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This article focuses on developing a ground motion prediction equation based on artificial neural network (ANN) technique for shallow crustal earthquakes. A hybrid technique combining genetic algorithm and Levenberg–Marquardt technique is used for training the model. The present model is developed to predict peak ground velocity, and 5% damped spectral acceleration. The input parameters for the prediction are moment magnitude (Mw), closest distance to rupture plane (Rrup), shear wave velocity in the region (Vs30) and focal mechanism (F). A total of 13,552 ground motion records from 288 earthquakes provided by the updated NGA-West2 database released by Pacific Engineering Research Center are utilized to develop the model. The ANN architecture considered for the model consists of 192 unknowns including weights and biases of all the interconnected nodes. The performance of the model is observed to be within the prescribed error limits. In addition, the results from the study are found to be comparable with the existing relations in the global database. The developed model is further demonstrated by estimating site-specific response spectra for Shimla city located in Himalayan region.

Estimation of the seismic risk associated with infrastructures requires site-specific seismic hazard studies. Further, for nonlinear time history analysis, one requires broadband ground motion. In modern times, physics-based simulations (PBS) for deriving the ground motion for future earthquakes have been considered. The PBS helps decrease the uncertainties related to hazard estimation compared to ground motion prediction equations. The PBS methods have a specific frequency threshold limit resulting from high computational demand. Hence, hybrid methods are required to attain broadband spectra for the simulated ground motion. This study uses a new artificial neural network (ANN)-based model to generate broadband ground motion spectra using the low-frequency spectral acceleration from PBS, source, path, and site parameters as input variables. A detailed parametric study and performance evaluation was made to identify the optimal input parameters in conjunction with the best-suited ANN architecture. The performance of the ANN model is demonstrated for Iwate (Mw 6.9, 2008) earthquake. We found that the predicted values from the developed ANN model agree with the recorded data. Furthermore, time histories are generated using the spectral ordinate matching technique from the estimated broadband spectra.

For the risk analysis of spatially distributed structures, the joint prediction of ground motion intensities at multiple sites is required. Therefore, many researchers have come up with spatial correlation models for seismic intensity measures (IMs). The spatial correlation model requires site-specific non-ergodic ground motions. One of the chosen approaches for correlation studies is physics-based simulations (PBS), which account for the complexities related to earthquake source, path and site. The present study evaluates the efficiency of the artificial neural network-based broadband response spectra generator (BBANN) of Sharma et al. ( 2023 ) in terms of residual analysis and spatial correlation. The Turkey earthquakes of 6th February 2023 are taken as the case study. The model-predicted values corresponding to a short period are compared with the recorded values for the events. We found that the model was able to capture ground motion trends without any bias in residuals. Also, in the spatial correlation scale, the model predictions are comparable with recorded values. The results highlighted the efficiency of the BBANN model in effectively capturing the spatial pattern of ground motion intensity measures. The study draws attention to the ability of PBS to generate non-ergodic ground motion and, hence, can be useful in seismic hazard and risk frameworks.

Seismic protection of buildings using the Geotechnical Seismic Isolation (GSI) system placed between the natural soil and the building foundation has recently emerged as an innovative and economical alternative to the traditional base isolation system. The present study aims to experimentally investigate the effectiveness of the GSI system composed of horizontal layers of Sand Rubber Mixture (SRM), a high damping energy-absorbing material reinforced with geogrids for seismic protection of mid-rise buildings. A series of 1-g laboratory shaking table tests were carried out on a five-story model framed structure placed on the GSI system in a laminar shear box filled with sand subjected to input excitation of 0.1 Hz to 10 Hz frequency range. The shake table tests were carried out under different base conditions of model structure: (1) pure sand, (2) SRM-GSI system and, (3) geogrid reinforced SRM-GSI system. The seismic performance of the model structure was compared for test beds with and without the GSI system by evaluating and analysing the recorded acceleration-time histories. The results indicate that while both SRM-GSI and geogrid reinforced SRM-GSI system effectively reduces the acceleration response of the buildings; however, the geogrid reinforcement was highly effective in reducing vertical ground settlement and contributing to improved lateral stiffness compared to the SRM-GSI case. The introduction of the geogrid reinforced SRM-GSI system tends to reduce the lateral displacements on the superstructure by 35%, besides minimizing the foundation rotation. In addition, the geogrid reinforced SRM-GSI system significantly reduces the interstorey drift of the model framed structure. Overall, the effectiveness of the geogrid reinforced SRM-GSI system in reducing seismic damages and permanent displacements of typical mid-rise buildings was experimentally demonstrated in the present study.

This article focuses on estimating the seismic recurrence parameters of India and adjoining regions based on a comprehensive catalogue assimilated from various sources. The study region encompasses latitude 0∘ N–40∘ N and longitude 65∘ E–100∘ E. The updated catalogue for the region contained 69519 events, including 28770 mainshocks. The updated catalogue was employed in the estimation of recurrence characteristics of the region. Here, zonal and spatial smoothening-based approaches were employed to estimate seismicity characteristics on a grid of 0.1∘×0.1∘. The active regions like the Himalayas, North-Eastern India, Andaman, and Koyna-Warna regions were observed to have relatively lesser b values indicating the occurrence of larger magnitude events and higher values for activity rate N(4), indicating a more frequent occurrence of an earthquake. The reported values can be further used in seismic hazard estimations for the region

