Towards a microzonation of the Greater Beirut area: an instrumental approach combining earthquake and ambient vibration recordings

Brax, Marleine; Bard, Pierre‐Yves; Duval, Anne-Marie; Bertrand, Éric; Rahhal, Muhsin-Elie; Jomaa, R.; Cornou, Cécile; Sursock, A.

doi:10.1007/s10518-018-0438-1

Cited by 14 publications

(5 citation statements)

References 55 publications

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“…In order to visualize sparse soil frequencies as continuous fields in the spatial domain (Cadet et al 2011;Brax et al 2018;Pinzón et al 2019;Gallipoli et al 2020), the inverse distance weighting or inverse distance weighted (IDW) method has been applied (Li and Heap 2008). This method allows to estimate the f 0_s and A 0_s values at unsampled points using a linear combination of values at sampled points weighted by an inverse function of the distance from the point of interest to the sampled points.…”

Section: Single-station Seismic Ambient Noise Measurements On Soils A...mentioning

confidence: 99%

Soil-building resonance effect in the urban area of Villa d’Agri (Southern Italy)

Gangone

Gallipoli

Tragni

et al. 2023

Bull Earthquake Eng

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This study aims to evaluate the possible occurrence during seismic shaking of interaction effects between the shallow subsoil and the overlying buildings of the Villa d’Agri town (Southern Italy). From the geological and building heritage points of view, the investigated area represents a typical town along the Apennines chain and therefore the obtained results could be easily exported to similar urban areas. A total of 239 single-station seismic ambient noise measurements were thus performed, 154 on the urban soils and 85 within buildings. Both subsets of measurements were planned to cover the main outcropping lithologies and building typologies. By means of the Horizontal-to-Vertical Noise Spectral Ratio technique, isofrequency and isoamplitude maps have been reconstructed for the whole area. The results evaluated on the 65 tested buildings allowed to infer the empirical relationship between the first vibrational period, T(s), and their height, H(m). Using this relationship and available information on the height of each building, the first vibrational frequency was estimated for 659 buildings belonging to the urban area of Villa d'Agri. Finally, in order to assess the possible occurrence of the double resonance phenomenon, we compared the main frequency of each building with that interpolated for the underlying foundation soil. The results show that the probability of being affected by the double resonance effect is very high only for a couple of buildings, high for about 16% of the buildings, moderate for the 23% and practically null for most buildings (60%).

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Section: Single-station Seismic Ambient Noise Measurements On Soils A...mentioning

confidence: 99%

Soil-building resonance effect in the urban area of Villa d’Agri (Southern Italy)

Gangone

Gallipoli

Tragni

et al. 2023

Bull Earthquake Eng

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“…The application of the ANNs for the estimation of building mean damages requires soil resonance parameters: fsoil and A0HV. Soil investigation campaigns carried out in Beirut and part of it suburbs in the framework of the ANR-LIBRIS project investigated 827 sites using seismic noise recordings (Brax et al, 2018;Salameh et al, 2017;Salloum et al, 2014). The soil fundamental resonance frequency (fsoil) was obtained from these recordings using the HVSR (horizontal to vertical spectral ratio) approach (Nakamura, 1989).…”

Section: Seismic Mean Damage Estimation In Beirutmentioning

confidence: 99%

“…Fig. 16 fsoil and A0HV maps in Beirut derived from the cubic-spline interpolation of the ambient vibration measurements performed in Salloum et al (2014), Salameh et al (2017) andBrax et al (2018) …”

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confidence: 99%

Estimating urban seismic damages and debris from building-level simulations: application to the city of Beirut, Lebanon

Iskandar,

Al Tfaily,

Cornou

et al. 2023

Bull Earthquake Eng

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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“…This step, however, requires defining not only the modulus of the non-linear transfer function, but also its phase. In that aim, we proceed in the same way as proposed in Brax et al, (2018); Sèbe et al, (2018) and Grendas et al, (2022).…”

Section: Figurementioning

confidence: 99%

Empirical approches for non-linear site response: results from the ESG6-blind test.

Régnier

Bard

Cruz

et al. 2023

Preprint

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As a contribution to step 3 of the ESG6 blind prediction exercise, we present an application of two different, purely empirical approaches to estimate the strong ground motion at a soft site ("KUMA") from the observed ground motion at a reference rock site ("SEVO") for the two largest shocks of the Kumamoto 2016 sequence (a foreshock with Mj=6.5, and the mainshock with Mj=7.3). The two methods estimate the non-linear transfer function between a reference rock and a sedimentary site by modifying the linear transfer function derived from weak motion recordings. The modification is based either on a machine learning tool based on a wide collection of Japanese weak and strong motion recordings and the associated site metadata (method M1), or on an estimate of a site-specific parameter related to an average non-linear site response (M2). The acceleration time series are then derived at the sedimentary site of interest using an estimation of the time delay between wave arrivals at the rock and site stations, and a minimum phase assumption for the site transfer function. These predictions were made blindly, but after the ESG6 conference they could be compared both with the actual ground motion recorded at KUMA during the two shocks, and the average and range of all other predictions preformed for this benchmark. The quality of predictions is quantified through various "goodness of fit" (GOF) measures. The agreement may be considered as "excellent" for the foreshock and "good" for the mainshock for usual engineering ground motion parameters (peak values, response spectra, integral parameters), but is very poor in terms of waveform details – as usual for all ground motion predictions even in the linear domain –. The performance of these two purely empirical approaches is at least comparable to those of the numerical simulation methods for the foreshock – if not better -, and slightly worse for the (largest) mainshock. This may come either from an underestimation of non-linear effects, or from the relatively large distance (8 km) between the reference and the target site which limits the reliability of the empirical transfer functions and thus the applicability of the approaches used here for such an instrumental layout. Both of these purely empirical methods provide an honorable prediction of the Fourier spectra and acceleration time histories of the two target events, as the methods required only recordings of weak motions at the target and a referent sites and very simple description of the soil profile. The use of moderate motions to constrain the frequency shift prediction for the second method and the consideration of an alternative phase modification are possible ways to improvement.

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Towards a microzonation of the Greater Beirut area: an instrumental approach combining earthquake and ambient vibration recordings

Cited by 14 publications

References 55 publications

Soil-building resonance effect in the urban area of Villa d’Agri (Southern Italy)

Soil-building resonance effect in the urban area of Villa d’Agri (Southern Italy)

Estimating urban seismic damages and debris from building-level simulations: application to the city of Beirut, Lebanon

Empirical approches for non-linear site response: results from the ESG6-blind test.

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