Shear wave velocity (Vs) is an essential parameter for soil strength and mechanical properties of rocks. Twenty profiles of multichannel analysis of surface waves (MASW), five microtremor measurements, and two geotechnical boreholes have been conducted at the King Saud University site. According to the National Earthquake Hazards Reduction Program classification, the results indicated three distinct layers. The first layer is comprised of silty sand with gravel and thickness ranges of 4-14 m of shear wave velocity (Vs) from 400 to 760 m/s, indicating site C class; the second layer features highly weathered limestone where Vs varies between 760 and 1500 m/s refers B class, while the third layer consists of compact/massive limestone where Vs varies from 1500 to 3500 m/s representing site A class. The bedrock varies in depth from south to north, showing the shallowest depth in the central zone. Moreover, the estimated shear wave velocity and bedrock depth from microtremor measurements agree with MASW results. These results specified distinct weak zones at depths ranging from 2 to 25 m through the study area, emphasizing potential geotechnical concerns associated with these weak zones. Integrating shear wave velocity and microtremor measurements is crucial for advancing sustainable urban development by providing more informed design choices considering local soil conditions. This highlights the significance of geophysical techniques in supporting sustainable development initiatives.

The Taiwan Ground Deformation Index (TGDI) is proposed to quantify site vulnerability using a non-linear soil deformation model, PGA parameters from the Taiwan seismic intensity scale, and microtremor analysis. Site vulnerability is graded into four levels: low (TGDI = 7.4), based on susceptibility to seismic damage. Validating TGDI with 13 disaster events in Tainan during the 2016 Meinong earthquake showed 12 cases of moderate-to-high vulnerability. Since weak ground and strong amplification properties favor TGDI increases, this index serves as an early warning parameter for disasters.

Bhaktapur, lying in the Kathmandu Basin, suffered damages during the 2015 Gorkha Earthquake, potentially exacerbated by local site effects. This research addresses the lack of site response study on Suryabinayak Municipality, located in the southern part of Bhaktapur district. Horizontal to Vertical Spectral Ratio (HVSR) and Floor Spectral Ratio (FSR) methods were employed to determine the fundamental frequencies of soil deposits at 241 free field stations and 20 Reinforced Concrete (RC) isolated buildings respectively. The fundamental frequency of soil deposits varies from 0.27 Hz to 10.00 Hz. Higher frequencies were noted near the basin edges, attributed to shallow sediment deposits, whereas a lower frequencies prevailed towards the basin centre due to an increase in sediment thickness. Out of 20 buildings studied, 7 are highly susceptible to soil-structure resonance as the frequency disparity between building and free-field is less than 15%. This research not only quantified the frequency distribution and soil-structure resonance likelihood but also established a correlation between building height and its fundamental frequency. A significant correlation is observed with a coefficient of determination (R2) value of 60.64% and 83.36% in the longitudinal and transverse directions respectively. The study's results can be endorsed to mitigate seismic hazards, build seismic-resilient structures, and maintain historical monuments.

Noida, located within India's National Capital Region and near the tectonically active Himalayan region, is highly susceptible to seismic activity. Past moderate to high-intensity seismic events emphasize the need for detailed subsurface characterization to enhance seismic hazard assessments. This study investigates seismic site effects in Noida using microtremor measurements and the Nakamura technique to develop spatial distribution maps for seismic amplification, fundamental frequency, and seismic vulnerability index. A total of 129 microtremor data points were collected, with 54 meeting the SESAME criteria for reliable Horizontal-to-Vertical Spectral Ratio (HVSR) analysis. The analysis reveals that the predominant frequency at most sites falls within the range of 0.63-1.10 Hz, indicating the widespread presence of thick, soft sediments in the area. To avoid structural damages caused by the resonance of soil and structure and a table is prepared to showcase the approximate building frequency of various storey in order to avoid soil-building resonance phenomenon. The maximum amplification (A(0)) observed ranges from 4.53 to 5.17 at a few sites, whereas the majority of the study area experiences low to moderate amplification. The calculated seismic vulnerability index (K-g) for the 54 studied locations ranges from 2.27 to 23.60, with higher values found in regions with soft alluvial deposits, identifying them as fragile zones likely to suffer infrastructure damage during an earthquake. Lower K-g values correspond to areas with stiffer substrates. This study provides a preliminary assessment for urban planning and highlights the need for further research into the socio-economic and structural seismic vulnerabilities of the Noida region.

Bengkulu Province, Indonesia, is one of regions prone to earthquake hazards. Daily seismic activity, albeit minor, and imperceptible to humans is common place. Data from the Meteorology, Climatology, and Geophysics Agency reveals an average of eight earthquakes per week. Earthquakes often trigger subsequent disasters such as tsunamis, landslides, and liquefaction. However, liquefaction-related phenomena are often overlooked in researchs, particularly concerning subsurface layers. A notable event occurred on September 12th, 2007, when a powerful 8.6 magnitude earthquake struck Indonesia, causing significant damage, particularly in Bengkulu City. This was followed by a liquefaction disaster in Tanah Patah Village, Bengkulu City. Consequently, the aim of this study is to assess the subsurface conditions in the liquefaction-affected area using geophysical techniques, including microtremor and geo-electric surveys. The data was analyzed to evaluate soil conditions in the affected zone. The resistivity values indicate a predominance of water and sand mixtures at depths of 0 - 20 m (ranging from 1.46 to 15.5 Omegam in Geo_TP-1 and from 4.64 to 15.1 Omegam in Geo_TP-2). These conditions can facilitate processes like condensation and water flow, leading to sand compaction and increase susceptibility to liquefaction. The findings reveal that loose sand dominates the subsurface layers, rendering them highly vulnerable to liquefaction during intense seismic events. Furthermore, the environmental characteristics of the studied area exacerbate its susceptibility to liquefaction. This study provides a comprehensive analysis of soil conditions in the liquefied zone of Bengkulu City.

