May, 2026 || Volume 30 No.03
Volume 30(3) May 2026 (3-6)
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1
Seismic imaging of coal seams and structural features: A prerequisite for CO? sequestration studies in the Raniganj Basin, India
1CSIR-National Geophysical Research Institute, Hyderabad-500007, India 2Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
3Essar Oil and Gas Exploration and Production Limited, Durgapur-713212, India
4Indian Institute of Science Education and Research Bhopal, Bhopal-462066, India
https://doi.org/10.71122/JIGU.30(3)2026.0016
ABSTRACT
This study presents an integrated seismic and well-based characterization of the eastern Raniganj Basin, India, aimed at imaging coal seams and delineating subsurface structural features, which are essential for evaluating geological CO? sequestration potential. Multiple geophysical datasets, including legacy 2D seismic, high resolution 3D seismic, and 2D multicomponent (2D-3C) seismic data, were analyzed and calibrated using lithological information from drilled wells. The 3D seismic data from the northeastern part of the basin image shallow coal horizons, characterized by laterally continuous and predominantly flat lying reflectors, indicating a structurally less disturbed subsurface. In contrast, seismic interpretation in the southeastern part of the basin, based on conventional 2D and 2D-3C datasets, reveals multiple coal seams, stratigraphic boundaries, and subtle structural features, such as gentle monoclines and minor normal faults. Based on the integrated seismic analysis, the southeastern Raniganj Basin exhibits geological characteristics that are favourable for further evaluation of CO2 sequestration potential compared to the northeastern sector. However, the presence of interpreted fault systems highlights the need for detailed investigations including high-resolution seismic imaging and fault seal analysis, to assess structural continuity and long-term containment integrity. The study establishes a preliminary understanding of the geological framework of the eastern Raniganj Basin that can be further strengthened by integrating high-resolution seismic data with other datasets to quantitatively evaluate storage capacity and long-term containment integrity.
2
Tectonic implications and seismicity triggering during the 2015 Nepal earthquake sequence
Ankush Kumar Ruhela1*, J. Das1, S.C. Gupta1 and Sonu Devi2
1Department of Earthquake Engineering, Indian Institute of Technology Roorkee, Roorkee-247667, India
2Department of Mathematics, Birla Institute of Technology and Science Pilani, Pilani-333031, India
https://doi.org/10.71122/JIGU.30(3)2026.0017
ABSTRACT
An earthquake of Mw 7.8, having an epicenter 80 km northwest of Kathmandu, struck the Pokhara region in central Nepal, causing widespread damage. After 16 days, a second earthquake with a magnitude of Mw 7.3 followed the mainshock. The focal mechanism solution and the distribution of aftershocks indicate that the earthquake occurred on an oblique thrust fault, oriented in a NW-SE direction. In this study, we estimated statistical seismological parameters, including the spatial fractal dimension D-value, the aftershocks temporal decay p-value, the b-value of the G-R relationship, and coseismic stress modelling to analyze the tectonic implications and triggering during this sequence. The sequence had aftershocks of greater magnitude because of the large asperities within the rupture zone, as indicated by the determined b-value of 0.89, which shows that the mainshock struck in a highly stressed zone. The high decay of aftershock activity indicated by the high p-value of 1.10, is likely an indication of a higher value of the surface heat flow. In the fault zone, high heat results in shortened stress relaxation time. A spatial fractal dimension value (D-value) of 2.14, indicates a random spatial distribution and a source of a two-dimensional plane filled with fractures. Using the slip model, the estimated coseismic coulomb stress shows a butterfly-like distribution, and the majority of aftershocks occur in the positive coulomb stress zone. This implies that the majority of aftershock activity has been caused by the transfer of positive coulomb stress as a result of the mainshock's coseismic slip. This also validates that the Nepal earthquake raised the possibility of a large aftershock that occurred on 12 May 2015. For future seismic hazard assessments and risk mitigation in Nepal and the adjacent areas, the estimated results of this study may be helpful.
