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The seismic effects of complex, deep, and inhomogeneous sites constitute a significant research topic. Utilizing geological borehole data from the Suzhou urban area, a refined 2D finite element model with nonuniform meshes of a stratigraphic section crossing the Suzhou region was established. Within the ABAQUS/explicit framework, the spatial inhomogeneity of soils, including the spatial variation of S-wave velocity structures, was considered in detail. The nonlinear and hysteretic stress–strain relationship of soil was characterized using a non-Masing constitutive model. Ricker wavelets with varying peak times, peak frequencies ( f p ), and amplitudes were selected as input bedrock motions. The analysis revealed the spatial distribution characteristics of 2D nonlinear seismic effects on the surface of deep and complex sedimentary layers. The surface peak ground acceleration (PGA) amplification coefficients initially increased and then decreased as f p increases. The surface PGA amplification was most pronounced when the f p is close to the site fundamental frequency. Additionally, when f p  = 0.1 Hz, the surface PGA amplification was found to depend solely on the level of bedrock seismic shaking, with amplification factors ranging from 1.20 to 1.40. Furthermore, the ensemble empirical mode decomposition components of seismic site responses can intuitively reveal the variations in time–frequency and time–energy characteristics of Ricker wavelets as they propagate upward from bedrock to surface.

The strong ground motion effect is amplified or de-amplified due to the change in subsoil condition. Local soil properties prediction is critical for earthquake-safe areas and the earthquake hazard assessment of existing structures. This study was carried out with time-domain 1D Nonlinear analysis to understand the soil response characteristics of the Arifiye district. In this sense, geotechnical drilling at 47 points and surface wave analysis at 44 points were performed. Site response profiles in the study area were analyzed with the DeepSoil program for Mw:7.0 1967 Mudurnu and Mw:7.4 1999 Kocaeli earthquake scenarios. Peak spectral acceleration (Pga) and spectral acceleration (Sa) values were determined in the analysis of the Mudunu scenario as 0.11–0.24 g and 0.44–1 g, respectively. The Kocaeli scenario’s Pga and Sa distribution were obtained in a wide range of 0.2–0.56 g and 0.47–2.3 g, respectively, compared to the Mudurnu scenario. Especially in the Mw:7.4 model, high Pga (> 0.3 g) and Sa (> 1 g) values were obtained in the uncemented units located north of the study area. Kocaeli scenario results showed that the spectral accelerations at the surface in soil groups D and E were higher than the Turkish Building Earthquake Code building requirements. It is necessary to update the earthquake design spectra site-specific. The results clearly showed the effect of ground conditions and strong ground motion selection on earthquake-resistant building design.

Based on criticisms raised in the past by researchers about the effectiveness of the design rules reported in the European seismic code for the design of concentrically braced frames, a new design procedure has been proposed and included in the upcoming version of Eurocode 8. The upcoming version of Eurocode 8 is in the enquiry stage. Hence, it is important to evaluate the effectiveness of the design procedure reported in the code using accurate numerical models and seismic inputs. In the present paper, a four-story building with concentrically braced frames in the chevron configuration is designed according to the upcoming version of Eurocode 8. A seismic performance assessment is carried out by the means of multiple-stripe analyses performed on refined numerical models. The seismic input is defined based on one-dimensional local site response analyses. The numerical analyses prove that the use of local site response analysis to properly account for the soil-filtering effects is of paramount importance, and that the design procedure reported in the upcoming version of Eurocode 8 for chevron concentrically braced frames leads to reasonably low probabilities of exceeding the considered limit states.

The choice of stiffness profile can be crucial in a site response analysis. This research aims to study site response predictions at the large-scale seismic test site in Lotung, Taiwan, employing three different approaches to choosing the stiffness profile in nonlinear and equivalent linear analyses. These approaches consider point average, layer average, and deposit average stiffness profiles. One strong and one weak earthquake event recorded at the site are simulated with these three stiffness profile approaches. Moreover, the stiffness profiles are tested under sets of seven modified real input motions (selected from the European Strong-Motion Database) at various seismic intensity levels. The results indicate that the different stiffness profiles have a minimal effect on the nonlinear site response predictions, in particular for input motions having a PGA greater than or equal to 0.05 g. The spectral acceleration values and PGA and shear strain profiles from nonlinear site response analyses change negligibly when using different approaches to derive the stiffness profile. In the equivalent linear site response analysis, the spectral acceleration predictions are strongly influenced by the stiffness profile approach, regardless of the PGA level of the input motions. The stiffness profile has a more significant role in equivalent linear site response analysis than in nonlinear site response analysis. Therefore, the point average stiffness profile should be used in equivalent linear site response analysis.

Liquefaction can significantly alter the ground response. However, no existing design spectrum accounts for the severity of soil liquefaction. This work aims to develop correction factors that can be used to adjust code-based design spectra to reflect the specific liquefaction susceptibility of a site. The correction factor is derived as the ratio of response spectra calculated by two types of 1D nonlinear site response analyses: effective stress analysis, which can model porewater pressure (PWP) generation, and total stress analysis. We considered seven real profiles and 200 motions in our analysis. Four combinations of soil nonlinear models and PWP generation models are also utilized to account for epistemic uncertainties. Results show that the response spectral ratio for liquefied sites typically falls below one for periods less than 1–2 s and rises above one for longer periods. Meanwhile, the response spectral ratio reflects the overall liquefaction susceptibility influenced by PWP, factor of safety, and liquefiable layer depth, while the liquefaction potential index (LPI) captures their complex interplay. Accordingly, we propose four LPI-dependent factors: three correction factors for peak ground acceleration, 0.2 s spectral acceleration (Sa), and 1.0 s Sa, and a long-period adjustment factor applicable for periods exceeding 1 s. The correction factors linearly decrease with increasing LPI, while the adjustment factor exhibits the opposite trend. A design spectrum for a liquefiable site can be readily constructed by adjusting the code-based design spectrum using the proposed correction factor, as illustrated in the example. This approach is applicable as long as LPI is available from a simplified liquefaction analysis or a liquefaction hazard map.

