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The seismic response characteristics of the Yellow River terrace are crucial, as it is one of the key human activity areas. Seismic response characteristics of Yellow River terrace stations in Ningxia were analyzed using strong-motion earthquake records from seismic observations in the Loess Plateau and corresponding station data, employing the Horizontal-to-Vertical Velocity Response Spectrum Ratio method. The seismic vulnerability coefficient (Kg) was computed, and the bedrock depth was estimated. The results indicate that the spectral ratio curves of the Yellow River terrace can be classified into three types: single-peak, multi-peak, and ambiguous-peak types. The predominant period of the terraces ranges from 0.12 to 1.22 s, and the amplification factor ranges from 2.87 to 10.29. The calculated Kg values range from 2.09 to 63.24, and the bedrock depth ranges from 10.68 to 168.11 m. The site's predominant period, amplification factor, high Kg values, and deep bedrock depths can significantly impact seismic design, potentially leading to greater damage during earthquakes. Based on the predominant period, Kg values, and bedrock depth, the seismic vulnerability of Yinchuan is assessed to be high. [ABSTRACT FROM AUTHOR]

Seismic response analysis is a key aspect in earthquake geotechnical engineering, as it provides important insights into the behavior of soils when exposed to seismic forces. This research compares equivalent linear and non-linear models in the central coastal region of Bengkulu, which is known for its complex geology and high seismicity. By evaluating the accuracy and reliability of each model in predicting ground motion amplification, this research aims to provide useful recommendations for seismic design. The research method uses one-dimensional equivalent linear and nonlinear propagation modeling, namely Pressure Dependent Hyperbolic (PDH). The analysis resulted in the parameters of Peak Ground Acceleration (PGA), time history acceleration, spectral response acceleration, and amplification factor. The equivalent linear method consistently produced higher values for peak ground acceleration (PGA), spectral response acceleration, time history acceleration, and amplification factor compared to the nonlinear method. The analysis results show that the equivalent linear PGA values are in the range of 0.32g to 0.63g, while the nonlinear values range from 0.20g to 0.52g. The resulting spectral responses are averaged over the design spectrum within 0.2s to 0.9s, which can affect low-to high-ceilinged buildings. The equivalent linear amplification factor has a range of 1.59 to 1.91, while the nonlinear has a range of 0.80 to 1.59. Both methods have their advantages, with the nonlinear approach offering greater accuracy for large seismic events, while the equivalent linear model remains useful for preliminary analysis. Hopefully, these findings will improve the understanding of ground response in coastal areas and provide valuable data for improving infrastructure resilience in earthquake-prone areas around the world. [ABSTRACT FROM AUTHOR]

In recent decades, China has collected extensive strong-motion data from the Loess Plateau, which is valuable for understanding the dynamic characteristics of loess sites and the effects of site conditions on seismic motions. The horizontal-to-vertical Fourier spectrum ratio (HVSR) and the horizontal-to-vertical velocity response spectrum ratio (VRSR) are widely used to study site dynamics. This study analyzes strong-motion data from the Loess Plateau to identify key features of the HVSR and VRSR curves. The results show that these spectral ratio curves effectively capture the dynamic behaviors of loess sites, minimizing the influences of earthquake magnitude and propagation path. While the spectral ratio peaks are less affected by magnitude, epicentral distance, and focal depth, they are significantly influenced by site conditions. Conversely, the dominant periods estimated from these curves are strongly influenced by magnitude, epicentral distance, and focal depth. For sites located on the Loess Plateau, the average amplification factor is approximately 3, with a mean predominant period of 0.4 s. These results provide valuable insights into the dynamic characteristics of loess sites and have practical implications for seismic design in the region. [ABSTRACT FROM AUTHOR]

Abstract Civil structures are prone to dynamic loadings such as strong winds or ground excitations where torsion becomes an ongoing issue. This arises from a lack of coincidence of the center of mass (CM) and rigidity (CR), known as eccentricity. Seismic design codes often introduce two types of eccentricity: inherent (geometric) and accidental. To account for structural or ground motion uncertainties, an assumption-based solution is provided by many code provisions, which considers the accidental eccentricity as a percentage (5% or 10%) of the building length perpendicular to the direction of exposed ground motion. In this study, as an alternative way to the code design parameters, a new design eccentricity formula that considers the frequency ratio (torsional frequency/translation frequency) and an effective radius of gyration to account for torsional irregularity is considered. For the extended validation of the proposed method, eighteen model buildings with six different floor plans were chosen, representing low, medium-height, and high-rise buildings. Each floor plan had model buildings with three, seven, and twelve stories. The buildings were subjected to selected bidirectional earthquake ground motions and had time history analyses performed. The results of the proposed method were compared to code provision methods, obtained using equivalent lateral force procedures, and also to those obtained utilizing the time history analysis results. It was shown that the proposed method was more effective in estimating the impact of torsional eccentricity and provided a better understanding of its impact on structural dynamic characteristics.

Topographic influences of the ground motions in 3D geological configurations have been addressed using Spectral Element Method as implemented in SPECFEM3D code developed to simulate seismic wave propagation. Hexahedral mesh model was constructed to which the 1987 Jinka earthquake source characteristics were applied. The simulation results have shown that topography has significant effects on ground motion and changes PGA values by ± 55% compared to the flat topography. PGA amplification variation between valley and hill/ridge top is observed to be in the order of 1.6. The study indicates that there is PGA amplification on top of hills and de-amplifications occur at the base. Valleys and flat areas generally show low and negative amplification factors. It is observed that topographic features play significant roles in concentrating or diffusing seismic energy. This was confirmed by observing the behaviour of PGA values along selected profiles and by comparing PGA maps with and without topography. The study shows that topography has serious consequences and must be taken into account to minimise damage to infrastructures and safeguard human lives and suggests the importance of incorporating the effects of topographic features in any seismic hazard analysis schemes in densely populated mountainous regions.

