In the present study, an attempt has been made to develop a modified genesis potential index (GPI) by considering the atmospheric parameters of relative humidity (RH), thermal instability (TI), relative vorticity (RV), vertical wind shear (WS) and the ocean parameters of sea surface height (SSH) and upper ocean heat content (UOHC). The new genesis potential index (GPI) is a modified version of the

Abstract A total of 45 seafloor sediments procured from shelf-slope region off Chennai–Cuddalore in the Bay of Bengal and analyzed for ostracod population revealed the presence of 41 species in 30 genera. Based on the results, the dominant species include Cushmanidea spp., Actinocythereis scutigera, Caudites javanus, Neomonoceratina iniqua, Spinoceratina spinosa, Stigmatocythere spp., Tanella gracilis

This study focuses on the impact of varying landfall timing in a tidal cycle (i.e., the spring-neap phase) and varying wind speeds (i.e., cyclone intensities) on the surge tides for the tropical cyclone Fani in the Bay of Bengal using a hydrodynamic finite element-based 2D (ADvanced CIRCulation) ADCIRC model setup. For atmospheric forcing, the Cyclostrophic Symmetric Holland wind Model (H80) and Generalized

Fractures are the prominent deformation-induced structural features that develop in the rocks under brittle regime. Establishing a relationship between structural development and paleostress orientations is thus necessary to propose the comprehensive tectonic models of the study area. The study area lies in Lesser Himalaya (LH), which is restricted by the Main Central Thrust (MCT) in the north while

Much of the time, geological data are not accurately known. Instead, geoscientists work with a range of possible data. These data can have a range since they can vary spatially and temporally. In this context, we demonstrate how a well-established structural geological model of velocity profile of ductile simple shear, expressed as an equation, can be furthered by fuzzy set concept. The implementation

The present study focuses on determining the best combination of microphysics (MP) and cumulus parameterization (CP) schemes for the simulation of Tropical Cyclones (TCs) in the Indian subcontinent region, using the Weather Research and Forecasting (WRF) model. From the available schemes, four CP schemes, namely Kain–Fritsch, Betts–Miller–Janjic, New Simplified Arakawa–Schubert, and Grell–Devenyi,

We used 57Fe Mössbauer spectroscopic measurements on untreated and controlled thermally treated Ararki, Didwana, and Bhawad ordinary chondritic meteorites to understand the evolution of different iron phases with temperature. The samples were subjected to different heating temperatures and room temperature Mössbauer spectra were collected after cooling down these samples. The untreated meteorite samples

The vast unexplored lateritic terrain of Kabirdham District, Chhattisgarh has received attention due to the presence of localized bauxite mines. In the present study, the ASTER images are processed to demarcate the ore, based on the spectral features of boehmite, gibbsite, and goethite in the VNIR–SWIR electromagnetic domain. This approach delineates the target and helps us to pinpoint the potential

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

Research highlights Delineated groundwater potential zones by a weighted overlay analysis based on conventional method with 110 electrical resistivity surveys and 40 lithological data. MODFLOW was used to calibrate and validate the flow pattern and characteristics of groundwater. Groundwater potential map was validated with specific capacity and MODFLOW results were validated with pumping test results

The Almora nappe in the Kumaun Lesser Himalaya (KLH) is mainly composed of Saryu Formation, Gumalikhet Formation and Cambrian felsic intrusives. Zircons from a paragneiss, exposed near Kwarab along Sualbari–Almora transect, of Saryu Formation, are subjected to U–Pb geochronology in order to delineate the timing of tectono-thermal events and its implication on pre-Himalayan orogenic cycle. Zircon rims

Research highlights The frequency-dependent shear-wave quality factor and site amplification are computed simultaneously for the Garhwal region, NW Himalaya. A regional quality factor relationship of form, Qβ(f) = (102 ± 3.9)f(1.0±0.1) is established for the Garhwal Himalaya. The acceleration records corrected from the obtained site effect are used to develop attenuation relations at each recording

