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On December 18, 2023, an Ms6.2 earthquake struck Jishishan County, Gansu Province, in western China. The China Earthquake Early Warning Network (CEEWN) captured extensive near-field ground motion data using high-density microelectromechanical system (MEMS) sensors and force-balanced accelerographs (FBAs). Through noise level and usable frequency range assessments of MEMS/FBA recordings, we compiled a strong- motion dataset encompassing the Ms6.2 mainshock and 13 aftershocks (Ms >= 3.0). Analysis of this dataset revealed distinct source characteristics and site effects through spatial distributions and attenuation patterns of peak ground acceleration (PGA, up to 1.1 g at station N002B), peak ground velocity (PGV), and spectral accelerations (SAs) across various periods. The mainshock's near-fault motions exhibited pronounced short-period energy, with 0.2 s SAs exceeding 1.0 gin intensity zones VII-VIII due to hanging wall effects, soil amplification, and topographic influences. Site-to-reference ratio (SSR) analysis identified site nonlinearity above 1 Hz and amplification between 1 and 10 Hz. Observed PGAs and short-period SAs surpassed ground motion model (GMM) predictions with faster attenuation rates, while long-period SAs (>1.0 s) remained below predictions. Residual analysis of intensity measures (IMs) and horizontal-to-vertical spectral ratios (HVSRs) demonstrated progressive site nonlinearity, showing HVSR frequency reductions and amplitude declines at PGAs >500 cm/s(2). This dataset advances regional ground motion model (GMM) development, while our findings on strong ground motion characteristics offer critical insights for earthquake damage assessment and post-disaster reconstruction.

期刊论文 2025-07-01 DOI: 10.1016/j.soildyn.2025.109392 ISSN: 0267-7261

Bengkulu city, located in the western part of Sumatra, is characterized by the prevalence of alluvial deposits. In certain areas, local site effects on soft alluvial sediments such as clay, sand, silt, mud, and gravel can amplify ground movements caused by significant seismic waves. Consequently, a comprehensive site effect study was conducted with closer measurement points to establish a more detailed seismic microzonation. In order to evaluate how the soil reacts to seismic activity, the HVSR method is performed to analyze the ambient soil noise within the study area. Field measurements reveal variations in the predominant frequency (ranging from 0.4 to 16.5 Hz), HVSR amplification (ranging from 0.3 to 12.3), and Kg distribution (ranging from 0.02 to 239.26), respectively. Furthermore, the PGA Kanai method was utilized to estimate soil shear strain (GSS) in the study area, using data from the 2000 Bengkulu-Enggano Earthquake (Mw 7.9) and the 2007 Bengkulu-Mentawai Earthquake (Mw 8.4). The analysis indicated a consistent distribution of Kg values with GSS and PGA values, alongside Modified Mercalli Intensity (MMI) values, exhibiting correlation coefficients greater than 0.9. This suggests that Bengkulu City faces a moderate to high vulnerability to severe damage from earthquakes. The closer examination of HVSR data at finer measurement points aids in identifying exposure to new hazards and contributes valuable insights for formulating regional planning policies centered on disaster risk reduction and enhancing existing strategies in Bengkulu City.

期刊论文 2025-06-01 DOI: 10.1007/s10518-025-02168-z ISSN: 1570-761X

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 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 (fp), 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 fp increases. The surface PGA amplification was most pronounced when the fp is close to the site fundamental frequency. Additionally, when fp = 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.