Civil structures are prone to dynamic loadings such as strong winds or ground excitations where torsion becomes an ongoing issue. This arises from a lack of coincidence of the center of mass (CM) and rigidity (CR), known as eccentricity. Seismic design codes often introduce two types of eccentricity: inherent (geometric) and accidental. To account for structural or ground motion uncertainties, an assumption-based solution is provided by many code provisions, which considers the accidental eccentricity as a percentage (5% or 10%) of the building length perpendicular to the direction of exposed ground motion. In this study, as an alternative way to the code design parameters, a new design eccentricity formula that considers the frequency ratio (torsional frequency/translation frequency) and an effective radius of gyration to account for torsional irregularity is considered. For the extended validation of the proposed method, eighteen model buildings with six different floor plans were chosen, representing low, medium-height, and high-rise buildings. Each floor plan had model buildings with three, seven, and twelve stories. The buildings were subjected to selected bidirectional earthquake ground motions and had time history analyses performed. The results of the proposed method were compared to code provision methods, obtained using equivalent lateral force procedures, and also to those obtained utilizing the time history analysis results. It was shown that the proposed method was more effective in estimating the impact of torsional eccentricity and provided a better understanding of its impact on structural dynamic characteristics. [ABSTRACT FROM AUTHOR]

Topographic influences of the ground motions in 3D geological configurations have been addressed using Spectral Element Method as implemented in SPECFEM3D code developed to simulate seismic wave propagation. Hexahedral mesh model was constructed to which the 1987 Jinka earthquake source characteristics were applied. The simulation results have shown that topography has significant effects on ground motion and changes PGA values by ± 55% compared to the flat topography. PGA amplification variation between valley and hill/ridge top is observed to be in the order of 1.6. The study indicates that there is PGA amplification on top of hills and de-amplifications occur at the base. Valleys and flat areas generally show low and negative amplification factors. It is observed that topographic features play significant roles in concentrating or diffusing seismic energy. This was confirmed by observing the behaviour of PGA values along selected profiles and by comparing PGA maps with and without topography. The study shows that topography has serious consequences and must be taken into account to minimise damage to infrastructures and safeguard human lives and suggests the importance of incorporating the effects of topographic features in any seismic hazard analysis schemes in densely populated mountainous regions. [ABSTRACT FROM AUTHOR]

Wilayah Kemiling yang terletak di Kota Bandar Lampung sering kali mengalami gempa lokal dengan magnitudo kecil. Gempa ini terjadi secara berulang dan dirasakan di daerah Kemiling dan sekitarnya. Hal tersebut dapat menimbulkan kekhawatiran bagi warga dan dapat merusak bangunan. Fokus utama pada studi ini adalah untuk memahami bagaimana karakteristik tanah dan indeks kerentanan seismik di daerah tersebut. Untuk meminimalisir dampak kerusakan akibat gempa, perlu dilakukan mikrozonasi pada wilayah rawan gempa. Parameter mikrozonasi yang digunakan untuk mengetahui karakteristik tanah antara lain amplifikasi (A0), frekuensi natural (f0), indeks kerentanan seismik (Kg), periode dominan (T0), dan kecepatan gelombang geser hingga kedalaman 30 meter (VS30). Sebanyak 65 titik pengukuran mikrotremor telah diukur di Kecamatan Kemiling dan sekitarnya meliputi kota Bandar Lampung, Kecamatan Gedong Tataan, dan Kecamatan Natar. Pada penelitian ini digunakan analisis metode Horizontal to Vertical Spectral Ratio (HVSR) dan didapatkan bahwa frekuensi natural berkisar antara 0,5-31,47 Hz, periode dominan 0,03-2,0 sekon, amplifikasi 0,76-7,67 kali penguatan, indeks kerentanan seismik 0,05-76,31, dan VS30 49,61-777,80 m/s. Hasil penelitian menunjukkan bahwa wilayah barat daya hingga utara Kemiling memiliki risiko kerentanan yang lebih tinggi dibandingkan wilayah lainnya dengan tipe tanah berupa tanah lunak. Oleh karena itu, diperlukan tindakan mitigasi yang tepat, termasuk pengembangan rencana mitigasi risiko, pemantauan lanjutan, dan keterlibatan aktif masyarakat dalam perencanaan darurat.

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Seismic response analysis is a key aspect in earthquake geotechnical engineering, as it provides important insights into the behavior of soils when exposedtoseismic forces. This research compares equivalent linear and non-linear models in the central coastal region of Bengkulu, which is known for its complex geology and high seismicity. By evaluating the accuracy and reliability of each model in predicting ground motion amplification, this research aims to provide useful recommendations for seismic design. The research method uses one-dimensional equivalent linear and nonlinear propagation modeling, namely Pressure Dependent Hyperbolic (PDH). The analysis resulted in the parameters of Peak Ground Acceleration (PGA), time history acceleration, spectral response acceleration, and amplification factor. The equivalent linear method consistently produced higher values for peak ground acceleration (PGA), spectral response acceleration, time history acceleration, and amplification factor compared to the nonlinear method. The analysis results show that the equivalent linear PGA values are in the range of 0.32g to 0.63g, while the nonlinear values range from 0.20g to 0.52g. The resulting spectral responses are averaged over the design spectrum within 0.2 s to 0.9 s, which can affect low- to high-ceilinged buildings. The equivalent linear amplification factor has a range of 1.59 to 1.91, while the nonlinear has a range of 0.80 to 1.59. Both methods have their advantages, with the nonlinear approach offering greater accuracy for large seismic events, while the equivalent linear model remains useful for preliminary analysis. Hopefully, these findings will improve the understanding of ground response in coastal areas and provide valuable data for improving infrastructure resilience in earthquake-prone areas around the world.

