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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.

Lateritic soils are widely used in road construction in tropical regions, but their natural engineering properties often require stabilization to meet strength and performance requirements. In Thailand, lateritic soils are commonly stabilized with cement-based binders, which are applied as soil–cement subbase and soil–cement base layers in accordance with the Department of Highways (DOH) specifications. This study evaluates the stabilization of lateritic soil using ordinary Portland cement (OPC) with calcined limestone dust (CLD) as a partial cement replacement. CLD is produced by the calcination of limestone dust, which is a quarry by-product, at elevated temperatures. In the proposed stabilization approach, 20% of OPC was replaced with CLD to assess its effect on the stabilized soil’s physical and mechanical properties. Laboratory tests included Atterberg limits, compaction characteristics (optimum moisture content and maximum dry density), and unconfined compressive strength (UCS). The results indicate that the combined use of OPC and CLD reduces soil plasticity and slightly modifies compaction behavior due to changes in particle packing and moisture demand. Stabilization significantly improves UCS, and mixtures containing 20% CLD achieve compressive strengths comparable to fully cement-stabilized samples after 28 days of curing. Strength enhancement is primarily attributed to cement hydration, which forms calcium silicate hydrate, while CLD contributes through filler and nucleation effects, resulting in a denser microstructure suitable for road base applications.

Indonesia, as a country in the Ring of Fire, has negative impacts in terms of tectonic and volcanic hazards. As an example of an area frequently hit by earthquakes, One of the area in the country frequently hit by earthquakes is the Special Region of Yogyakarta (DIY). Based on the latest studies, a new source has been discovered, which is the east-west trending “fault” called the Mataram or Tambakboyo “Fault”. This “fault” is still in the initial phase of research. This study aims to provide additional information on the Mataram “Fault” from a geophysical point of view, namely by using the gravimetric method. This method provides an understanding of the existence of a fault, namely the indication of a clear contrast difference (order of km) so that the geometry of the Mataram “fault” can be obtained. This parameter will be used in earthquake hazard modeling by using OpenQuake software. It is hoped that with this research, the geometric characteristics of the Mataram “Fault” and the earthquake hazard can be obtained.

Seismicity analysis can be carried out using deterministic and probabilistic methods. One approach that can be done with the help of OpenQuake is the Scenario Seismic Hazard Analysis (SSHA) and Probabilistic Seismic Hazard Analysis (PSHA) methods. The question arises regarding the equivalence between the two methods in producing earthquake acceleration values. In this study, it was tested using a single earthquake source, namely the Lembang Fault. The observed area is in the Bandung Basin area, bounded by mountains on the north and south sides. The method compares the acceleration values (PGA/Peak Ground Acceleration) between PSHA return periods of 500, 1000, 2500, 5000 and 10000 years with SSHA. The results obtained are a value agreement between PSHA with a return period of 5000 years and SSHA. The resulting acceleration (PGA) near the Lembang Fault is 0.5-0.6g.

On the 4 th of June, 2000 and 12 th of September, 2007, Ratu Agung Sub-district, Indonesia experienced significant damage due to liquefaction after the earthquakes. Therefore, this study aims to determine the Liquefaction Potential Index in the area. Data of shear wave velocity (Vs) was collected using the Multichannel Analysis of Surface Wave (MASW) method. The measurement location was set up on a grid of 32 observations points with field investigations. Furthermore, Simplified Procedure and LPI methods were used to measure the soil liquefaction potential and vulnerability level. The results showed that the value of shear wave velocity in the Ratu Agung Subdistrict ranged from 102 m/s to 442 m/s. Also, the liquefaction vulnerability levels varied from high to very high categories due to the maximum soil acceleration and conditions dominated by loose sand, as well as the influence of different geological formations in the zone. In conclusion, an empirical equation was successfully proposed to analyze the liquefaction vulnerability.

