Browsing by Author "Singh, A.P."

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    Evaluation of site-specific characteristics using microtremor measurements in the Gorakhpur city of Uttar Pradesh, India
    (Springer, 2021) Shankar, Uma; Yadav, Pawan Kumar; Singh, A.P.; Gupta, Arun Kumar
    The microtremor measurements are carried out in and around the Gorakhpur city (Uttar Pradesh), India, overlain by alluvium at about 150 sites to understand the local site conditions. Horizontal-to-vertical spectral ratio (HVSR) confirms that the majority of sites have a predominant frequency of ~0.45 Hz, which may suggest the prevalence of thick soft sediments in the area. Conspicuously, a number of multiple peaks in HVSR curves at few sites may reflect the presence of different interfaces with significant impedance contrasts. Maximum amplification is observed of 4.0�5.3 to the NW�SE of the city, whilst few sites in the city are found to be associated with different values of peak amplification factor that varied between 2.0 and 4.0. It is also observed that the ground vulnerability index (Kg) in Gorakhpur city has values higher than 10.0 at most of the sites. Assimilation of 1-D velocity model for the city clearly shows that low shear wave velocity (~300 m/s) down to the depth of ~35 m, suggesting thick piles of sediments that may correspond to fluvial river system in the area, whilst the peak frequency of about 0.45 Hz may correspond to the Quaternary�Tertiary sediment boundary that may exist at deeper layers (~1000 m). The inference of this study may be used as inputs for earthquake risk management by reducing the severity of earthquake shaking through design of earthquake risk resilient structures. � 2021, Indian Academy of Sciences.
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    Mental Health Questionnaire (MHQ) for Managers: Development and Standardisation
    (Sage Publications India Pvt. Ltd, 2022) Gupta, V.K.; Singh, A.P.
    Nowadays mental health is being fundamental concern to human being, while work is an integral part of modern life. Mental health is an important psychological attribute that plays a determining role in increasing the performance of employees and reducing rate of absenteeism, tardiness, and turnover of employees in the organisations. Our aim was to explore the psychometric properties of the newly developed questionnaire related to mental health. The items were framed with help of the previously available tools and interaction with sampling unit. Initially, 56 items were constructed related to the emotional, psychological and social well-being, eliminating jargons and complex terms defining the dimensions and its underlying statements so that newly developed questionnaire could be used in variety of workplace settings and items were framed to fit the manager�s context. Only 42 items were retained on the basis of experts� maximum agreement and this 42-item questionnaire was distributed to participants to take their responses. The sample comprises of 250 managers of first level working in different units of Coal India Limited. The results of reliability analysis indicate that Cronbach�s alpha =.896 after deleting the 15 items from the questionnaire due to poor corrected item total correlation, less loadings and cross loadings in exploratory factor analysis. The reliability statistics fit the optimal level of Nunnally�s criteria and statistically acceptable for newly developed questionnaire. Results of the exploratory factor analysis indicate that these 27 items are loaded on three factors and these three factors explain 42.623% of total variance in mental health. This questionnaire will be useful for assessment of mental health of managerial personnel. � 2021 SAGE Publications.
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    Microtremor measurements in the India's holy city, Varanasi for assessment of site characteristics
    (Elsevier Ltd, 2021) Shankar, Uma; Kumari, Sangeeta; Yadav, Pawan Kumar; Singh, A.P.; Gupta, Arun Kumar
    Microtremor measurements are used for preliminary site effect of the Quaternary sediments of Varanasi in Indo-Gangatic plain, which is being planned as a Smart City of India. We evaluated site effects using single and arrays Microtremor measurements at various sites in the Varanasi City, Uttar Pradesh, India. At City, H/V spectral ratios using microtremor measurements indicate fundamental frequency range 0.37�0.63 Hz, corresponds amplification 5 to 14 times. This indicates that the deep thickness of the upper soft soil at about several hundreds of meters. Such huge amount of sediments deposition sources could be associated with fluvial rivers system in the area and sediment drain from Himalaya. The average peak frequency (~0.5) may reflect the Quaternary-Tertiary boundary. Microtremor array measurements at two sites were taken using circular arrays (30 and 60 m) which consists of three recording stations on the circumference of circle and one in the centre of circle. The Phase velocity dispersion of Rayleigh wave is calculated from array using SPAC method, and a 1-D shear wave velocity structure is determined by means of inversion processes. The top layers up to 50 m show shear velocities between 280 and 320 m/s and the velocities of underneath layer vary between 1500 and 1600 m/s till 100 m of depth. These results from the present study would be useful for future planning purposes as well as risk management and to reduce severity of earthquake effects in the study area. � 2021 Elsevier Ltd and INQUA
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    Numerical modelling of tsunami wave to assess the possible impacts along western coasts of India
    (India Meteorological Department, 2023) Dani, Babita; Srivastava, Vaibhava; Singh, A.P.; Bhatla, R.
