (SSR - Borcherdt, 1970). Then, a survey including several dozens of densely distributed single-station ambient noise measurements was performed which enabled us to estimate the basin response variability relative to the seismic stations of the temporary seismic network. Finally, we corrected the noise-based evaluation using the SSR amplification functions. To verify the useability of the presented technique in the Lucerne area, we applied the SSRh method also to the temporary stations, the resulting amplification functions largely coincide with the SSR curves. However, the daily variability of the noise wavefield due to human activities can slightly affect the results. We will also discuss the influence of the station distribution and density of the temporary network deployment.</p><p>The amplification model for the Lucerne area estimated using the SSRh method shows consistency with geological data. The results indicate that seismic waves can be amplified up to 10 times in some parts of the basin compared to the rock site. The highest amplification factors are observed for frequencies between 0.8 and 2Hz. This means a local significant increase in seismic hazard.</p><p>The presented work is a part of a detailed site response analysis study for the Lucerne area, considering 2D and 3D site effects and potential non-linear soil behaviour. This PhD project is performed in the framework of the Horizon 2020 ITN funded project URBASIS-EU, which focuses on seismic hazard and risk in urban areas.</p><p>REFERENCES</p><p>Borcherdt, R.D., 1970. Effects of local geology on ground motion near San Francisco Bay. Bull. Seismol. Soc. Am. 60, 29–61.</p><p>Perron, V., Gélis, C., Froment, B., Hollender, F., Bard, P.-Y., Cultrera, G., Cushing, E.M., 2018. Can broad-band earthquake site responses be predicted by the ambient noise spectral ratio? Insight from observations at two sedimentary basins. Geophys. J. Int. 215, 1442–1454.</p>

Non-stability of the noise HVSR at sites near or on topographic heights

2020 ◽  
Vol 222 (3) ◽  
pp. 2162-2171
Author(s):  
M La Rocca ◽  
G D Chiappetta ◽  
A Gervasi ◽  
R L Festa
Keyword(s):  
Background Noise ◽  
Seismic Noise ◽  
Site Effects ◽  
Ambient Noise ◽  
Spectral Ratio ◽  
Topographic Effects ◽  
Tyrrhenian Sea ◽  
Horizontal Ground Motion ◽  
Bad Weather ◽  
Stable Feature

SUMMARY The horizontal to vertical spectral ratio (HVSR) of seismic noise is often used to investigate site effects, and it is usually assumed to be a stable feature of the site considered. Here we show that such an assumption is not always justified, and may lead to incorrect conclusions. The HVSR analysis was performed on ambient seismic noise recordings lasting from weeks to months at many sites in Calabria, Italy. Results show a variety of site effects, from the resonance of a shallow sedimentary layer to the polarized amplification of horizontal ground motion associated with topographic effects. We describe the results of seven sites whose HVSR is characterized by dual content: one that is persistent, and another appearing only occasionally. Two sites very near the coast of the Tyrrhenian sea and five sites in the Calabrian Arc mountains show the most remarkable results. The shape of the HVSR changes significantly at these sites when the amplitude of background noise increases in a broad frequency band during periods of bad weather. The occasional contribution to the HVSR consists of one or more peaks, depending on the site, that appear only when the amplitude of ambient noise is higher than usual. The seven sites where we observe the HVSR variability are all located in complex geological environments, on mountains, ridges or foothills. A variation of the HVSR correlated with the day–night cycle is also observed at some of these sites.

Concerning the Concept of Light-Colour Arrangement of the Urban Environment in the Central Part of Tyumen

2020 ◽  
pp. 34-42
Author(s):  
Nikolay I. Shchepetkov ◽  
Svetlana B. Kapeleva ◽  
Denis V. Bugaev ◽  
Gregory S. Matovnikov ◽  
Anna S. Kostareva
Keyword(s):  
Urban Environment ◽  
Comprehensive Analysis ◽  
Assessment Criteria ◽  
Field Observations ◽  
General Plan ◽  
Design Solutions ◽  
Methodological Principles ◽  
The City

The article provides a comprehensive analysis of outdoor lighting in the central part of Tyumen (with consideration of conducted field observations) and prospects of its development on the basis of the general plan of illumination of the central part of the city being under design. Main provisions of this general plan as well as methodological principles and assessment criteria of design solutions illustrat-ed by photographs, schemes and visualisations of the illuminated objects are described.

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