3
Geophysical mapping east of Closepet Granite in Eastern Dharwar Craton for inferring geology and structure
Santosh Yadav* and Abir Deogharia
Geological Survey of India, Hyderabad- 500 068, India
https://doi.org/10.71122/JIGU.30(3)2026.0018
ABSTRACT
An integrated gravity and magnetic survey was carried out over the eastern margin of the Closepet Granite in the Eastern Dharwar Craton (EDC), southern India, to delineate concealed structural trends and crustal configuration. Ground gravity measurements were acquired using a Scintrex CG-5 gravimeter with DGPS elevation control, and magnetic total field data were collected using a proton precession magnetometer. Bouguer gravity anomalies were computed using standard free-air and Bouguer corrections (? = 2.67 g/cm³), while the magnetic data were corrected for diurnal variations and the IGRF (epoch 2015). The datasets were processed using minimum curvature gridding and Fourier domain filters including analytical signal, tilt derivative, and Reduction to Equator (RTE). Spectral analysis, Euler deconvolution, and joint gravity–magnetic modelling were carried out to constrain source geometry and depth. The Bouguer gravity anomaly map exhibits a total relief of ~33 mGal (–95 to –62 mGal) and reveals a prominent N–S trending gravity high in the central part of the study area. This feature is characterized by steep gradients along its eastern margin and comparatively gentle gradients to the west, suggesting asymmetric geometry. Spectral analysis of gravity data identifies three principal depth levels at approximately 6 km, 3 km, and 1.5 km, indicating a layered upper crustal structure. Euler depth solutions corroborate these estimates and suggest deeper-seated sources in the northern part, compared to the south. The gravity high is interpreted as a laterally extensive three-dimensional crustal body and is considered to represent the probable subsurface extension of the Ramagiri Schist Belt. Associated gravity lows are attributed to lower-density granitic intrusions and structural depressions. Magnetic data, after RTE transformation, reveal dominant E–W to NW–SE trending features, superimposed on the N–S structural fabric. Spectral depths from magnetic data (4.5 km, 3 km, and 1.5 km) indicate that the deepest gravity source lacks significant magnetic susceptibility contrast, suggesting a weakly magnetic basement. Analytical signal and tilt derivative maps clearly delineate structural boundaries and dyke-like intrusions. Euler solutions further constrain shallow magnetic sources aligned along E–W and NW–SE trends. Further, the Joint gravity–magnetic modelling along a 76 km AA? (N–S) profile, constrained by spectral depths, Euler solutions, geological information, and measured density and susceptibility values, confirms presence of a deep N–S trending density-controlled body and relatively shallow magnetically controlled intrusions. Spatial correlation between structural intersection zones and known corundum occurrences suggests additional prospective targets.
4
On the pre-seismic effects of VLF electric field anomalies on the atmosphere corresponding to major shallow seismic events (M = 5.1 - 6.4, depth < 29 km) occurring in India and nearby countries
Ashwani Yadav and Raj Pal Singh*
Department of Physics, GLA University, Mathura-281406, (U.P.), India
https://doi.org/10.71122/JIGU.30(3)2026.0019
ABSTRACT
Observation of horizontal component of VLF electric field data are going on at 3.012 kHz frequency since 24 March 2011 at Mathura station (27.49° N, 77.67° E) by employing a horizontal antenna for investigating the effects of earthquakes. Bulk of the VLF data recorded is analysed using Quartilebased statistical analysis, covering the months of June–July 2015 and February, March and May 2016 in the light of 14 seismic events (M = 5.1 - 6.4, depth < 29 km) that took place in India and countries lying in a circular radius of 1270 km from Chaumuhan, Mathura observatory. Anomalous amplitude enhancements in VLF data were noticed, 1-27 days ahead the onset of the earthquakes that are considered in the present study. Moreover, pre-seismic anomalous amplitude enhancements were found to vary from 0.8 mV to 31.3 mV, and the percentage range of these enhancements varies from 0.95% to 86.22%. The unusual VLF amplitude intensifications are also explored in reference to spurious sources, which include geomagnetic and lightning activities, local building noises, radiations of power lines, and instrumental errors. It is found that the unusual amplitude enhancements are not connected with said sources, excluding the 4 cases of amplitude augmentations with the magnetic storms. To explore the association of VLF amplitude enhancements and their precursory times with earthquakes, probabilities for the pairs of magnitude with VLF amplitude enhancements and precursory time, and focal depth with VLF amplitude enhancements and precursory time, are calculated. Probable values for the aforesaid pairs comes to 84.96%, 88.61%, 81.94% and 92.33% respectively, which are significant and show a correlation of amplitude enhancements and their precursory time with the seismic events. Possible mechanisms for the origin of VLF electric field radiations and their propagation to long distances, are discussed briefly in terms of chemical and acoustic gravity wave channels. Further, following the model given by Sharma and Singh (2022), an attempt has been made to justify the observed VLF amplitude enhancements related to earthquakes using electromagnetic channel.
