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.

The purpose of seismic microzonation has always been to estimate earthquake ground motion characteristics on the ground surface based on available geological, seismological and geotechnical data. During the early years, mostly geological data and observations from past earthquakes were used to prepare microzonation maps. In more recent years, regional earthquake hazard studies, geotechnical investigations, and site response analysis became more common. The uncertainties in source characteristics, soil profile, soil properties, and the characteristics of the building inventory can be considered as critical issues associated with these analyses. In the first stage, the probabilistic distribution of the related earthquake parameters on the ground surface may be determined considering all possible input acceleration time histories, site profiles, and dynamic soil properties. Generally, to account for the variability in earthquake source and path effects it is suggested to use more than 20 acceleration records compatible with the site-dependent earthquake hazard. Likewise, more or equal to 100 soil profiles generated by Monte Carlo simulations may be used to account for the variability of site conditions. Then the seismic microzonation in a specific area may be based on the probabilistic assessment of these factors in site response analysis. An attempt will be made to briefly review the past, present and possibilities for future studies on microzonation applications.

Landslides are recognized as major natural geological hazards in the mountainous region, and they are accountable for enormous human causalities, damage to properties, and environmental issues in the Teesta River basin, Sikkim, India. GIS approaches are widely used in landslide susceptibility mapping (LSM) that can help relevant authorities to mitigate landslide risk. The binary logistic regression is applied to estimate the landslide susceptibility zonation (LSZ) in the upper Teesta River basin areas. The landslide inventory data are subdivided into training data sets (70%) for applying algorithms in models and testing data sets (30%) for testing model accuracy. The LSZ mapping is designed after analyzing multicollinearity test of 14 landslide CFs and the result shows that the VIF value is less than 10, and TOL is greater than 0.1, respectively. There is no multicollinearity for the 14 conditioning landslides factors. The upper Teesta River basin is categorized into five groups: very low-to-very high landslide susceptibility zones. The results highlighted that most of the middle and southern parts of the study region are highly prone to landslides compared to the other parts. The susceptibility of landslide in the upper Teesta River basin areas validated by performing the Receiver Operating Characteristics (ROC) curve, which showed an 83% confidence level. The present research demonstrated landslide vulnerability circumstances for the Teesta River basin, Sikkim, an area prone to landslides, emphasizing the need for an effective mitigation and management roadmap.

Comprehensive assessment of liquefaction potential is an important aspect of understanding the liquefaction susceptibility and risk of any region. In India, liquefaction potential assessment (LPA) was carried out as a part of seismic microzonation, and a lot of research work has been reported for major cities/regions. A review of LPA for major cities/regions in India was presented in this study for better understanding of the factors considered in the assessment. In addition, a comprehensive LPA considering the susceptibility, probability, and associated seismic risk on existing structures was evaluated for eight sites in Roorkee region, India. The factor of safety against liquefaction (FSL) and liquefaction potential index (LPI) are evaluated using existing standard penetration test (SPT) data. Also, liquefaction probability (PL) and post-liquefaction settlement (SL) are theoretically estimated to frame a comprehensive LPA. This study is the first of its kind to frame a comprehensive LPA considering both the susceptibility indices (FSL and PL) and liquefaction damage indices (LPI and SL). The results indicate that a high risk of liquefaction and surface manifestations are possible for the selected sites for considered seismic scenario. Fines content and the number of borehole layers are critical in influencing the resistance to liquefaction and surface manifestations. Estimation of SL from SPT N number and volumetric strain approach were found in good agreement with the interpretations obtained from the LPI values. It can be stated that for any design of structures against liquefaction, FSL must be higher than 1.20, as this can be evident from the available literature and the presented case study of Roorkee region.

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.

