Proposal for a soil classification based on parameters alternative or complementary to Vs,30

Luzi, Lucia; Puglia, Rodolfo; Pacor, Francesca; Gallipoli, Maria Rosaria; Bindi, Dino; Mucciarelli, Marco

doi:10.1007/s10518-011-9274-2

Cited by 118 publications

(65 citation statements)

References 24 publications

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“…Gallipoli et al, 2004;Gosar, 2012). Secondly, it can be a complement to the average S-wave velocity in the upper 30 m (V s,30 ) as proposed by Ansal (2004) and Luzi et al (2011). Most of the seismic codes make use of the V s,30 to discriminate soil categories, although some doubts exist about the capability of V s,30 to predict the actual amplification of sediments.…”

Section: Discussionmentioning

confidence: 99%

“…Most of the seismic codes make use of the V s,30 to discriminate soil categories, although some doubts exist about the capability of V s,30 to predict the actual amplification of sediments. Luzi et al (2011) showed that the standard deviation associated with ground motion prediction is significantly reduced when the classification is based on the couple of variables V s,30 -f 0 . Finally, the resonance frequency is useful in calibrating the V s profile, which can be uncertain even when the microtremor array or the MASW measurements are conducted.…”

Section: Discussionmentioning

confidence: 99%

“…This frequency can be used directly to assess the danger of soilstructure resonance or independently, because there is a trend to consider also the resonance frequency or the period of the sedimentary cover in different soil classifications for seismic microzonation (e.g. Ansal, 2004;Luzi et al, 2011). The use of microtremors was later extended to study the dynamic parameters of buildings, for instance to identify their fundamental frequencies Gallipoli et al, 2004;Boutin and Hans, 2008;Gosar et al, 2010).…”

Section: Methodsmentioning

confidence: 99%

“…Another application of the derived isofrequency map is to support soil classification, because recent investigations (Luzi et al, 2011) have shown that the fundamental frequency of sediments can be used with the average S-wave velocity to improve classifications according to different building codes. However, not many examples of such an application of microtremor HVSR results have been published so far.…”

Section: Isofrequency and Hvsr Peak Amplitude Mapsmentioning

confidence: 99%

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Study on the applicability of the microtremor HVSR method to support seismic microzonation in the town of Idrija (W Slovenia)

Gosar

2017

Nat. Hazards Earth Syst. Sci.

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Abstract. The town of Idrija is located in an area with an increased seismic hazard in W Slovenia and is partly built on alluvial sediments or artificial mining and smelting deposits which can amplify seismic ground motion. There is a need to prepare a comprehensive seismic microzonation in the near future to support seismic hazard and risk assessment. To study the applicability of the microtremor horizontal-tovertical spectral ratio (HVSR) method for this purpose, 70 free-field microtremor measurements were performed in a town area of 0.8 km 2 with 50-200 m spacing between the points. The HVSR analysis has shown that it is possible to derive the sediments' resonance frequency at 48 points. With the remaining one third of the measurements, nearly flat HVSR curves were obtained, indicating a small or negligible impedance contrast with the seismological bedrock. The isofrequency (a range of 2.5-19.5 Hz) and the HVSR peak amplitude (a range of 3-6, with a few larger values) maps were prepared using the natural neighbor interpolation algorithm and compared with the geological map and the map of artificial deposits. Surprisingly no clear correlation was found between the distribution of resonance frequencies or peak amplitudes and the known extent of the supposed "soft" sediments or deposits. This can be explained by relatively well-compacted and rather stiff deposits and the complex geometry of sedimentary bodies. However, at several individual locations it was possible to correlate the shape and amplitude of the HVSR curve with the known geological structure and prominent site effects were established in different places. In given conditions (very limited free space and a high level of noise) it would be difficult to perform an active seismic refraction or MASW measurements to investigate the S-wave velocity profiles and the thickness of sediments in detail, which would be representative enough for microzonation purposes. The importance of the microtremor method is therefore even greater, because it enables a direct estimation of the resonance frequency without knowing the internal structure and physical properties of the shallow subsurface. The results of this study can be directly used in analyses of the possible occurrence of soil-structure resonance of individual buildings, including important cultural heritage mining and other structures protected by UNESCO. Another application of the derived free-field isofrequency map is to support soil classification according to the recent trends in building codes and to calibrate V s profiles obtained from the microtremor array or geophysical measurements.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Isofrequency and Hvsr Peak Amplitude Mapsmentioning