5
Interlinkages between air pollution and local weather changes in urban environment: A case study from Alwar, Northwestern India
Vivek Kumar1, Divya Prakash1,2* and Swagata Payra3
1Department of Civil Engineering, Poornima University Jaipur, 303905, Rajasthan, India
2Centre of Excellence in Water and Clean Air, Poornima University Jaipur, 303905, Rajasthan, India
3Department of Remote Sensing and Geoinformatics, Birla Institute of Technology Mesra, Ranchi, 835215, Jharkhand, India
https://doi.org/10.71122/JIGU.30(3)2026.0020
ABSTRACT
The air pollution challenge has become a significant environmental and public health issue in the semi-arid urban areas of India. The current study looked at the effect of meteorological factors on the ambient air quality of Alwar, which is a non-attainment city in northwestern India, by examining five years (2018-2022) data of Continuous Ambient Air Quality Monitoring Station (CAAQMS) of the Central Pollution Control Board (CPCB) in Alwar. The parameters of interest are PM10, PM2.5, NO2, SO2, CO, and O3. PM2.5 concentrations ranged from an annual mean of 40.9-52.1 ?g/m3 and PM10 concentrations from 77.5-105.4 ?g/m3; both of which are consistently above the NAAQS. Highest concentrations of particulates were found during winter months with PM2.5 concentrations exceeding 90 ?g/m3 under low wind speed/stable atmosphere conditions. The correlation analysis found a negative correlation between PM, NOx and CO; and positive correlation between O3 and temperature. The drop in pollutants during the 2020 pandemic showed that humans were the dominant contributor to air pollution. Based on these findings, it is concluded that the use of meteorological conditions within air quality management strategies will contribute to improving the air quality in semi-arid urban areas
6
North Atlantic Ocean a visible contributor to Indian summer monsoon rainfall
Vinod Kumar1* and M. Satya Kumar2
1Shyam Bhawan, Ashok Nagar, Road No. 11, Kankarbagh Colony, Patna- 800020, India
26-3-565, Flat No. 301, Akshaya Aparment, Somajiguda, Hyderabad-500082, India
https://doi.org/10.71122/JIGU.30(3)2026.0021
ABSTRACT
Moisture feeding from North Atlantic Ocean saves summer monsoon rainfall over India also during El-Nino, El Nino-Southern Oscillation (ENSO) and Indian Ocean Dipole neutral conditions if cyclonic circulation/flow is observed along North African coast having minimum latitudinal width of 5? south of 25?N during south west monsoon season. Southern Hemisphere Zonal Westerlies Activity Index (SHZWAI), which had been prepared on the basis of (i) combination of High and Low located along 40?S between 40?W-120?E at 850 hPa geo-potential height or vector wind anomaly fields, (ii) a continuous negative anomaly (Low) from 40?S-30?N along 90?E, (iii) a region of negative anomalies lying to the north of positive anomalies (High) along 40?S, (iv) a continuous High from 80?W-150?W or 120?W-170?E, (v) a continuous Low from 80?W-150?W or 120?W-170?E, and (vi) Cyclonic circulation/trough over Arabian Sea in the anomaly of 850 hPa vector wind observed during April-May of the ensuing monsoon year, has been modified for the quantitative forecast of All India Monsoon Rainfall. By considering cyclonic flow and anti cyclonic flow along North African coast up to 25?N over the North Atlantic Ocean during April-May for the period of 50 years (1948-1997), a methodology has been developed for modifying the quantitative forecast of All India Monsoon Rainfall with modified Southern Hemisphere Zonal Westerlies Activity Index. Reanalysed NCEP/NCAR (National Centres for Environmental Prediction/National Centre for Atmospheric Research) data of geo-potential height, vector wind fields and relative humidity at 850 hPa geo-potential height and Sea Surface Temperature of North Atlantic Ocean up to 20?N for the period 1948-2025, have been used in the study. It has been shown that composite anomaly field of vector wind/relative humidity at 850 hPa level for the period April-May from the region bounded by 60?W-100?E and equator to 30?N, are helpful in identifying the conditions that are related to inter-annual variability in All India Monsoon Rainfall .