This study, conducted in the Banarli district of Tekirdag Province, Turkey, focuses on soil reaction analysis and liquefaction potential in an area where a landfill and an associated power plant are planned. The research was examined with a one-dimensional ground response analysis to understand seismic behaviour, revealing the varied responses of soil categories to seismic waves. Soft soil layers were found to lengthen the dominant period of oscillation rather than significantly enhancing peak acceleration during seismic events. Earthquake records specific to the region were crucial for accurate assessments. The study comprehensively assessed liquefaction potential using various estimation methods, including the probability of liquefaction (PL), liquefaction potential index (LPI), and liquefaction risk index (IR). Moreover, this study examined liquefaction potential based on Standard Penetration Test (SPT) results, identifying susceptibility in the clayey sand layer at a depth of 3 to 12 meters. Recommendations for soil improvement measures are made to mitigate the risk. This research highlights the need for “customized seismic protocols” and emphasizes the importance of “site-specific assessments” in construction projects. By addressing susceptibility to liquefaction and proposing targeted ground improvement strategies, we contribute to safer and more resilient infrastructure development.

Local soil conditions play a significant role in the intensity variations of seismic waves during earthquakes. These variations can be either amplified or de-amplified depending on the specific soil conditions. This study aimed to assess the impact of different soil profiles on seismic site responses. The study considered four types of site profiles: sand (Sa), clay (Cl), sand overlying clay (SaCl), and clay overlying sand (ClSa) profiles. To simulate the ground motion, we selected seven sets of strong earthquake records from the European Strong-Motion Database. These records were selected according to Eurocode-8 with a peak ground acceleration (PGA) of 0.24 g, site class A using REXEL computer program. The records were then applied to the bedrock at a depth of 30 meters. Subsequently, a series of 1-D equivalent linear (EQL) response analyses were performed using the STRATA. Amplification factors (AFs) and surface acceleration time histories provided quantitative evaluations for our analysis results. The results demonstrated that site profiles with clay overlying bedrock (SaCl and Cl profiles) exhibited higher seismic amplification and peak ground acceleration in comparison to site profiles with sand overlying bedrock (Sa and ClSa profiles). The maximum median AF is calculated from the SaCl site profile, while the minimum median AF was calculated from the ClSa profile. The relative difference between the maximum and the minimum median AFs was about 33.7%. Based on these results, we can conclude that soft local soils have a pronounced effect on the amplification of seismic waves compared to stiff local soils. [ABSTRACT FROM AUTHOR]

The position of Bengkulu Province, which is flanked by the subduction zone between the Euro-Asian and Indian-Australian plates to the west, and the Sumatra Fault zone to the east, makes Bengkulu City one of the areas prone to earthquake disasters. Muara Bangkahulu District is one of the sub-districts in Bengkulu City. Muara Bangkahulu sub-district is an area that functions as a government centre, trade and service centre, and one of the education centres in Bengkulu City. This study aims to determine the ground response in the Muara Bangkahulu sub-district area during an earthquake. The wave propagation method used in this study is a one-dimensional equivalent of linear and nonlinear modelling that propagates earthquake waves from bedrock to surface. The results of this study are Peak Ground Acceleration (PGA), amplification factor, earthquake acceleration time history, and acceleration spectra response. The results of this analysis will be compared between equivalent linear and nonlinear values. The results of this study can also help us realise and further consider the value of seismic design in the Muara Bangkahulu sub-district area, mainly if a stronger earthquake occurs in the future.

The Integrated Laboratory Building of Political and Social Science Faculty, located in a seismic-prone area, has been the subject of a comprehensive study of its performance using seismic response analysis. This research has yielded significant findings, gathering crucial secondary data, such as soil layers, bedrock depth, building structure, and earthquake wave information. The seismic response analysis, conducted by referencing the synthetic earthquake wave from the Bengkulu–Mentawai earthquake in 2007, with a magnitude of Mw 8.6, has provided a comprehensive overview of the earthquake waves at the foundation soil layers. The data, analysed using the finite element method to understand the structural response, revealed that the Peak Ground Acceleration (PGA) and amplification factor at the surface soil layer are 0.220g and 1.429, respectively. The most critical PGA and amplification factors at the foundation soil layer are 0.147g and 0.955. Structural analysis has revealed internal forces and beam elements experiencing over-strength, necessitating retrofitting the affected structural elements to reduce the impact. One practical and highly effective method of retrofitting involves increasing the beam dimensions by 53.12%. With retrofitting, the impact of structural deformation can be minimised, enhancing the building’s resilience in case of an earthquake of equal or greater magnitude. These findings underscore the importance of our research and highlight the significant role of engineers, architects, and researchers in ensuring the safety and longevity of structures in seismic-prone areas.

In recent decades, China has collected extensive strong-motion data from the Loess Plateau, which is valuable for understanding the dynamic characteristics of loess sites and the effects of site conditions on seismic motions. The horizontal-to-vertical Fourier spectrum ratio (HVSR) and the horizontal-to-vertical velocity response spectrum ratio (VRSR) are widely used to study site dynamics. This study analyzes strong-motion data from the Loess Plateau to identify key features of the HVSR and VRSR curves. The results show that these spectral ratio curves effectively capture the dynamic behaviors of loess sites, minimizing the influences of earthquake magnitude and propagation path. While the spectral ratio peaks are less affected by magnitude, epicentral distance, and focal depth, they are significantly influenced by site conditions. Conversely, the dominant periods estimated from these curves are strongly influenced by magnitude, epicentral distance, and focal depth. For sites located on the Loess Plateau, the average amplification factor is approximately 3, with a mean predominant period of 0.4 s. These results provide valuable insights into the dynamic characteristics of loess sites and have practical implications for seismic design in the region.