Several previous investigations have suggested that ground motion as described by various parameters and resonance effects could have contributed to the damage observed during an earthquake. This paper presents a ground motion parameters study and site investigation in Northern Thailand during the Tarlay Earthquake of 2011. Ground motion parameters recorded at the closest seismic station to the earthquake rupture, i.e. Mae Sai Station (MSAA) are studied. Microtremor measurement was performed at the MSAA site. The horizontal to vertical spectral ratio (H/V) from the investigation are interpreted. Spectral acceleration ratios based on data from the MSAA are compared to determine the possibility of resonance during the earthquake. Spectral acceleration data based on recorded ground motion are compared to guideline design spectral acceleration to determine the critical period. Results show that during the Tarlay Earthquake, significant duration was 24 s. Within this duration, resonance was plausible within the frequency range of 1.82 to 2.1 The critical period ranged from 0.4 to 0.6 s, indicating that low-medium story buildings were most vulnerable. Results also show that horizontal ground motion was relatively dominant in the destruction of structural buildings during the earthquake.

This work presents an application of a simplified energy concept for predicting liquefaction potential based on data collected during the M w 8.6 Bengkulu-Mentawai Earthquake in Bengkulu, City, Indonesia. A total of 38 sites are investigated through seismic data and soil characteristics. One dimensional seismic response analysis is then conducted to determine the peak ground acceleration within each soil layer of the study area. From the peak ground acceleration values, kinetic velocity values are generated. The maximum kinetic energy density due to earthquake shaking is determined using the simplified energy concept. The Empirical analysis is employed to predict liquefaction potential. The empirical analysis results are then correlated to kinetic energy density to generate equations that estimate liquefaction potential in Bengkulu City. Results show that a simplified energy concept can be used to estimate liquefaction potential. The performance of the proposed equations is generally consistent with documented liquefaction cases from around the world, and thus the framework implemented in this study can be adopted to calculate liquefaction potentials in other areas worldwide.

It has been known that Bengkulu City (Indonesia) is vulnerable to undergo seismic damage. This study is initiated by measuring horizontal to vertical spectral ratio ( H/V ) to sites in Bengkulu City using microtremor. The inversion analysis is performed to generate shear wave velocity profile. Hundreds of sites are investigated in this study. The results show that observed H/V is consistent with the theoretical H/V . National Earthquake Hazard Reduction Program code is adopted to classify the site class. The results also exhibit that Bengkulu City is dominated by Site Classes C and D. In general, this study could lead local government to consider seismic hazard mitigation for spatial plan.

Within last 10 years, high intensity of rainfall had triggered the increase of water level during floods along Sub-watershed of Muara Bangkahulu River, Bengkulu, Indonesia. The high rainfall intensity was caused by extreme weather change. This study was focused on a segment of Muara Bangkahulu Sub-watershed called Semarang Segment. This segment is one of socio-economy centres in Bengkulu City. This study was initiated by performing the environmental investigation and collecting the rainfall intensity data in the study area. The site investigation data and soil tests were also performed to obtain the soil properties along sloping ground of sub-watershed. The analysis to obtain the maximum flood discharge as well as the maximum water level within 10 years was conducted. Furthermore, the slope stability analysis using both finite element and limit equilibrium methods was performed. In general, the results of this study could be a recommendation to stakeholders to consider the future impact in the study area. The results of this study could also bring a recommendation for the slope protection in the study area.

This paper investigates the liquefaction hazard in the Port Area of Pulau Baai, Bengkulu City, during the large subduction earthquake of 2007. The study was conducted systematically, commencing with a site investigation that included shear wave velocity measurements. Spectral matching and ground motion predictions, based on a relevant attenuation model, were performed to derive representative ground motions for the study sites. Ground response analysis was carried out to examine soil behaviour under seismic loading. Non-linear finite element analysis was utilised to assess dynamic soil characteristics such as excess pore water pressure, shear stress-strain response and stress paths. Additionally, an empirical evaluation was conducted to assess the liquefaction potential. The results indicate that liquefaction at shallow depths could occur, particularly in the first two sand layers. They also suggest that potential seismic damage could range from VII to IX on the Modified Mercalli Intensity (MMI) scale. Both numerical and empirical analyses demonstrated consistent trends and alignment. The comparison of excess pore pressure ratios and safety factors aligns with findings from previous studies. These results underscore the importance of implementing seismic hazard mitigation measures for the study area.