http://localhost:8081/jspui/handle/123456789/113 2026-09-29T10:34:15Z 2026-09-29T10:34:15Z Rastogi, Avichal http://localhost:8081/jspui/handle/123456789/21652 2026-09-21T10:35:21Z 2023-06-01T00:00:00Z

Title: Seismicity Analysis of Nepal Himalaya Authors: Rastogi, Avichal Abstract: The high occurrence of seismic activity in the Nepal Himalaya is primarily a result of the ongoing collision between the Indian continental plate and the Eurasian continental plate. This study focuses on estimating and analyzing the source parameters of earthquakes in the Nepal Himalaya region. The study area, situated in the eastern part of Nepal Himalaya, encompasses the central portion of the Himalayan range. Various tectonic features within the study area, such as the Main Central thrust (MCT) and Main Boundary Thrust (MBT), have been identified and mapped. In this study local seismicity of Nepal Himalaya based on the past data is also discussed. The spatial and temporal distribution of past earthquake data is discussed which shows incompleteness in database for medium magnitude earthquake from 1801-1963. The distribution of earthquakes over time is examined and divided into distinct time periods, including earthquakes that occurred before 1800, those between 1801 and 1963, and those between 1964 and 2015. The characteristics of an earthquake source can be gleaned from its source parameters, which include stress drop, corner frequency, and seismic moment. These parameters are valuable for estimating the intensity of ground motion during earthquakes. In this study, the source parameters of over 100 local events (with magnitudes ranging from 0.1 to 4.2) were estimated using the digital time histories that were available. Using Brune’s model corner frequency and low frequency asymptote are estimated from the spectral method which helps in estimating different source parameters. Between November 2019 and August 2020, the seismographs have recorded 522 events among them only 363 events are located. The events were recorded by a network of digital seismographs. These seismographs are consisted of Triaxial Seismometer and Broadband Triaxial Seismometer. These seismographs were deployed at six stations in the Lesser Himalaya.

2023-06-01T00:00:00Z Ifham, Mir http://localhost:8081/jspui/handle/123456789/21651 2026-09-21T10:34:45Z 2023-06-01T00:00:00Z

Title: Lateral Load Behaviour of Pile Groups Authors: Ifham, Mir Abstract: The use of pile group foundations is widespread in supporting various structures, such as bridges, tall buildings, and offshore platforms. Among the design considerations, the lateral loading capacity of these foundations plays a crucial role in ensuring the safety and performance of the structures. This report aims to investigate the lateral loading capacity of pile group foundations using finite element software, Plaxis 3D Connect Edition V21. The methodology employed in this study involves a parametric analysis by varying key parameters known to influence the lateral loading capacity of pile group foundations. These parameters include the ground slope angle, pile spacing, pile diameter, the L/D ratio of the pile, and the pile head fixity. Prior to conducting the analysis, the accuracy and reliability of the Plaxis model were confirmed by comparing the obtained results with previously published findings. The analysis conducted reveals that the lateral loading capacity of pile group foundations is significantly influenced by the aforementioned parameters. Specifically, an increase in the ground slope angle or a decrease in the pile spacing lead to a reduction in the lateral loading capacity of the foundation. Conversely, an increase in the pile diameter and the L/D ratio of the pile enhances the lateral loading capacity of the foundation. Furthermore, it was observed that the interaction between these parameters can have a notable impact on the lateral loading capacity of the foundation.

2023-06-01T00:00:00Z Lokesh, N http://localhost:8081/jspui/handle/123456789/21650 2026-09-21T10:34:17Z 2023-06-01T00:00:00Z

Title: Pore Pressure Changes Driven Seismic and Aseismic Basal Slip in Glacier Ice Sheets Authors: Lokesh, N Abstract: This study considers the development of basal slip in glacier ice sheets. We consider a simple mechanical model of the glacier ice sheet where a thin deformable thin slab of ice undergoes differential slip at the base. The thin layer deforms in an elastic manner and the friction at the base is considered to be slip-rate and state-dependent. Here we study how a local source of pore water pressure at the base of the glacier could initiate a rapid seismic slip or slow aseismic creep. We explore how pre-pressure diffuses along the glacier base can lead to reduced frictional strength of the interface; and in turn, promotes slip at the base. The model considers three physical processes to simulate the dynamics of the basal slip: (i) elastic deformation of the thin slab of the glacier, (ii) slip rate, and history-dependent (iii) pore-pressure diffusion along the base of the thin slab. We find that the pre-pressure source can alone re-activate slip without any external driving stress. The pre-stress along the fault and pore pressure both dictate the development of slip. The combination of these three physical processes leads to a system of three partial differential equations that govern the evolution of the slip rate, slip state, and pore pressure along the base of the glacier. We numerically solve the coupled partial differential equations method of lines. To calculate the derivatives, we use MATLAB’s FFT subroutine. We find that pore pressure diffusion can lead to rapid slip when basal frictional properties are rate-weakening. The pore-pressure diffusion can lead to slow aseismic creep when basal frictional properties are rate-strengthening. We find that the coupled PDEs governing slip rate evolution ae numerically stiff. For rate-strengthening case, we use similarity solution for pore pressure diffusion and numerical solution for slip rate and state evolution. We find that creep propagation significantly outpaces the pore pressure diffusion regime.

2023-06-01T00:00:00Z Bobbili, Satya Veera Greeshma http://localhost:8081/jspui/handle/123456789/21649 2026-09-21T10:33:55Z 2023-06-01T00:00:00Z

Title: Basin Effects on Ground Motion Characteristics: A Numerical Study Authors: Bobbili, Satya Veera Greeshma Abstract: Basin effects is the entrapping and reverberation of the waves of earthquake in the deposits of soft sedimentary soils atop convex depressions in the underlying bedrock, causing considerable changes in frequency content, amplitude, and duration. In previous earthquakes, this had a significant impact on the duration and severity of the shaking. During the earthquakes, significant disparities in structural damage in the basin relative to surrounding exposed rocks, or even inside the basin itself, were noted. The amplitude of shaking in the basin can be 10 times that of the surrounding rocks. When exposed to ground movements induced by earthquake loading, it is widely known that each soil type behaves differently. In general, depending on geotechnical qualities, depth, and arrangement of soil layers, the soil layers over the hard bedrock may attenuate or enhance the bedrock earthquake motion. The main basin effects are impedance contrast, soil damping, resonance, basement focusing, basin-edge induced surface waves and trapping of waves. The major reason for the cause of various destruction patterns in the basin is edge-induced surface waves. Several numerical studies and experiments have been conducted on the effects of basin edge on the generation of surface waves, influence and characteristics of these waves. The propagation of the seismic waves inside the basin are greatly influenced by the mechanical and geometrical features of the soil in the basin. In the present study, numerical analysis has been carried out using finite difference method to investigate the response of buildings to the BGL-waves. For the simulation of the SH wave, fourth order staggered grid wave FD program given by Narayan and Kumar, 2013 is used for getting response in the rock, homogeneous soil and basin models. The validation of the numerical model has been carried out and the results have been compared with the analytical results.

2023-06-01T00:00:00Z