Penelitian respons dinamik dan indeks kerentanan seismik sangat penting untuk memperkirakan dampak kerentanan lapisan permukaan dan kerusakan bangunan ketika terjadi gempa bumi. Penelitian ini bertujuan untuk mengidentifikasi respons dinamik Kecamatan Nambo, Kota Kendari serta menentukan area-area dengan perlapisan tanah yang sangat rentan. Data mikrotremor diolah menggunakan Geopsy 2.0.5 untuk memperoleh kurva HVSR (Horizontal to Vertical Spectral Ratio) serta parameter respons dinamik tanah berupa frekuensi dominan dan faktor amplifikasinya yang digunakan untuk menghitung indeks kerentanan seismik. Nilai frekuensi dominan Kecamatan Nambo berkisar antara 0,7 Hz- 3,63 Hz yang termasuk dalam kategori tanah Tipe II dan III. Area dengan frekuensi rendah menunjukkan penebalan lapisan alluvial yang merupakan produk sedimentasi permukaan. Interpolasi nilai indeks kerentanan seismik (kg) menunjukkan area Kecamatan Nambo yang memiliki kerentanan tinggi meliputi Kelurahan Pentoahan dan Nambo.

Premixed hydrogen-air laminar flames with equivalence ratios ranging from 0.32 to 2.68 adopt different shapes during propagation in a gap (from 1. 5 mm to 4. 2 mm) between two plates. Thermodiffusive and Darrieus–Landau instabilities are visible for lean mixture while Darrieus–Landau is visible at higher equivalent ratio. Using for the first time simultaneous schlieren visualisation in this configuration, we were able to make two important observations: (i) either symmetric or asymmetric shapes are observed and quantified within the gap as a function of equivalence ratio and gap thickness; (ii) 3D flame surface for unstable laminar flame was estimated. These results validate (or invalidate) the quasi-2D assumptions made in Hele-Shaw cells. Linear stability analysis allowed us to find an a priori criteria differentiating symmetric and asymmetric cases. Finally, curvature effect on flame speed enhancement relative to surface amplification is estimated for unstable hydrogen-air laminar flames. This experimental 3D amplification factor provides means to take into account instabilities effect on large scale turbulent models. • The first quantification of the asymmetry factor in Hele-Shaw cells is presented. • Asymmetric cases may occur when the channel gap exceeds the cut-off wavelength. • The curvature between the plates results in an increase of the 2D flame surface by 25%–50% • For the first time, we have estimated the 3D wrinkling factor for unstable flames. • Amplification factor measurements show values greater than one for lean H2 mixture. [ABSTRACT FROM AUTHOR]

A computational methodology is presented for calculating the spatial evolution of Tollmien–Schlichting (T–S) waves and their amplitude growth-rate factor in substantially nonparallel compressible flows, based on a global stability analysis of stationary solutions of the full Navier–Stokes (N–S) equations. Three stages of this methodology (obtaining a stationary solution, as well as carrying out a global stability analysis and its postprocessing) are described, and the results are presented of its validation based on the comparison of the results of calculating the characteristics of T–S waves on a flat plate with the corresponding results of the classical stability theory in the parallel approximation. An example of calculating the flow around a plate with a rectangular cavity is presented to illustrate the possibility of applying the proposed methodology to nonparallel flows. [ABSTRACT FROM AUTHOR]

Conventionally, Ground Response Analysis (GRA) is carried out using a discrete approach in which a layered soil column is idealized as a multidegree of freedom lumped mass system. In this approach equivalent-linear or nonlinear soil model is used and the soil layers are assumed to be horizontal and infinitely extended. However, when these conditions are not met, the continuum approach to model soil column using finite elements is more realistic. Further, depending on the soil test data availability, the soil model may be chosen as linear, equivalent-linear or nonlinear. When the phenomenon of ground response analysis is numerically simulated, the boundary conditions of the numerical model and the input ground motions play an important role. The present study, aims to compare the results of 1D GRA using discrete and continuum approach. For this purpose ten different real Indian sites are considered and modeled in DEEPSOIL and ABAQUS. The results show a good agreement between the approaches adopted for 1D GRA. This study is a step forward to use continuum approach to carry out 1D and 2D ground response analysis. [ABSTRACT FROM AUTHOR]

As an important part of nonstructural components, the seismic response of indoor water supply pipes deserves much attention. This paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete (RC) frame structure. Different material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic performance. Floor response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions. A seismic fragility study of displacement demand is conducted based on numerical simulation. The acceleration response and displacement response of different combinations are compared. The results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes. [ABSTRACT FROM AUTHOR]

It is shown that the vibration transfer and working medium pressure pulsations through vibration-isolating pipeline junctions of various plants may increase by two or three orders of magnitude with an increase in the vibration frequency and in the presence of incompressible working fluid. The results of research of the found physical models that determine this phenomenon are presented. The experimental results for a spatial three-component broadband active vibration-protection system (AVS) for vibration damping beyond the vibration isolation junction with liquid are considered. An experimental plant scheme for studying the simultaneous spatial active damping of dynamic forces, vibrations and pressure pulsations downstream from the junction has been given. Calculated dependences of the maximum efficiency of considered AVS on frequency are obtained. Efficient active damping of forces is shown to be attainable in an open loop without feedback. While damping in an open loop at the experimental plant, the efficiency of active damping of dynamic forces is obtained in three directions up to 10 dB or more in the frequency range from 5 to 800 Hz (more than seven octaves). The analysis of scientific publications reveals the uniqueness of this result. In this case, there are no zones of negative efficiency outside the active damping frequency range, which appear while using other methods of active damping. [ABSTRACT FROM AUTHOR]

