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.

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.