confidence: 99%

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Study on the applicability of the microtremor HVSR method to support seismic microzonation in the town of Idrija (W Slovenia)

Gosar

2017

Nat. Hazards Earth Syst. Sci.

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“…For examples, sites are classified into six categories in US [1] mainly from average shear wave velocity Vs30,and are classified into four categories in China from Vs20 and overburden thickness [2]. Site predominate period Tp is suggested to be taken into account in site classification in these years [3], basically from microtremor studies [4], [5]. A way to do this from Vs30is presented in this paper.…”

Section: Introductionmentioning

confidence: 99%

A Way to Take Predominate Period into Account in Site Classification

Li¹,

Tao²,

Zhang³

et al. 2018

dtetr

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In order to take the predominate period Tp into account in site classification，a formula is adopted as the relation between VS20 with Vs30 and Tp. The Tp of 233 sites with data of shear wave velocity profiles from NGA-west2 databank are calculated by two approaches. Site categories of the 233 sites are classified from the formula and their values of VS30 and Tp. The coincidences of the results with the site categories from the profiles directly show that the Tp by Quarter-wavelength Approximation is better than that from Tp' by H/V spectral ratio.

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Characterization of strong‐motion recording sites in the Himalayas and adjoining areas

Gupta

Kumari

2023

Earthquake Engineering and Resilience

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In this paper, an attempt has been made to arrive at sufficiently realistic estimates of the average shear-wave velocity in the top 30 m of the ground (V S30 ) for 200 strong motion recording sites spread over the Himalayas, adjoining Indo-Gangetic plains and northeast Indian regions. This is achieved by extending the application of the horizontal to vertical spectral ratio (HVSR) method for the strong motion recording sites with a limited number of records. The knowledge of surface geology at the recording sites and the V S30 estimates based on the topographic slope method has been utilized as supplementary information to arrive at a good first-order approximation of V S30 for the sites with a single record also. A total of 669 three-component acceleration records have been obtained at the 200 sites considered from 158 different earthquakes in the magnitude range of 2.3-7.9 during 1986-2015. It had not been possible to use this database fruitfully due to lack of the required site characterization. Compared to the costly and time-taking field studies required for the estimation of exact site-specific values, the proposed scheme can be considered to provide a convenient methodology for obtaining sufficiently reliable approximations of V S30 from the recorded strong motion data. The V S30 values obtained in this study are found to be in very good agreement with the site-specific experimental values available for 29 of the sites, establishing the validity of the proposed scheme. An alternative site characterization is also provided in terms of the site soil and the local geological conditions, both defined in terms of three categories specified by indicator variables with values of 0, 1 and 2. Lee and Trifunac have illustrated that this characterization has stronger correlation with the ground motion amplitudes than the V S30 as well as the NEHRP site classes based on broad intervals of V S30 . The site characterization of the 200 strong motion recording sites in the present study will find useful applications in developing region-specific empirical ground motion prediction equations with the site amplification effects modeled realistically and in selecting suitable equations from the published literature using score-based data-driven methods.

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Proposal for a soil classification based on parameters alternative or complementary to Vs,30

Cited by 118 publications

References 24 publications

Study on the applicability of the microtremor HVSR method to support seismic microzonation in the town of Idrija (W Slovenia)

Study on the applicability of the microtremor HVSR method to support seismic microzonation in the town of Idrija (W Slovenia)

A Way to Take Predominate Period into Account in Site Classification

Characterization of strong‐motion recording sites in the Himalayas and adjoining areas

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