In the article, the earthquakes that occurred in the city of Kahramanmarash on the territory of Turkey on February 6, 2023, with a difference of 9 hours, were analyzed. Based on geological, tectonic, seismogological data, earthquakes in Turkey were analyzed based on the observation network consisting of 57 telemetric seismic stations. According to macroseismic data, earthquakes were felt in 10 regions of the country and in Israel, Iraq, Lebanon, Georgia, Azerbaijan and Armenia. Analysis of source distribution by depth indicated two source zones located between 3 and 30 km depth. The source of the earthquake that occurred on February 6, 2023 is related to the dynamics of the Eastern Anatolian fault, oriented in the northeast-southwest direction. One of Turkey's major tectonic structures, the Eastern Anatolian Fault begins with the Karliova Triple Junction in the north and joins the Dead Sea Fault in the south. As a result of the earthquakes, more than 50,000 people died, 548,777 were injured, and the number of destroyed buildings reached 198,000. In order to determine the strengthening factor of the area, the data of 55 stations were taken from the official website of disaster and emergency (AFAD) and processed with 3 channels using the DIMAS program. Nakamura's method was used. Amplification factor was calculated for that area. Maps were drawn with Arcgis10.6 and Surfer10 programs. It was determined that the amplification factor in the earthquake that occurred at 04:17:35 min 1.8-max 7.8; and in the earthquake that occurred at 13:29:49, the amplification factor was min 1.5-max 9.0. [ABSTRACT FROM AUTHOR]

Currently, the buffeting analysis for transmission lines (TLs) only involves the excitation of horizontal turbulence, while numerous investigations have proven that significant vertical turbulence exists in many wind fields. Additionally, overhead conductors generally exhibit nonlinear behavior, rendering the conventional multidimensional wind-excited model based on linear theories no longer applicable. To address these challenges and avoid relying on the extremely time-consuming nonlinear finite-element method, this paper proposes a closed-form solution (CFS) for predicting time-frequency buffeting responses of TLs excited by two-dimensional turbulent wind. First, the static response is determined through nonlinear static analysis. Then a two-dimensional influence line method, employed to evaluate the turbulent wind effect, is developed by decoupling the buffeting responses in two directions. Power spectral density functions for various responses are further derived, considering the cross-correlation between horizontal and vertical turbulence. Moreover, the impact of wind attack angle on various responses is revealed through parametric analyses. Finally, an amplification factor is introduced to modify the vertical wind effect on equivalent static wind load (ESWL), and the corresponding fitting formula is provided to facilitate the design. Numerical verification illustrates the high accuracy and efficiency of the CFS. Although the wind attack angle is time-varying, it is controlled by the mean wind. As it increases, the RMS of transverse and longitudinal reactions decrease, while the RMS of the vertical reaction increases. Neglecting vertical turbulence underestimates the horizontal ESWL, with the amplification factor exceeding 1.35 when a wind attack angle of 50° is considered. [ABSTRACT FROM AUTHOR]

Although the numerical models can estimate the significant influence of local site conditions on the seismic propagation characteristics near the surface in many studies, they cannot feasibly predict the seismic ground motion amplification in regular engineering practice or earthquake hazard assessment due to the high computational cost and their complex implementation. In this paper, the scattering problem of trapezoidal sedimentary basins, one of the representatives of local complex sites with a relatively small model size, and simplified by practice in this type of study, was selected as the basin model. A series of standard basin models were built to quantify the relationship between the site condition parameters and the site amplification parameters (the peak ground acceleration and the hazard location). In addition, the factors that influence seismic ground motion amplification, such as the basin shape ratio, the soil depth, the basin edge dip angle, the ratio of shear wave velocity between the bedrock and the soil layer, the damping coefficient, and the fundamental frequency, were selected to investigate the sensitivity. A convolutional neural network (CNN) algorithm based on deep learning replacing traditional recursive algorithms was explored to establish a prediction model of basin amplification characteristics. By the Bayesian optimization method, the structural parameters of the CNN predicting model were selected to improve the accuracy of the prediction model. The results show that the optimized CNN models could predict the amplification characteristics of the basin better than the un-optimized CNN models. Three prediction models were established with the site condition parameters as the input parameters and their output parameters were the maximum amplification value of the peak ground acceleration (PGA), the hazard location, and their combination for each basin. To analyze the CNN's prediction ability, each CNN model used about 80% of the data from the seismic model repose results for training and the remaining data (20%) for testing. By comparing the CNN prediction results with the FE simulation results, the accuracy and rationality of each prediction model were studied. The results show that, compared to a single numerical model, the CNN prediction results of the site amplification features could be quickly obtained by inputting the relevant parameters. Compared to recursive class models, the established CNN prediction model can directly establish the relationships among multiple input and multiple output parameters. A comparison of the three kinds of CNN models shows that the prediction accuracy of the joint parameter model was slightly lower than that of the two single-output models. [ABSTRACT FROM AUTHOR]

One-dimensional site response analysis (1D SRA) remains the state of practice to estimate site-specific seismic response, despite the ample evidence of discrepancies between observations and 1D SRA-based predictions. These discrepancies are due to errors in the input parameters, intrinsic limitations in the predicting capabilities of 1D SRAs even for sites relatively compliant with the 1D SRA assumptions, and the inability of 1D SRAs to model three-dimensional (3D) wave propagation phenomena. This article aims at reducing 1D SRA mispredictions using small-strain damping profiles factored by a damping multiplier (D mul) and randomized shear-wave velocity (VS) profiles. An approach for conducting 1D SRAs for site-specific site response assessment is developed to reduce the 1D SRA errors in magnitude and variability. First, sites from a database of 534 downhole sites are classified as 1D- or 3D-like, depending on the substructure conditions inferred from observed transfer functions. Second, data from the 1D-like sites are compared against predictions from 1D SRAs conducted using various trials of D mul and VS standard deviations (σ ln V S ) for VS randomization. Third, D mul and σ ln V S are selected based on their combined ability to reduce the root mean square error (RMSE) in SRA predictions. Results indicate that 1D SRAs conducted with D mul = 3 and σ ln V S = 0. 25 lead to an overall minimum RMSE and thus provide more accurate site response estimates. The use of these parameters in forward SRA predictions is discussed in a companion paper. [ABSTRACT FROM AUTHOR]