期刊论文 2025-05-21 DOI: 10.1038/s41598-025-02050-7 ISSN: 2045-2322

Prediction of the intensity of earthquake-induced motions at the ground surface attracts extensive attention from the geoscience community due to the significant threat it poses to humans and the built environment. Several factors are involved, including earthquake magnitude, epicentral distance, and local soil conditions. The local site effects, such as resonance amplification, topographic focusing, and basin-edge interactions, can significantly influence the amplitude-frequency content and duration of the incoming seismic waves. They are commonly predicted using site effect proxies or applying more sophisticated analytical and numerical models with advanced constitutive stress-strain relationships. The seismic excitation in numerical simulations consists of a set of input ground motions compatible with the seismo-tectonic settings at the studied location and the probability of exceedance of a specific level of ground shaking over a given period. These motions are applied at the base of the considered soil profiles, and their vertical propagation is simulated using linear and nonlinear approaches in time or frequency domains. This paper provides a comprehensive literature review of the major input parameters for site response analyses, evaluates the efficiency of site response proxies, and discusses the significance of accurate modeling approaches for predicting bedrock motion amplification. The important dynamic soil parameters include shear-wave velocity, shear modulus reduction, and damping ratio curves, along with the selection and scaling of earthquake ground motions, the evaluation of site effects through site response proxies, and experimental and numerical analysis, all of which are described in this article.

期刊论文 2025-04-01 DOI: 10.3390/geosciences15040128

The impact of site effects on ground motion is a critical factor for earthquake disaster prevention and mitigation, as these effects can amplify ground motion and affect building fragility. On February 6, 2023, southeastern Turkey was struck by two strong earthquakes, with magnitudes of Mw7.7 and Mw7.6, followed by numerous aftershocks. These events resulted in severe casualties and substantial economic losses. Field investigations revealed severe damage to mid-rise and high-rise buildings in Kahramanmara & scedil; and Antakya. Both cities are located in valley regions, which are particularly susceptible to earthquake damage due to the amplification of ground motion caused by soft soil conditions and valley topography. In this paper, Horizontal-to-Vertical Spectral Ratio (H/V) technique is used to decipher how site effects affect ground motion and damage using the strong motion records. The analysis revealed that the predominant frequency of ground motion decreases near the valley areas and increases toward the hill slopes. These spatial variations in predominant frequency have significant implications for building safety. Structures located in areas where the predominant frequency matches their natural frequency are more prone to resonance effects, significantly increasing the risk of damage during seismic events. Additionally, the study found that the nonlinearity of the site conditions amplified the acceleration response spectrum at a period of 1 s. This amplification exceeded the local structural design capacity. The findings indicate that site effects can significantly intensify earthquake damage in Kahramanmara & scedil; and Antakya by amplifying ground motion and increasing the vulnerability of mid-rise and high-rise structures.

期刊论文 2025-04-01 DOI: 10.1007/s12665-025-12103-9 ISSN: 1866-6280

The seismic events in Pazarc & imath;k (Mw 7.7) and Elbistan (Mw 7.6) on February 6, 2023, caused widespread damage and destruction across 11 provinces and districts in eastern T & uuml;rkiye. Despite similarities in construction quality and structural stock characteristics, notable differences in the patterns of destruction between the affected cities have highlighted the need for a more detailed investigation. This study focuses on examining local site effects and seismic behavior in residential areas within the impacted zone to better understand the structural damage caused by these earthquakes. Geotechnical data from the affected cities were used as the basis for conducting nonlinear seismic site response analyses. These analyses, using real earthquake records measured in city centers, explored factors such as liquefaction potential, amplification capacity, and the dynamic behavior of soil profiles under seismic loads. Simulations based on actual earthquake records and soil data provided insights into the causes of structural damage in the affected areas during both seismic events. Finally, an evaluation of site effects on structural damage resulting from both major earthquakes was conducted, offering valuable insights through a comprehensive analysis of the results.

期刊论文 2025-03-01 DOI: 10.1016/j.jafrearsci.2024.105463 ISSN: 1464-343X

An earthquake event with a moment magnitude of 7.7 took place in Pazarc & imath;k (Kahramanmara & scedil;, T & uuml;rkiye) on February 6, 2023. Approximately 9 hours after this event, another powerful earthquake event in Elbistan (Kahramanmara & scedil;) with a moment magnitude of 7.6 occurred. This study reports the level of devastation in Kahramanmara & scedil;, Hatay, and Ad & imath;yaman cities of T & uuml;rkiye that were heavily affected. Mainly, the characteristics of the recorded input motions at the affected areas and their spectral accelerations at different sites (possessing different soil classes) along with the design values are evaluated. Moreover, soft-weak story failures and pancake collapses of buildings are discussed together with strong column-weak beam philosophy. The influence of site effect on the input motions and, therefore, on the structural damages is highlighted, too.

