Constraints for the Vs profiles from engineering-geological qualitative characterization of shallow subsoil in seismic microzonation studies

Romagnoli, Gino; Tarquini, Emanuele; Porchia, Attilio; Catalano, Stefano; Albarello, Dario; Moscatelli, Massimiliano

doi:10.1016/j.soildyn.2022.107347

Cited by 10 publications

(2 citation statements)

References 32 publications

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“…Results may be used in the future for comparison with other Italian estimates (Romagnoli et al, 2022) or combined with ambient vibration measurements to define the thickness of the resonant sedimentary layers (D'Amico et al, 2008;Giannini et al, 2021).…”

Section: Statistical Analysis Of Shear Waves Variability With Depthmentioning

confidence: 99%

PERL: a dataset of geotechnical, geophysical, and hydrogeological parameters for earthquake-induced hazards assessment in Terre del Reno (Emilia-Romagna, Italy)

Varone¹,

Carbone²,

Baris³

et al. 2023

Nat. Hazards Earth Syst. Sci.

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Abstract. In 2012, the Emilia-Romagna region (Italy) was struck by a seismic crisis characterized by two main shocks (ML 5.9 and 5.8) which triggered relevant liquefaction events. Terre del Reno is one of the municipalities that experienced the most extensive liquefaction effects due to its complex geostratigraphic and geomorphological setting. This area is indeed located in a floodplain characterized by lenticular fluvial channel bodies associated with crevasse and levee clay–sand alternations, related to the paleo-Reno River. Therefore, it was chosen as a case study for the PERL project, which aims to define a new integrated methodology to assess the liquefaction susceptibility in complex stratigraphic conditions through a multi-level approach. To this aim, about 1800 geotechnical, geophysical, and hydrogeological investigations from previous studies and new realization surveys were collected and stored in the PERL dataset. This dataset is here publicly disclosed, and some possible applications are reported to highlight its potential.

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Section: Statistical Analysis Of Shear Waves Variability With Depthmentioning

confidence: 99%

PERL: a dataset of geotechnical, geophysical, and hydrogeological parameters for earthquake-induced hazards assessment in Terre del Reno (Emilia-Romagna, Italy)

Varone¹,

Carbone²,

Baris³

et al. 2023

Nat. Hazards Earth Syst. Sci.

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“…The mechanical properties of the considered materials are reported in Table 1. In particular, the shear wave velocity value, V S , adopted for the soft soils is representative of the cover materials typically emerging on the Italian territory [74][75][76], while the V S value of the shear band has been reduced to account for the stiffness degradation due to shear strain localisation. A typical value of 800 m/s was assigned to the seismic bedrock.…”

Section: Constitutive Assumptionsmentioning

confidence: 99%

Investigating the Influence of a Pre-Existing Shear Band on the Seismic Response of Ideal Step-like Slopes Subjected to Weak Motions: Preliminary Results

2023

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The assessment of slope susceptibility to seismically-induced displacements receives wide attention in the geotechnical earthquake engineering field, but the alteration of the seismic wave inside the slope and at the ground surface due to the presence of a shear band confining a quiescent landslide body is rarely investigated. This paper describes the preliminary results of the numerical analysis of two step-like FE models, reproducing a gentle slope and steep cutting subjected to weak earthquakes, thus focusing on seismic wave amplification processes only. The results show that the higher the thickness of the weakened zone, the higher the maximum value of the amplification factors predicted at the ground surface. For gentle slopes affected by a landslide body confined by a thick shear band, the highest amplification factors are expected in the longer period range of 0.7–1.1 s, while the highest level of amplification is achieved in the intermediate period interval of 0.4–0.8 s in the case of steep slopes. In addition, the parasitic vertical component of acceleration can be considerably amplified beyond the crest and at the toe of the slope for increasing band thickness, especially in the case of steep topography, for which the effects of the shear band morphology enhance those related to the topographic profile. Finally, the fundamental frequency of the sloping deposit is not particularly affected by the presence of the shear band, while the amplitude of the amplification function at the fundamental frequency is clearly related to its thickness.

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Influence of local site effects on seismic risk maps and ranking of Italian municipalities

Sabetta

Fiorentino

Bocchi³

et al. 2023

Bull Earthquake Eng

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The latest studies concerning seismic risk assessment in Italy were developed without considering the site geo-lithological effects, thus limiting the assessment to rock soil type. In this study, for the evaluation of site amplification effects, we used the results of recent works based on the Italian seismic microzonation data. As this first study is performed for the entire Italian territory at the municipality scale, the site amplification factors (AFs) have been assigned to the chief town of each of the 7715 Italian municipalities, assuming that the building stock is concentrated in that small area. The AFs have been compared with those foreseen by the Italian building code (NTC2018). The PGA amplification with the new AFs ranges from 1 to 2.2 bringing to an average increase of 75% in the hazard, compared to 27% if using the NTC2018 amplification. The seismic risk has been evaluated using the probabilistic hazard assessment adopted in the NTC2018 and recent vulnerability/exposure models developed for Italy. The residential building stock was subdivided into 5 vulnerability classes (3 for masonry and 2 for concrete) derived from the national census data and further refined using the construction age and building height. The results show that, for a rock site condition, the loss estimates are comparable with those of previous works in terms of casualties, homeless, and economic damage. The introduction of the site effects brings to a significant increase in the expected losses resulting higher than the historical data retrieved from a careful analysis of the major Italian earthquakes. This suggests the importance of developing new fragility curves based on updated AFs. To support the implementation of risk reduction programs, a seismic risk index is introduced, allowing a municipality ranking by risk, a cost estimation of the seismic retrofitting in the highest risk municipalities, and an assessment of the consequent risk reduction.

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Constraints for the Vs profiles from engineering-geological qualitative characterization of shallow subsoil in seismic microzonation studies

Cited by 10 publications

References 32 publications

PERL: a dataset of geotechnical, geophysical, and hydrogeological parameters for earthquake-induced hazards assessment in Terre del Reno (Emilia-Romagna, Italy)

PERL: a dataset of geotechnical, geophysical, and hydrogeological parameters for earthquake-induced hazards assessment in Terre del Reno (Emilia-Romagna, Italy)

Investigating the Influence of a Pre-Existing Shear Band on the Seismic Response of Ideal Step-like Slopes Subjected to Weak Motions: Preliminary Results

Influence of local site effects on seismic risk maps and ranking of Italian municipalities

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