Site response estimates from one-dimensional (1D) site response analyses (SRAs) carry inaccuracies due to modeling and parametric errors. Modeling errors are due to the condensation of the three-dimensional (3D) wave propagation phenomenon to the vertical propagation of a horizontally polarized wave through a soil column, and parametric errors are due to the incomplete knowledge of the distributions of soil parameters, leading to the selection of nonoptimal input parameters for a site of interest. While parametric errors are traditionally handled using different soil parameters (e.g. alternative shear-wave velocity profiles), modeling errors are generally neglected. This paper proposes an approach for conducting linear elastic 1D SRAs to improve site response predictions and account for modeling errors. First, ground-motion data from borehole array sites are collected, processed, and screened for appropriateness (e.g. expected shear strains lower than 0.01%, signal-to-noise ratio higher than 3). Second, 1D SRA predictions in terms of transfer functions and amplification factors are compared against observations, and the discrepancies are quantified as residuals. Finally, the residuals are partitioned into a model bias term (c 3 D SRA) , a site term (δ S 2 S s SRA) with standard deviation ϕ S 2 S SRA , and a event- and site-specific remaining residual (δ AMP es SRA) with standard deviation ϕ AMP SRA . Values for c 3 D SRA and ϕ S 2 S SRA for forward predictions are recommended. The sensitivity of the site response residuals to region, site type (1D- or 3D-like), and the applicability of findings to outcropping applications are discussed, and an example application for a hypothetical project site is presented. [ABSTRACT FROM AUTHOR]

Microtremor recording tests using an accelerometer were carried out in this paper with the aim of characterizing the effects of seasonally frozen soil on the seismic site response, including the two-direction microtremor spectrum, site predominant frequency, and site amplification factor. The study selected eight typical seasonal permafrost sites in China for site microtremor measurements during both summer and winter seasons. Based on the recorded data, the horizontal and vertical components of the microtremor spectrum, HVSR curves, site predominant frequency, and site amplification factor were calculated. The results showed that seasonally frozen soil increased the predominant frequency of the horizontal component of the microtremor spectrum, while the effect on the vertical component was less noticeable. It indicates that the frozen soil layer has a significant impact on the propagation path and energy dissipation of seismic waves in the horizontal direction. Furthermore, the peak values of the horizontal and vertical components of the microtremor spectrum decreased by 30% and 23%, respectively, due to the presence of seasonally frozen soil. The predominant frequency of the site increased by a maximum of 35% and a minimum of 2.8%, while the amplification factor decreased by a maximum of 38% and a minimum of 11%. Additionally, a relationship between the increased site predominant frequency and the cover thickness was proposed. [ABSTRACT FROM AUTHOR]

This study of West Nile virus (WNV) examined the possibility of avian transmission to explain synchronicity in the year‐to‐year variability of WNV case numbers from Texas northward to the Dakotas, and reasons for the large case numbers on the northern Great Plains. We determined correlation coefficients between annual disease incidence per 100,000 people among states within the Great Plains Region, as well as the Central Flyway. There was spatial and temporal synchronicity, as evidenced by Pearson "r," with values along the core of the Central Flyway (Oklahoma, Kansas, Nebraska, and South Dakota) varying between 0.69 and 0.79. Correlations for North Dakota (r = 0.6), however, were affected by local conditions. The concept of relative amplification is helpful in explaining why northerly states along the Central Flyway have larger annual case numbers per 100,000 than Texas but preserve the temporal signal. States differed in their capacity for amplifying the temporal signal in case numbers. For example, Nebraska, South Dakota, and North Dakota case numbers were commonly amplified relative to Texas, with Oklahoma and Kansas deamplified. Relative amplification factors for all states increased as a function of increasing case numbers in Texas. Thus, increased numbers of initially infected birds in Texas likely led to the rapid intensification of the zoonotic cycle as compared to more typical years. The study also confirmed the importance of winter weather in locally modulating disease cases. North Dakota appeared most impacted by these factors to the extent of reducing WNV case numbers in colder years and years with deep snow. Plain Language Summary: This study examined factors controlling broad patterns of transmission of West Nile virus (WNV) on the Great Plains of the United States. We found that yearly human case numbers are correlated both temporally and spatially from Texas northward. These findings support the idea that each year migratory birds were important in retransmitting WNV along the Central Flyway with Texas as the source of WNV and North Dakota and South Dakota as sinks. However, states differed in their capacity to enhance the temporal signal. In Oklahoma and Kansas, deamplification in case numbers relative to Texas was common except for the worst WNV years in Texas. For Nebraska, South Dakota, and North Dakota case numbers were commonly amplified relative to Texas. Relative amplification factors for all states increased as a function of increasing case numbers per 100,000 in Texas. These patterns are likely controlled by virulence of the dominant Culex species and local habitat. In North Dakota, the winter climate may also affect human case numbers. Cold conditions reduce populations of over‐wintering mosquitoes and large snow accumulations modulate the springtime return of migratory birds. Such correlations between the local WNV disease cases and these factors may provide a robust, early screening tool for WNV. Key Points: Spatial and temporal synchronicity in human West Nile virus cases was observed along the Central FlywayA consistent pattern of amplification and deamplifications in human case numbers is evident along the Central Flyway as compared to TexasKey factors controlling trends include avian spread, vector competence, and local winter conditions, especially in North Dakota [ABSTRACT FROM AUTHOR]