期刊论文 2025-01-25 DOI: 10.1080/13632469.2024.2431062 ISSN: 1363-2469

Erzurum province is located close to two important faults, namely the North Anatolian Fault Zone and the East Anatolian Fault Zone. Additionally, numerous local faults such as the A & scedil;kale, Ba & scedil;k & ouml;y-Kandilli, Erzurum-Dumlu, Paland & ouml;ken, and Horasan-Narman Fault Zones could potentially trigger devastating earthquakes for Erzurum province. All these seismic hazard sources require a well-understanding of the soil dynamic properties in Erzurum province. The single-station microtremor method were carried out at 45 points to determine the Atat & uuml;rk University Central Campus-Erzurum soil dynamic parameters with this motivation. Seismic vulnerability index and seismic bedrock depth values were calculated with the help of empirical relations using the soil dominant frequency and soil amplification factor values calculated from the horizontal/ vertical spectral ratio method. The south-eastern region of the study area exhibits characteristics such as low soil dominant frequency values, high soil amplification factor values, elevated Kg values, and considerable engineering bedrock depth. This area is particularly vulnerable to potential earthquake damage due to its high sediment thickness and susceptibility to site effects. Notably, points three and four also demonstrate low soil dominant frequency values, coinciding with the locations of hospitals and administrative units. Therefore, it is imperative to intensify site effect investigations, especially using active sources of geophysical methods in these specific areas.

期刊论文 2024-12-01 DOI: 10.5200/baltica.2024.2.4 ISSN: 0067-3064

The Nilufer district experienced the most recent urbanization among the central districts of Bursa in South Marmara region with the completion of rapid construction. Since 358 BCE, many destructive earthquakes were reported on the branches of the North Anatolian Fault (NAF) which caused extensive damage to buildings and loss of life near Bursa city. Besides some studies conducted to define the soil behavior in the vicinity of Bursa, a seismic hazard study in Nilufer is still lacking. We, therefore, carried out a microzonation study including the following steps. First, an earthquake hazard analysis was conducted and the peak ground acceleration (PGA) values were determined for an expected earthquake. In the next step, MASW (Multi-Channel Analysis of Surface Wave) measurements conducted at 54 points in 28 neighbourhoods of Nilufer district were evaluated. Soil mechanical parameters were determined at 11 boreholes to assess the liquefaction potential. It was found that almost half of the study area suffers from low damage considering only the vulnerability index (Kg) index, which depends on the site effect. Therefore, in addition to the Kg values, we created a microzonation map using the results of soil liquefaction, settlement, changes in groundwater level, and the average values of spectral acceleration. The study area is classified by four damage levels changing from low to high. Using only the Kg index could not quantify the potential damage level in the study area, thus we showed that the districts of Altinsehir, Hippodrome, Urunlu and Alaaddinbey, Ertugrul, 29 Ekim, 23 Nisan, Ahmetyesevi and Minarelicavus were identified at potentially high-risk damage zones. The results of this study clearly showed that considering the Kg index, which depends only on the local site effect, may lead to inadequate damage values.

期刊论文 2024-10-01 DOI: 10.1016/j.jappgeo.2024.105489 ISSN: 0926-9851

An earthquake of Mw = 7.0 occurred on October 30, 2020, in the Aegean Sea near Samos Island, which caused severe structural damage in Bayrakl & imath;, Izmir (T & uuml;rkiye), located around 70 km from the epicenter. To investigate the source, path, and site effects, ground motions recorded in Western Anatolia are simulated using the stochastic finite-fault method based on a dynamic corner frequency approach. The input model parameters are calibrated using the recorded motions at selected 10 stations within an epicentral distance of less than 100 km. The soil amplifications are modeled using horizontal-to-vertical spectral ratios and generic amplification factors. At most stations, including a few within Izmir Bay, amplitudes and frequency contents are modeled closely. Minor discrepancies within particular frequency bands can be attributed to insufficient representation of the local site effects. Finally, distributions of observed and simulated felt intensities are found to be consistent.

期刊论文 2024-10-01 DOI: 10.1142/S1793431124500155 ISSN: 1793-4311
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