7
A global review of cloud seeding techniques for rainfall enhancement
Sanhita Shende1,2*, Sudarsan Bera1 and Neelam Malap1
1 CAIPEEX, Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pashan, Pune 411008, India
2Department of Physics, Savitribai Phule Pune University, Pune, 411008, India
https://doi.org/10.71122/JIGU.30(3)2026.0022
ABSTRACT
In a climate change scenario, water scarcity is a big problem for the sustainable development of the society. For this reason, searching for unconventional water resources are of utmost importance in water management. In this context, cloud seeding offers a potential option for alternative water resources, particularly in arid and drought-prone regions, such as the rain shadow zones of Western Ghat mountains in India. Cloud Seeding is a weather modification process (i.e., weather is changed or modified by the artificial mechanism), aimed to enhance precipitation by introducing artificial aerosol particles, which serve as ice nuclei or cloud condensation nuclei, into the naturally formed clouds. This report explores the existing cloud seeding techniques across the globe, inclusive of both glaciogenic and hygroscopic seeding methods. It highlights the specific approaches, target clouds, and cloud seeding experiments employed in different countries, including India, China, United States, UAE, Australia, Thailand, Canada, and others. Our study will be useful to the scientific community in planning of any future cloud seeding projects apart from social awareness related to cloud seeding approaches.
8
Seismic wave attenuation in and around Hyderabad granitic region, south Indian shield
M. Srikanth1*, K. Sivaram1,2 and V. Pavan Kumar1,2
1CSIR-National Geophysical Research Institute, Uppal road, Hyderabad 500007.
2AcSIR?Academy of Scientific and Innovative Research, Ghaziabad, India.
https://doi.org/10.71122/JIGU.30(3)2026.0023
ABSTRACT
We investigate the attenuation characteristics of seismic body waves in the Hyderabad Granitic region (HGR), located in Eastern Dharwar Craton, southern Indian shield, using the coda-normalization method. The analysis is carried out using local earthquake data, recorded by a broadband seismic network of ten stations, installed in and around the HGR. The dataset consists of 30 local earthquakes with magnitudes ranging from 1.4 to 3.9, recorded during the year 2020-2021. Analysis is carried out at five central frequencies 1.5, 3, 6, 12 and 24 Hz for the lapse time window of 40s, to estimate the attenuation parameters for P-waves (QP)-1 and S-waves (QS)-1. In this frequency range, the estimated QP and QS values seem to indicate power-law dependence (Q~Q0fn), where Q0 is Q at 1 Hz, and n is the frequency dependence parameter. QP values vary from 35 ± 15 to 200 ± 80, while QS from 60 ± 10 to 300 ± 150, while ‘n’ shows minor variations for both P and S waves. The ratios QS/QP varying from 0.78 to 2.50, indicate variations in crustal properties, including heterogeneity and fracture characteristics. Our study would be of use in the investigation of the regional seismic hazard, seismic wave propagation and crustal heterogeneity.