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.

Slope stability is an essential aspect of geotechnical engineering. Unstable slopes or stable slopes influenced by external factors may result in a catastrophic disaster called a landslide. In seismically active areas with steep terrain, landslides commonly occur and are regarded as one of the most severe threats. Bangladesh has not suffered any destructive earthquakes in recent years but has a considerable risk of facing such earthquakes owing to its geological conditions. Although slope failures occurring in the Rangamati Hill Tracts of Bangladesh are mainly rainfall-induced, due to the seismic risk in Bangladesh, it is essential to assess earthquake-induced slope failure in vulnerable areas. In this study, the authors analyzed the seismic slope stability at three locations in the Rangamati Hill Tracts using pseudostatic approaches. The pseudostatic approach with the variation in seismic force based on the seismic coefficient was utilized to determine the critical conditions. Using Newmark’s rigid block method, the permanent displacements for various slope conditions were calculated for the Kobe earthquake. The analysis provided crucial insight into the state of the locations. One location has a low factor of safety (FS) value at a slope angle of 30° or greater, whereas the others have a risk of slope failure at a slope angle of 50° or greater. Newmark’s displacement analysis also showed that the slopes at location 3 have the highest displacement at a lower slope angle, with location 1 and location 2 showing relatively better results than location 3. Structural and bioengineered preventive measures are needed in this area to reduce the vulnerability of possible slope failure.

Bangladesh is a South Asian country with a dense population situated in a very vulnerable position of earthquake faults where sudden earthquakes can cause a great loss of lives and properties. This paper deals with the magnitude and focal depth of earthquakes that have been felt from 2015 to 2019 having Richter magnitude more than 3. Maximum earthquakes with a magnitude of 3.0 to 4.9 have occurred at the northern side of Bangladesh whereas at the eastern side the values are between 4.0 to 5.9. It was seen that considerable earthquakes occurred in 2019 at the northern side of Bangladesh that indicates a major earthquake may happen in this area from the stored energy and can cause a devastating effect. It has been observed that Earthquake with more than 3 Richter magnitudes has happened in all five years in February, April, August, and September where January and December have comparatively fewer earthquake records. Focal depths have been found to be higher in 2016 related to other years. A correlation equation has been developed between magnitude and focal depth.

Before reaching the ground surface, the amplitude, duration and frequency content of the vertically propagating seismic waves can be modified by the local stratigraphy and soil physical properties. In this study, we evaluate the impacts of the soil shear wave velocity (V_s) and thickness (H) on the seismic ground response using 1D ground response analysis. Simplified soil profiles typical for the Saguenay Lac-Saint-Jean region (SLSJ) are considered defined with relatively thin glacial sediments overlaid by more than 100m thick marine sequence. Impedance contrasts exist at the bedrock interface and between the fine marine and glacial sediments. Time-domain nonlinear 1D numerical simulations are carried out with Deepsoil®. The seismic input at the bedrock level is defined with synthetic earthquake time histories compatible with eastern Canadian seismo-tectonic settings. It is found that the changes in the Fundamental period of the soil caused by changes in the thickness of the soil deposit and soil V_s have a significant impact on the surficial amplification.

Detecting landslides and unstable slopes is one of the most crucial responsibilities in the emergency response to resist landslides. Having a wide range of hilly terrines in the southeast region of Bangladesh, the risk of landslide disasters is becoming a critical issue. In Chittagong, especially in the Rangamati hill tracts, there have been several losses of life and property due to landslides in the recent past. This research attempts to evaluate the landslide risk in Rangamati hill tracts and provide suggestions to mitigate the landslide hazard by modifying the hill slope. Soil specimens from different hill locations were collected from three areas in the Rangamati district. Several laboratory experiments were conducted to determine the soil properties, and 2D slope stability analysis using Bishop's simplified method was used to evaluate the landslide potential. Different preventative measures, for example, soil nailing, anchors, and cutting slopes like stairs, are also implemented to mitigate the landslide potential by increasing the slope stability was assessed and suggested. Weighted Overlay Model (W.O.M.) was implemented for the Landslide Susceptibility Analysis in ArcGIS to confirm the potential hazard in the study areas, and hazard maps were suggested based on the slope stability results and current slopes in Rangamati. The slope stability analysis of the three spots showed that spot 3 is the most vulnerable spot, which had a low factor of safety value. Even with different mitigation techniques, spot 3 showed a lower factor of safety value, which was verified with the Weighted Overlay Method. It was also seen that among the mitigation techniques, anchoring the slopes is the most effective one that drastically increases the factor of safety value.