In the present study, the seismic performances of gravity retaining walls having both inclined back side and inclined backfill were investigated under sinusoidal acceleration excitations using series of shaking table tests on 750 mm height physical model. The effects of input peak ground acceleration (PGA$PGA$), inclination angle of backfill material (α) and inclination angle of back of the gravity retaining wall (β) on acceleration amplification factor (RMSA$RMSA$), maximum peak lateral relative (Smaxpeak(rel)${S}_{{\rm{maxpeak}}({rel})}$) and maximum residual lateral displacement (Smax(res)${S}_{{\rm{max}}({res})}$) of the wall, surface settlement (Sset${S}_{set}$) of the backfill material, inertial force (PI${P}_I$) and horizontal dynamic active force (Pdynh${P}_{dynh}$) were assessed. It was observed that higher values of the RMSA$RMSA$ were obtained from the experimental results as compared the ones from current seismic design codes. Moreover, the six results of shaking table tests revealed that the phase difference was appeared between the inertial force and dynamic earth pressures. Pseudo‐static limit equilibrium methods resulted in over conservative Pdynh${P}_{dynh}$ results and could not truly reflect the seismic behavior of gravity wall due to the inertial forces and phase difference not taken into consideration. [ABSTRACT FROM AUTHOR]

San Salvador Metropolitan Area (MASS) is an urbanized territory in the country of El Salvador, located between the San Salvador volcano and the Ilopango caldera, in a sub-flat area called "Valle de las Hamacas" (Valley of the Hammocks). The high seismicity of this area is due to the subduction zone of the Cocos plate that causes strong seismic events such as the earthquakes that occurred on 13 January (7.6 Mw) and 13 February 2001 (6.6 Mw). As part of the international cooperation project between Italy (AICS) and El Salvador University, the CASTES project focussed on natural hazards in the territory of El Salvador was launched. Therefore, 2D simulations are carried out along two sections to evaluate the Local Seismic Response (LSR) in the Southeast part of MASS territory. Results show spatially variable amplifications (from 3 to 6.5) in the period ranging 0.1–0.7 s and evidence of lateral FA variations that can be calculated only through 2D numerical analyses. Two amplified periods are recognised, 0.1–0.5 s and 0.4–0.8 s, due to the presence of two types of subsoil volcanic deposits: the shallow and soft Tierra Blanca deposits and the deeper and stiffer Volcanic ash and Tuff. [ABSTRACT FROM AUTHOR]

This review paper discusses the procedures for evaluating the design displacement given in various design codes from seismically prone countries around the world (the United States, New Zealand, Chile, Japan, Greece, Italy, Iran, India, Turkey, and Romania). The limit displacements and the corresponding limit states are also presented and analyzed in this study besides the importance class factors considered in the selected seismic design codes. A presentation of the behavior factors necessary for evaluating the design value of the seismic action is also shown in this study. One of the observations of this review paper is that there are significant similarities in terms of the approach to the displacement check in the analyzed codes. In addition, it was observed that the displacement check is generally associated with the serviceability limit state (e.g., damage limitation). However, differences in terms of the mean return period for the serviceability check action were observed among the analyzed seismic design codes. Several aspects which have to be further adapted in the future versions of seismic design codes are also discussed in this review paper. One of the main aspects which must be further discussed is the enforcement of displacement limits, which are dependent on the structural system and on the importance of the class/height regime for the ultimate/serviceability limit state. In addition, the dependence of the TD control period on the probabilistic seismic hazard ordinates should be further discussed. Moreover, the pulse effects, which can affect both the acceleration and the displacement design of response spectra, should be accounted for as well in future generations of seismic codes. Finally, it appears necessary to perform a harmonization of the behavior factors employed in seismic design codes. [ABSTRACT FROM AUTHOR]

Abstract This study of West Nile virus (WNV) examined the possibility of avian transmission to explain synchronicity in the year‐to‐year variability of WNV case numbers from Texas northward to the Dakotas, and reasons for the large case numbers on the northern Great Plains. We determined correlation coefficients between annual disease incidence per 100,000 people among states within the Great Plains Region, as well as the Central Flyway. There was spatial and temporal synchronicity, as evidenced by Pearson “r,” with values along the core of the Central Flyway (Oklahoma, Kansas, Nebraska, and South Dakota) varying between 0.69 and 0.79. Correlations for North Dakota (r = 0.6), however, were affected by local conditions. The concept of relative amplification is helpful in explaining why northerly states along the Central Flyway have larger annual case numbers per 100,000 than Texas but preserve the temporal signal. States differed in their capacity for amplifying the temporal signal in case numbers. For example, Nebraska, South Dakota, and North Dakota case numbers were commonly amplified relative to Texas, with Oklahoma and Kansas deamplified. Relative amplification factors for all states increased as a function of increasing case numbers in Texas. Thus, increased numbers of initially infected birds in Texas likely led to the rapid intensification of the zoonotic cycle as compared to more typical years. The study also confirmed the importance of winter weather in locally modulating disease cases. North Dakota appeared most impacted by these factors to the extent of reducing WNV case numbers in colder years and years with deep snow.

The Liwa area is near the active shear fault of the Sumatra Fault Zone (SFZ), with a right lateral mechanism where the Kumering segment crosses this area. The geodynamic simulation results based on the pre-seismic modeling using the slip rate input of a recent study, Liwa, and its surroundings show a comparatively high compression level. The seismic moment rate estimation based on the present-day surface strain data shows alignment and consistency with the pre-seismic modeling result and the previous correlation dimension (DC) analysis. The high DC indicated that the Kumering segment indicates a relatively high-stress level. The finding also aligns with the suggestion based on the previous result that more frequent large strike-slip earthquakes occur since the recent study found that the slip is faster than the previous one. And it is consistent with the historical records; Liwa has a minimum of 3 times experienced destructive earthquakes, which occurred in 1908, 1933, and 1994. Although based on a deterministic hazard analysis point of view, the zone around the SFZ will experience the most significant ground shaking since it is close to the source. However, the Probabilistic Seismic Hazard Analysis (PSHA) studied around the southern part of Sumatra Island, especially in areas close to the coast boundary, shows that the shaking caused by the source of the subduction and intermediate depth is more frequent than that of the SFZ source. As the city of Liwa is located near the Kumering Segment and relatively close to the shoreline, evaluating the Seismic Hazard Function (SHF) by integrating megathrust, SFZ, and medium depth sources is necessary. The amplification analysis in the previous study using Liwa's HVSR method showed the most considerable amplification value. Thus, this study intends to evaluate the potential for earthquake hazards based on the probability of integrated sources of megathrust, SFZ, and intermediate depth to deep and deterministic based on SFZ sources around the city of Liwa. The earthquake intensity (MMI) estimation at the surface based on the probabilistic to deterministic point of view is in the range of VI to XI. Therefore, it has the potential to reach the maximum MMI scale. The result of this study might be very beneficial in better understanding the future seismic hazard study and mitigation analysis. [ABSTRACT FROM AUTHOR]