Abstract This study intends to scrutinise the style and mechanism of the avulsion events in the Torsa River flowing across the Himalayan Foreland Basin (HFB) through analysing its response to the topographic and hydrological controls. A scientific investigation has been done planting the major thrust on the process geomorphological approach with an obligatory amount of quantification of the process

Full waveform inversion (FWI) is a powerful yet computationally expensive technique that can yield subsurface models at high resolution. Randomly selected shots (mini-batches) can be used to approximate the misfit and the gradient of FWI, thereby reducing its computational cost. Here, we present a methodology to perform mini-batch FWI using the Adam algorithm, an adaptive optimization scheme based

Abstract In this paper, we present a modified version of the Pereyra–Rosen algorithm to the solution of ill-conditioned linear and nonlinear inverse problems arising in gravimetry. We perform a sensitivity analysis of the solution to the two main tuning parameters of this algorithm, comparing its solution with LSQR and the truncated SVD. First, we show the application to a general-purpose linear system

This study investigates presence/absence of homogeneity in 32-yr (1981–2012) rainfall record of four individual monsoon months (June–September) and monsoon season (JJAS) for 16 stations in Saraswati River basin, Gujarat, India. Temporal homogeneity is examined by Hartley, Link-Wallace, Bartlett, and Tukey tests, and spatial homogeneity is tested by Levene’s and Tukey tests. Coefficient of variation

Research highlights Similar fluctuations in the time derivatives \(dH/dt\) and \(dD/dt\) of the geomagnetic field components were observed in the horizontal components \(Ey\) and \(Ex\) of the geoelectric field and the GIC variations. The disturbance fluctuations in the geoelectric field components and the GIC exhibit higher amplitudes during the daytime, especially between about 8:00 and 16:00 LT

A scientific expedition was carried out onboard RV Sindhu Sadhana (12th to 23rd February, 2020) for gas hydrate/cold-seep exploration in Mannar basin, northern Indian Ocean. We observed for the first time gas flares in the water column images of the multi-beam echo-sounder off Mannar basin. Water sampling was carried out by using CTD through the gas flares to understand the nature and distribution

Thirty-eight new apatite and zircon fission-track ages from 26 bedrock samples vary from 2.0 ± 0.3 to 12.1 ± 1.2 Ma, and 3.3 ± 0.3 and 13.2 ± 0.7 Ma, respectively, along three transects of the Kurung, Subansiri, and Siyom Rivers, which flow across the major structures of the Arunachal Himalaya. These cooling ages reveal marked variations in millennial-scale (>105 yr) exhumation rates from 0.6 to 3

The Paleoproterozoic Aravalli Supergroup exposed in the Zawar Pb–Zn mineralized belt of Rajasthan, India contains a mixed siliciclastic–carbonate horizon (Mochia Formation), which hosts the mineralization. The mixed sediments are underlain by a siliciclastic turbidite unit (Mandli Formation) and overlain unconformably by a fluvio-deltaic- to storm-influenced siliciclastic platformal deposit (Bowa Formation)

The characterization of the reservoir rock's geomechanical properties is critical to address wellbore instabilities and subsidence-related issues. To address these issues, lab-derived dynamic and static elastic properties are essential to match the in-situ rock properties. In this study, as part of a new integrated workflow P-wave and S-wave velocities are congregated using ultrasonic transducers for

Research highlights This is the first geochemical work ever done for the shales of Neoproterozoic Chhaosa Formation of Simla Group, Lesser Himalaya. K2O/Na2O vs. SiO2/Al2O3, TiO2 vs. Al2O3, and Zr vs. TiO2 binary diagrams of the studied shales indicate felsic source rock. High CIA, CIW, A–CN–K and Al2O3 values of Chhaosa shales support intermediate to strong weathering of source rock. K2O/Na2O vs.