This article addresses the effect of the rupture process on tsunami wave simulations by assessing the propagation of uncertainties from source to wave heights. Thirteen slip models available for the 2004 (Mw 9.2) Sumatra earthquake are utilized in the evaluation. First, quasi-static displacement of the ocean floor is estimated using Okada’s solutions. Further, the corresponding displacement time histories provided as an initial condition for tsunami simulations by modeling the region in Clawpack. The simulated results are compared against the four tidal-gauge data available in the east-coast of India and three altimeter recordings from satellites. The comparisons pointed to the sensitivity of simulated wave heights toward the input slip distribution and rupture process. Further, it is noted from the standard deviations estimated between the results of thirteen models that the value reduced from maximum slip (6.53 m) to displacement (2.60 m), which further reduces in the wave height estimates (1.70 m). Hence, this study suggests the need for proper quantification of the uncertainty propagation in tsunami hazard estimations.

This study presents broadband ground motions for the Indo-Gangetic basin, a large sedimentary basin in India, for potential future great (Mw 8.5) Himalayan earthquakes. We use a recently developed 3D earth structure model of the basin as an input to simulate low-frequency ground motion (0–0.5 Hz). These ground motions are further combined with high-frequency scattering waveforms by using a hybrid approach, thus yielding broadband ground motions (0–10 Hz). We calibrate the 3D model and scattering parameters by comparing the simulated ground motions against available recorded data for two past earthquakes in Himalaya. Our approach accounts for the physics of interaction between the scattered seismic waves with deep basin sediments. Our results indicate that the ground motion intensities exhibit frequency-dependent amplification at various basin depths. We also observe that in the event of a great earthquake, the ground motion intensities are larger at deep basin sites near the source and exhibit an attenuating trend over distance similar to the ground motion models. The extreme ground motion simulations performed in our study reveal that the national building codes may not provide safe recommendations at deep basin sites, especially in the near field region. The period-dependent vertical-to-horizontal spectral ratio deviates from the code-recommended constant 2/3 at least up to 6 s at these sites.

Objective: The satisfaction in a job or work would be depending on many factors like remuneration, work conditions, growth prospects, support for teachers and other related factors. One of the most important such factors as found from the result of much research conducted in this domain is, Work Life Balance (WLB). Introduction: Work Life balance can be described as a measure of the balance that exists between the job and the personal life of an employee. Much study has been conducted in this regard as the clash between personal or family life of an employee and the work is said to affect many other depending factors like performance, output, dedication and morale. Analysis: This study has been carried out among the pharmacy college teachers in Kerala. The study looks into the awareness of teachers about the Work Life Balance policies in pharmacy colleges in Kerala, to determine its effectiveness in implementation, to determine if there is proper balance between Work and personal lives of teachers and to suggest strategies for improvement. Findings: The study identified that a significant number of pharmacy college teachers are not aware about the WLB policies available but they unknowingly are enjoying the main WLB policies such as Flexible hours in general, task sharing&Holidays. Novelty: The various factors affecting the work life balance of teachers like shift work, extra hours, shortage of man power and other related aspects have been marked out in the study and suggestions for improvements like formation of a separate Work Life Balance cell have been put forward.

The present study proposes a methodology to generate stochastic slip field with desired probability structure and spectral characteristics. The characterization utilizes 100 tsunamigenic and 130 non-tsunamigenic slip models available in the SRCMOD database. First, the cumulative distribution function (CDF) of marginal slip distributions is obtained. Then, it compares the estimated CDFs with nine standard distribution functions based on model fitting criteria like Akaike Information Criterion, mean squared error, correlation coefficient, and QQ plots. The analysis showed that the majority of slip distributions follow generalized Pareto or truncated exponential distribution functions. For the parameters of CDF estimated from slip fields, an empirical relation is proposed as a function of magnitude (Mw) to predict the corresponding values. As the next step, to understand the correlation structure of the slip field, semi-variograms are estimated along strike and along downdip for all rupture models considered in the study. A total of nine theoretical variogram models is compared with the semi-variogram of each slip field. From the analysis based on model fitting criteria, most of the slip field is observed to follow a stable variogram model. An empirical equation is developed to predict the sill and range of stable variogram function for a given Mw. Then, an iterative method based on translational field theory is proposed to obtain an ensemble of non-Gaussian slip fields for a given Mw and type of source. The generated sample fields from the proposed method match with the prescribed non-Gaussian distribution and variogram structure. In the sequel, the method estimates the variogram and the corresponding spectral density of the underlying Gaussian field according to translation field theory. The scaling relations and the proposed iterative methodology can be used to obtain an ensemble of possible earthquake slip fields.

The present work aims at building a non-stationary random field model for the slip distribution on the rupture plane. The estimates are arrived based on 230 slip fields available in the SRCMOD database. The evaluation is performed by segregating and quantifying the trend and fluctuation components of the field. Here, the trend portion of the slip is extracted by fitting a 2D elliptical Gaussian surface. The remaining fluctuation part is observed to be stationary following a normal distribution. Further, we propose scaling relations as a function of magnitude for all the unknowns in trend and fluctuation part of the field. Furthermore, an additive model to generate a slip field for a given magnitude combining the deterministic trend part and randomly generated fluctuation part is also developed in the study. Ground motion simulations performed with the components of the slip field showed that the trend portion controls the low frequency, and the fluctuation portion influences the high-frequency characteristics of ground motion. The model developed from the study can be used to generate an ensemble of slip fields for ground motion simulations.