In order to evaluate the seismic response of the soils in Puerto Plata city, the lithostratigraphic description of 141 geotechnical surveys was carried out. The Nakamura or H/V (passive seismic) technique was applied to calculate the spectral record between the horizontal components and the vertical by the background environmental noise record. The shear wave velocity (Vs) is determined by the 1D and 2D Multichannel Analysis of Surface Waves (MASW) method (active seismic) at seven sites. PSHAKE software is used for 1D modeling in 26 stratigraphic models. Amplification factors of 0.6 to 2.0 were obtained, with the latter occupying most of the area. The greatest amplifications match with the urbanized part where anthropic materials and Quaternary sediments emerge. [ABSTRACT FROM AUTHOR]

In this study, dynamic centrifugal model tests for two homogeneous saturated soft clay sites are designed to analyze the influence of overlying sea water on ground motion. We obtain the response spectrum value and amplification coefficient from the acceleration sensor records. Through comparative analysis, we conclude that with the increase in input peak ground motion, the acceleration response spectrum value at the same depth gradually increases. When the input peak value is small, there is no significant difference between the response spectra with and without water; when the input peak value is large, there is no significant difference in the high-frequency part of the response spectrum value. In the middle- and low-frequency part, the response spectrum value with water is obviously smaller than that without water. The amplitude of the response spectrum of the water-free model gradually moves in the long-period direction, but the water model tends to the short-period direction. In the long-period part, the amplification coefficient of the water model is obviously smaller than that of the water free model. [ABSTRACT FROM AUTHOR]

Radiotherapy is an important modality for the treatment of cancer, e.g., X-ray, Cs-137 γ-ray (peak energy: 662 keV). An important therapy pathway of radiation is to generate the double strand breaks of DNA to prohibit the proliferation of cancer cells. In addition, the excessive amount of reactive oxygen species (ROS) is induced to damage the organelles, which can cause cellular apoptosis or necrosis. Gold nanoparticles (GNPs) have been proven potential as a radiosensitizer due to the high biocompatibility, the low cytotoxicity and the high-Z property (Z = 79) of gold. The latter property may allow GNPs to induce more secondary electrons for generating ROS in cells as irradiated by high-energy photons. In this paper, the radiobiological effects on A431 cells with uptake of 55-nm GNPs were studied to investigate the GNPs-enhanced production of ROS on these cells as irradiated by Cs-137 γ-ray. The fluorescence-labeling image of laser scanning confocal microscopy (LSCM) shows the excessive expression of ROS in these GNPs-uptake cells after irradiation. And then, the follow-up disruption of cytoskeletons and dysfunction of mitochondria caused by the induced ROS are observed. From the curves of cell survival fraction versus the radiation dose, the radiosensitization enhancement factor of GNPs is 1.29 at a survival fraction of 30%. This demonstrates that the tumoricidal efficacy of Cs-137 radiation can be significantly raised by GNPs. Because of facilitating the production of excessive ROS to damage tumor cells, GNPs are proven to be a prospective radiosensitizer for radiotherapy, particularly for the treatment of certain radioresistant tumor cells. Through this pathway, the tumoricidal efficacy of radiotherapy can be raised. [ABSTRACT FROM AUTHOR]

In this work, we used three finite difference schemes to solve 1D and 2D convective diffusion equations. The three methods are the Kowalic–Murty scheme, Lax–Wendroff scheme, and nonstandard finite difference (NSFD) scheme. We considered a total of four numerical experiments; in all of these cases, the initial conditions consisted of symmetrical profiles. We looked at cases when the advection velocity was much greater than the diffusion of the coefficient and cases when the coefficient of diffusion was much greater than the advection velocity. The dispersion analysis of the three methods was studied for one of the cases and the optimal value of the time step size k, minimizing the dispersion error at a given value of the spatial step size. From our findings, we conclude that Lax–Wendroff is the most efficient scheme for all four cases. We also show that the optimal value of k computed by minimizing the dispersion error at a given value of a spacial step size gave the lowest l 2 and l ∞ errors. [ABSTRACT FROM AUTHOR]

This article presents a finite difference method of order two for stiff differential equation that will overcome the effects of stiffness since it is A-stable. And, reflect the asymptotic behavior of the solution of the stiff problem since it is L-stable. The classical explicit Runge–Kutta methods of order two are not suitable for stiff problems since the numerical solution will not overcome the effects of stiffness and will not reflect the asymptotic behavior of the solution of the stiff problem (for example, Dahlquist problem). And, they are not both A-stable and L-stable. On applying Euler's implicit method, the numerical solution will overcome the effects of stiffness and will reflect the asymptotic behavior of the solution of the stiff problem. And hence, it is both A-stable and L-stable. But it is of order one method. A new numerical method which is both A-stable and L-stable and of order two for the numerical solution of a stiff differential equation is presented in this article. It will overcome the effects of stiffness and reflects the asymptotic behavior of the solution. The new method works well for large values of step size and works well in large domain. The new method is a modified form of the mid-point rule for the stiff problems. The rate of order of convergence is proved to be two both theoretically and numerically. Experimental results show the performance of the method based on the metrics such as stability function, stability region, order star fingers, the rate of order of theoretical and numerical convergence, absolute and relative errors, percentage of numerical solution accuracy and local and global truncation errors both numerically and graphically. [ABSTRACT FROM AUTHOR]