In civil engineering, one of the main problems is the stability of structures. Blast vibrations can be one of several elements influencing the stability of these structures. In order to prevent any effects on the structures, the maximum suggested values of the peak particle velocity and frequency from the blast are generally determined using the existing appropriate government rules and industry standards as reference. In this paper, the effect of these vibration on the site response has been investigated. Parameters such as peak ground acceleration, Pseudo spectral acceleration and maximum stress and strain has been compared for two different soil models. The results indicate that the soft soil has a significant impact and amplifies the input parameters considerably.

Seismic microzonation is performed to assess the seismic risk in an area. In this paper, seismic microzonation for Lahore, Pakistan has been carried out. Firstly, the Geotechnical and geological properties of soils in the region were classified based on 119 boreholes. Two downhole tests were performed to measure the dynamic in-situ properties of soil. The design spectra for Lahore city from BCP 2007 and 2021 were used as target spectra to develop two synthetic acceleration time histories respectively. Afterward, one-dimensional non-linear site response analysis was performed at 33 sites having depth of 30 m for evaluation of parameters such as peak ground acceleration and spectral acceleration at the ground surface. Major seismic hazards considered for the seismic risk assessment are (1) peak ground acceleration at the ground surface, (2) surface spectral acceleration and (3) spectral amplification in the top 30 m of soil. All the major hazards estimated above were also used to prepare a seismic risk map of Lahore. Additionally, two site-specific design spectra were proposed in accordance with the soil classes D and E. The results of this study demonstrate the importance of micro-scale seismic studies to quantify the seismic risks associated with earthquakes.

The Arctic seas are now of particular interest due to their prospects in terms of hydrocarbon extraction, development of marine transport routes, etc. Thus, various geohazards, including those related to seismicity, require detailed studies, especially by instrumental methods. This paper is devoted to the ocean-bottom seismographs (OBS) based on broadband molecular–electronic transfer (MET) sensors and a deployment case study in the Laptev Sea. The purpose of the study is to introduce the architecture of several modifications of OBS and to demonstrate their applicability in solving different tasks in the framework of seismic hazard assessment for the Arctic seas. To do this, we used the first results of several pilot deployments of the OBS developed by Shirshov Institute of Oceanology of the Russian Academy of Sciences (IO RAS) and IP Ilyinskiy A.D. in the Laptev Sea that took place in 2018–2020. We highlighted various seismological applications of OBS based on broadband MET sensors CME-4311 (60 s) and CME-4111 (120 s), including the analysis of ambient seismic noise, registering the signals of large remote earthquakes and weak local microearthquakes, and the instrumental approach of the site response assessment. The main characteristics of the broadband MET sensors and OBS architectures turned out to be suitable for obtaining high-quality OBS records under the Arctic conditions to solve seismological problems. In addition, the obtained case study results showed the prospects in a broader context, such as the possible influence of the seismotectonic factor on the bottom-up thawing of subsea permafrost and massive methane release, probably from decaying hydrates and deep geological sources. The described OBS will be actively used in further Arctic expeditions.

The local site conditions have great impact on the characteristics of input motions propagating along the soil deposits. This eventually contributes to the damages of earthquake events to urban areas. This study reports the local site effect during the 08.11.2021 earthquake event occurred near the Konya city. For this, five input ground motions of the earthquake event recorded at five different stations are investigated. The stations are positioned at varied soil classes of A, B and C, and no recording is available on the class D site. In addition, site response analyses are conducted using five soil profiles from the site of Konya city. The soil profiles are simulated in the Deepsoil programme adapting equivalent linear approach in frequency domain. The spectral accelerations of the recorded input ground motions reflect obviously the influence of the local site conditions. When the soil site (where the earthquake is recorded) gets softer, the spectral peaks appear to shift to the longer periods. The site response analyses at the sites in the Konya city also imply such effect. The analysis of the soft soil deposit with the Vs of 175 m/s expresses de-amplification of the spectral accelerations at the shorter periods and amplifications at the longer periods. Moreover, the site response analyses tend to express good indication of the spectral amplification factors for different soil classes. These suggest that the local site conditions in the studied area, in addition to the peak ground acceleration level of the earthquake event, can increase the level of building damages. Overall, the study highlights the impact of local site conditions on the spectral accelerations of input motions and potential of site response analysis to speculate that effect.

For the earthquake design of underground and basement structures, soil displacement needs to be predicted. In the present study, simplified methods for the prediction of soil period, damping ratio, and soil displacement profile were studied. First, existing methods for the estimation of site periods (in the elastic range) were applied to 440 actual soil profiles, and accuracy was evaluated by comparing the predictions with the site periods calculated by the wave propagation theory. The result showed that the simplified Rayleigh method and eigenvalue analysis showed better predictions. Then, modification coefficients for the inelastic site period and equivalent damping ratio (i.e., the effect of inelastic soil properties) were proposed based on the results of an equivalent linear site response analysis (SRA). Finally, a simplified method for the prediction of soil displacement profile was proposed. The proposed method was applied to 440 soil profiles, and the predicted soil displacement profiles agreed with the SRA results.