    Numerical modelling of tsunami waves has been made for the western coasts of India using TUNAMIN2 code. In this study, the fault parameters are considered from earlier published literatures. Bathymetry data and possible tsunami generation locations have been obtained from the ETOPO2 (Global Relief Model) and General Bathymetric Chart of the Oceans (GEBCO) satellite data. For tsunami run-up the land topography data Shuttle Radar Topographic Mission (SRTM) is used. The present simulation consists of a duration of 6 hours (360 min). Possible arrival times with amplitude at various locations have been estimated. The paper also analyses the changes in the directivity of the generated tsunami waves towards the western coasts of India by changing the dip and strike angles as different scenarios. Time series and height along the different parts of Gujarat coast and hourly travel-time chart of the tsunami waves are also discussed. After the earthquake and initial tsunami wave generation, it reached all the locations along the Gulf of Kachchh (Gujarat) in nearly 2 hrs to 5.30 hrs with amplitudes from 1 to 2.5 m, Mumbai in around 4.45 hrs with amplitude of 2 m, Goa in around 3.08 hrs with amplitude 1 m, Karwar (Karnataka) in around 3.12 hrs and Mangalore in around 3.36 hrs with amplitudes 1 m each. The authenticity of the estimated tsunami phases of the 1945 tsunami genic earthquake along the Makran Subduction Zone (MSZ) are corroborated with the available reports and published literatures. � 2023, India Meteorological Department. All rights reserved.
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    Study of Local Site Conditions for Seismic Hazard Assessment at the BHU Campus, Varanasi, North India, using Ambient Noise Measurements
    (Springer, 2022) Kumari, Sangeeta; Singh, A.P.; Shankar, Uma; Pratap, Birender; Gupta, Arun Kumar
    The ambient noise measurement approach has been applied for detailed seismic hazard mapping in the Banaras Hindu University (BHU), campus, Varanasi. Thirty three single stations, two standard penetration tests (SPT), and two array micro tremor measurements were carried out to determine the local site characteristics. In this study, H/V spectral ratio confirms that the sites have an average predominant frequency of around 0.53Hz and an average amplitude of 7.94. These resonant frequencies are related to the thickness of the sediments in the region. Based on the available lithological data and estimated sub-surface structures, shallow and deeper cross-sections through two profiles within the BHU campus are presented. The estimated shallow sub-surface structures are correlated with 150 m boreholes data for a better understanding of sub-soil stratification. These studies show the presence of clay up to a depth of ?40 m, mixed with sand and pebbles at some locations, followed by layers of sand, and clay with pebbles ?200 m. Findings of the present study are also well correlated with inverted shear wave velocity profiles. The Vs observed from the array measurements and N-value from standard penetration test (SPT) are positively correlated to each other and give a better understating of Vs. Thus, the inverted 1-D shear velocity models clearly show low shear wave velocity having sediment thickness of 30 to 40 meters. Finally, fundamental frequency, amplification, vulnerability index, and shear wave velocity maps are presented. Additionally, the borehole data are used to calibrate the results of the present study of the shallow sub-surface structure. Subsequently, computed maps are a very useful tool for engineers to quantify the intensity of earthquake ground motion, which will be helpful to determine the capacity of buildings to resist earthquakes. � 2022, Geological Society of India, Bengaluru, India.
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    Tsunamis in the Past and Recent Years over Indian Coasts: A Review
    (Springer Science and Business Media B.V., 2023) Dani, Babita; Srivastava, Vaibhava; Singh, A.P.; Bhatla, R.
    The deadliest tsunami prior to 2004 in South Asia was on November 27, 1945, of Mw8.1, which originated off the Makran coast of Pakistan in the Arabian Sea and caused deaths as far as Mumbai. Tsunami characteristics associated with the west coast of India are studied in detail here to understand the tsunamigenic hazard along coastal regions of Gujarat, India. After the deadly tsunami of 2004 in the Indian Ocean, many scientists and geologists over the world started studying the two possible tsunamigenic earthquake zones [i.e., Makran Subduction Zone (MSZ) and Andaman-Sumatra Subduction Zone (ASSZ)] in detail to assess the cause, vulnerability (of coastal areas), and proper preparedness and mitigation against such natural hazards. Therefore, a detailed study of these vulnerable subduction zones is much needed because it is beneficial in planning the protection measures to counter inundation and damages caused due to tsunamis and also in the proper execution of an early warning system. A much needed and reliable catalog of tsunamis in the Indian Ocean and tsunamis that affected the west coast of the Indian region and vicinity have been assessed to study the tsunami hazard. In view of this, the present study deals with the study of seismic gaps in the subduction zones along MSZ and ASSZ that could give rise to large tsunamis in future. And also, tsunami travel times, wave height, run-up, and possible inundation scenarios have been summarized. � 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.