Landslides are significant geological hazards in mountainous regions, arising from both natural forces and human actions, presenting serious environmental challenges through their extensive damage to properties and infrastructure, often leading to casualties and alterations to the landscape. This study employed GIS-based techniques to evaluate and map the landslide susceptibility in the Bekhair structure located within the Zagros mountains of Kurdistan, northern Iraq. An inventory map containing 282 landslide occurrences was compiled through intensive field investigations, as well as the interpretation of remote sensing data and Google Earth images. Ten potential influencing factors, including elevation, rainfall, lithology, slope, curvature, aspect, LULC, NDVI, distance to roads and rivers, were selected to construct susceptibility maps by integrating the frequency ratio (FR) and analytical hierarchy process (AHP) approaches, with the goal of understanding how these factors relate to landslides occurrence. The Bekhair core area was divided into 5 hazard zones on the landslide susceptibility maps. The regions classified as very low and low hazard zones are mainly occur in flat or gently sloping plains that characterized by resistant rocks, dense vegetation, minimal rainfall, shallow valleys, and are distant from riverbanks and roads. The areas designated as high and very high hazard zones are found in steep slopes and rough terrain with bare soil, intense weathering, high rainfall, sparse vegetation, highly fractured rocks, deep valleys, and close proximity to construction projects. The moderate hazard zones are mainly located between the other 4 zones across the Bekhair anticline. Results of the susceptibility analysis indicate that the occurrence of landslides in Kurdistan mountains are primarily controlled by factors related to the tectonic structure, surface characteristics and environmental conditions, such as rock lithology (competency), terrain slope, rainfall intensity, and human impacts. The delineation of landslide hazard zones offers important guides for government decision-makers engaged in regional planning, infrastructure development, and the formulation of strategies to mitigate landslides and protect lives and properties in Kurdistan. The accuracy of susceptibility maps was evaluated using the R-index and the AUC-ROC curve. The landslide susceptibility index (LSI) values allocated to different susceptibility classes derived from both FR and AHP models are consistent with the values obtained from the R-index. Moreover, the FR model demonstrated superior performance compared to the AHP model, with a success rate of 85.3% and a predictive rate of 81.2%, in contrast to the AHP model's success rate of 75.2% and predictive rate of 72.4%.

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.

Local site effects play a vital role in determining the level of structural damage to the structures built on soil. Therefore, correctly determining the underground layer structure and its physical characteristics in the lateral and vertical directions is essential for the geotechnical model. More information and more accurate results will be obtained if the geotechnical model is evaluated multidisciplinary together with geophysical studies, not only based on drilling results. For this purpose, vertical electric sounding, seismic refraction, microtremor, and mechanical drilling techniques were applied within the scope of geotechnical studies in the & Idot;neg & ouml;l district of Bursa. The methods were evaluated together, and the geotechnical cross-sections of the underground were interpreted. In addition, microzonation maps determined from Geophysical parameters were created in the study area. These maps, geotechnical cross-sections, and microtremor data evaluation results predicted how the study area's buildings and soils would behave under dynamic forces such as earthquakes. As a result, the soils in the study area were mainly saturated with water and had weak strength. Existing or newly constructed engineering structures on such soils are predicted from microzonation maps that will damage both the soils and the buildings in a seven-magnitude earthquake.

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.

For the last few decades, for the liquefaction susceptibility assessment of a location, Standard Penetration Test (SPT) based methods have been generally practiced. In this research, the liquefaction potential of Dhaka Metropolitan Development Plan (DMDP) area has been analyzed using three existing Cone Penetration Test (CPT) based methods. CPT (CPTu and SCPT) data have been collected from 546 locations of the DMDP region covering 1530 square kilometer area and have been analyzed to assess the liquefaction potential. Bangladesh is located in the junction of Indian and Eurasian plate, which makes this country vulnerable to earthquakes. A magnitude 7.5 earthquakes and Peak Ground Acceleration (PGA) value of 0.21 g at the surface have been used to evaluate the liquefaction susceptibility of the region using the three CPT-based techniques and another CPT-based technique has been employed to evaluate the liquefaction susceptibility of the region using variable surface PGA based on Modhupur scenario. Liquefaction potential maps have been proposed and compared for these four methods. It has been found that more than 60% of the study area falls within the LPI range which indicates moderate to relatively high liquefaction vulnerability. The liquefaction susceptibility of the three methods has been found to be in agreement and possible reasons of deviation in any particular method have been explained. Also, Ishihara 1985 proposed LPIISH has been estimated and compared with Iwasaki's LPI values. It has been observed that the difference in results using LPI and LPIISH are not significant. The seismic microzonation and liquefaction analyses will help engineers, planners and relevant professionals to get prior idea about the seismic vulnerability of any part of the DMDP region and take measures beforehand to avoid any damaging consequences.