Abstract The accumulation trends of Cu, Zn, Pb and Ni and their effects on two native species, Etroplus suratensis and Villorita cyprinoides from Cochin estuary and their biomarker responses were explored. Bioaccumulation and metal selectivity index (MSI) in E. suratensis for gill and liver showed the highest accumulation for Zn (209.33 ± 17.14 mg kg−1) followed by Cu (64.16 ± 8.07 mg kg−1), while

Abstract We studied the growth and evolutionary history of four major volcanoes of the Tharsis Province based on morphometry, age and hypsometric studies. Shield volcanoes of Tharsis volcanic province demonstrate marginally dissimilar landform evolutionary trends. Arsia Mons is distinct with a single caldera of large diameter and showed the highest asymmetry in the apron development. A convex hypsometric

Precipitable water vapour (PWV) is estimated using GPS data collected from the continuous operating reference station (CORS) located in Dehradun city, a valley in northwestern Himalayan region. PWV is also estimated using two well-established IGS stations observations in India to validate the retrieval process and to investigate PWV variation over these locations. Meteorological observations, required

Contamination of potentially toxic metals (PTMs) can be detrimental to ecological processes, diversity and physiology of biological components of the surrounding habitat of estuarine and coastal environment. In our study, an inclusive approach to measure ecotoxicological parameters was followed considering spatial concentration of PTMs in the sediment system, sediment quality status, ecological risk

Determining an oceanographic parameter on regular grid positions, using a set of data at random locations both in space and time, is the most sought after typical problem since long in the field of oceanography. This is usually called the gridding problem, and the outcome is useful for many applications such as data analysis, graphical display, forcing or initialization of models, etc. In the present

Abstract The insight of this study focuses on extracting significant controlling factors contributing to the deviations of groundwater chemistry in suburban district of western Uttar Pradesh. Q-HCA based grouping of the sampling sites categorized major ions chemistry into moderately mineralized clusters (Cluster 1, 2) and highly enriched clusters with exceeding mean levels for the majority of parameters

Abstract The Meso-Neoarchean Kudremukh greenstone belt (KGB) of Western Dharwar craton comprises predominant metabasalts associated with banded iron formations (BIFs). The metabasalts are characterized by moderate MgO (7.23–8.97 wt.%), Ni (48–374 ppm), Cr (33–188 ppm) with a wide variation in \(\sum \)PGE (21.8–215.7 ppb) contents with 15.8–115.9 ppb Pd, 3.7–105.2 ppb Pt and 0.7–8.5 ppb Rh. Among IPGE

El-Nino Southern Oscillation (ENSO) is a major ocean–atmospheric coupled phenomenon in the Tropical Pacific Ocean that influences the Indian summer-time temperatures during April and May. In the current analysis, we examined the impact of ENSO on Indian heat waves. Temperature zones are identified when the maximum temperature exceeds 42°C, particularly during April and May over the Indian subcontinent

Abstract The stability of slope is usually characterized by many parameters which are mostly uncertain in nature. Deterministic approach is usually followed to calculate the factor of safety of a slope, but it does not depict the true state of the slope. Hence, a probabilistic approach is a better alternative, which can quantify the probability of failure of a slope under uncertain input parameters

Abstract Erosion along Kavaratti Island has intensified in recent times due to infrastructure development and natural phenomenon. Numerical models were used to identify suitable foreshore protection structures, considering the near-shore coastal processes. For this purpose, shoreline change around the island was obtained from field surveys and results of the DSAS model. Subsequently, model simulations

Tropical cyclones are the most devastating weather events which still needs to understand much due to the uniqueness in their paths and intensification locations. One such recent very severe cyclonic storm, Titli, is perfectly fit for the individual case study. The cyclone Titli originated from a low-pressure area formed over the southeast Bay of Bengal (BoB) and adjoining north of the Andaman Sea

The benthic foraminiferal abundance and diversity for the last ~145 kyr at ODP Hole 723A in the northwestern Arabian Sea have been analyzed to better understand the factors responsible for the changes in the strength of Oxygen Minimum Zone (OMZ). The decline in the abundance of dysoxic taxa and more diverse fauna during interstadials of MIS 5 (5.5 and 5.1) along with higher percentages of G. bulloides

Abstract Neoarchean migmatized granodioritic gneisses and mafic enclaves from the Madras block of the Southern Granulite Terrain (SGT) were studied to understand their genetic relationship. The gneisses show calc-alkaline trend, more magnesian than tonalites, enrichment of LILE and LREE with HFSE depletion, and zero to slightly negative ɛNd values (t=2600 Ma) which indicate their precursors fractionated