According to the Mexican National Seismological Service (SSN), about 25 % of Mexico's seismic activity is concentrated in the state of Oaxaca. Overtime, its population has suffered serious material damage and human losses. In the event of an earthquake, the rigidity of the subsoil beneath urban centers directly impacts the amount of damage to buildings and infrastructure. However, because damage is influenced by the soil seismic response and because there are as yet no updated site response studies that allow us to propose a seismic microzonation of the metropolitan area of Oaxaca, research of this type is very useful for educational and governmental institutions. In this study, seismic noise recording was carried out with broadband sensors to characterize the Horizontal to Vertical Spectral Ratio (HVSR). The main outcome of the study is a map representing the distribution of the seismic site response in the metropolitan area of the City of Oaxaca (ZMO). Furthermore, these results were correlated with the study area's soil type records.

The severe damage observed in the Kathmandu Basin, Nepal, during past earthquakes necessitates a thorough study of the seismic behavior of the basin sediments. As the shear-wave velocity is directly related to the elastic shear modulus of the material, it is essential to determine it to incorporate the behavior of the soil in the design of the structure. Hence, we determined average shear-wave velocity in upper 30 m (Vs30) of soil in Bhaktapur district in the eastern part of the Kathmandu Basin at 73 observation points, employing two methods involving the use of non-invasive microtremor array measurements (MAMs). These MAMs are widely used for determining subsurface soil characteristics by analyzing the ambient vibrations of the ground. The first method involves inversion using a genetic algorithm, and the second is a method for obtaining Vs30 directly from the dispersion curve. We found that Vs30 in the southeastern part of the study area was higher than that in other parts. Conversely, Vs30 in the western region was lower. The calculated Vs30 values were used to classify the sites. The elevated eastern and southeastern areas with high Vs30 were categorized as dense soil or soft rock, whereas the areas with low Vs30 that had suffered significant damage during the 2015 Gorkha earthquake were classified as soft soil sites.

Microtremor tests and finite element numerical simulations were used to analyze the seismic ground motion effects of the Yunnan Dayao sedimentary basin. The results of the microtremor relative to the reference point spectral ratio (H-S/H-R) method showed that the spectral ratio curves of each observation point in Dayao basin show multipeak characteristics, indicating that the site consists of different soil layers; the predominant frequencies of each observation point mainly are 6 similar to 9 Hz in the basin and there are lots of differences in the predominant frequencies of different observation points, which indicate that the site stiffness of each observation point is different; the differences of spectral ratios between the east-west directions (EW) and the north-south directions (NS) reveal the site's anisotropy. The amplification coefficient characteristics of each observation point in the basin obtained by numerical simulation show that the predominant frequency is 6 similar to 9 Hz; the amplification coefficients of each observation point are different; the edge effect and the focusing effect amplify the seismic ground motion in the basin; the different amplification coefficients of the two sub-basins reflect the significant effect of the basin soil layers' differences on the seismic ground motion, the site is softer and amplification coefficients are larger; the slope degree of basin edges significantly affects the seismic ground motion near the basins edge, the amplification coefficients of the slope steeper and amplification coefficients larger. This study demonstrates that the microtremor test spectral ratio (H-S/H-R) method has good reliability applied to the analysis of basin effect and combining the finite element numerical simulation method is more effective in revealing the basin effect mechanism.

The single-station microtremor method is one of the fastest, most reliable, and cheapest methods used to identify dynamic soil properties. This study utilizes 49 single-station microtremor measurements to identify the dynamic soil properties of the Hilalkent quarter of the Yakutiye district in Erzurum. Soil dominant frequency and the amplification factor were calculated by using the Nakamura horizontal/vertical spectral ratio (H/V) method. While the soil dominant frequency values varied between 0.4 Hz and 10 Hz, the soil amplification factor changed between 1 and 10. Higher H/V values were acquired with lower frequency values. The vulnerability index (Kg) and shear strain parameters that are utilized to estimate the damage that may be caused by an earthquake were mapped. Especially in the west side of the study area, higher Kg values were observed. The shear strain map was created with 0.25 g, 0.50 g and 0.75 g bedrock accelerations, and soil types that lost elasticity during an earthquake were identified. The average shear wave velocity for the first 30 m (Vs30) was calculated. Finally, it was observed that the western part of the study area, which resulted in a higher period and higher H/V, higher Kg and lower Vs30 values, presents a higher risk of damage during an earthquake.

Various geological disasters, such as landslides and ground movements, occur annually in Srimulyo Village, Malang District, with varying levels of damage. Ground movements can affect structures built above, causing sinking, cracking, and collapse. Research into landslides and ground movements triggered by vibrations is generally conducted using the microtremor method, which has proven effective. This study uses the microtremor method to map the soil condition that is potentially prone to movement or landslides based on the observed soil vulnerability index. Data was collected using a TDL 303s Digital Portable Seismograph instrument; the measurement points were established in the form of a grid distributed across the research area, with a recording duration of approximately 45 minutes at each point. The analysis technique utilizes the Horizontal Vertical Spectrum Ratio (HVSR) based on the Fast Fourier Transform (FFT) principle. The study's results found that the research location's seismic vulnerability index varies between 6.5 and 16.5. Areas with high seismic vulnerability index values, specifically those with Kg>11.5, are scattered on the west, south, and southeast sides of the research location. Based on field observations, these areas are dominated by relatively thick sediment layers, leading to lower dominant frequency values and higher amplification values; consequently, the seismic vulnerability index in the southern region is also high.