Abstract Barren Island volcano (BIV), India has started erupting vigorously from 2018 after a gap of 13 years (last active period 2004–2005) just after the 2004 tsunami. Although there is evidence of coupling between seismicity and earthquake in this region, it is not thoroughly researched. Here, we present satellite-based approach to monitor and understand the volcano dynamics w.r.t. associated seismicity

Research highlights Compared performance of absorption decomposition algorithms in optically complex waters. Good performance of absorption decomposition algorithms in inherent optical property retrieval from the measured total absorption coefficient. Limited applicability of absorption decomposition algorithms in longer wavelengths. Higher errors in total absorption coefficient derived from semi-analytical

In this study, we present the geochemical analysis on 14 samples from seven distinct E–W trending mafic dykes from the Chotanagpur Gneissic Complex. These dykes have not been studied previously and highlight the importance of igneous and tectonic processes in the Chotanagpur Gneissic Complex. The dykes, in terms of modal mineralogy, do not show notable variations, but textural variations are well noticed

The nationwide lockdown in India to curb the spread of Coronavirus disease 2019 (COVID-19) led to colossal reduction in anthropogenic emissions. Here, we investigated the impact of lockdown on surface ozone (O3) and nitrogen dioxide (NO2) over a tropical coastal station – Thumba, Thiruvananthapuram (8.5°N, 76.9°E). Daytime as well as night-time NO2 showed reduction by 0.8 (40%) and 2.3 (35%) ppbv,

This study aims to explore the variation of Chlorophyll-a (Chl-a), particulate organic carbon (POC) and sea surface temperature (SST) before (pre-cyclone) and after (post-cyclone) the cyclone Amphan in the Bay of Bengal (BoB). Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua satellite level-3 data were used to assess the variability of the mentioned parameters. Chl-a concentration was observed

Understanding the anatomy of drought is important to reduce the drought hazards in arid and semi-arid regions around the globe. This study pertains to disclose the spatio-temporal variability of rainfall over the Kashmir region in all four seasons of a year (winter, spring, summer, and fall) along with Mann–Kendall trend analysis to provide a preferable insight into the rainfall excess and deficit

Abstract Kanara Batholith is an intrusive granitoid pluton into the basement biotite-gneisses and the supracrustal rocks of the Western Ghats Belt (WGB). The pluton is situated in the western margin of the Western Dharwar Craton (WDC). These granitoids are classified as granodiorite and granite based on their field and petrographic characteristics. Based on the abundance and presence of alkali-feldspar

Abstract Comparison of chlorophyll data of three sets of CMIP5 models for RCP 4.5 (MPI-ESM-MR, HadGEM2-ES and GFDL-ESM2M) and RCP 6.0 (IPSL-CM5A-LR, HadGEM2-ES and GFDL-ESM2M) were done with satellite derived data (OC-CCI) for the period of 1998–2017 along four Indian coastal regions. The monthly, yearly and zone-wise seasonal comparison between model and satellite data were carried out. Analysis of

The western Indian volcanic rifted margin, and its large-scale tectonic feature called the Panvel flexure, formed at 62.5 Ma during the late stages of Deccan Traps flood volcanism. We present a geological account of late-stage (≤ 62.5 Ma) Deccan volcanism and plutonism in the relatively poorly studied Thane–Vasai region in the Panvel flexure zone. The study area shows west-dipping basaltic sequences

We present here the paleointensity results of basalt samples from Rajmahal (25.10°N; 87.40°E) and Sylhet Traps (25.22°N; 91.71°E) of eastern India (~117 Ma) to know the strength of the earth's magnetic field during the early Cretaceous from these locations. The modified version of the Thellier–Thellier paleointensity method of, in field-zero field-zero field-in field (IZZI) protocol and systematic

In the recent past, there were extensive floods in the Western Himalayan region (WHR) due to continuous long spells of heavy rainfall for 3–4 days that caused a huge loss in life and property over the region. WHR is a data sparse region, with limited meteorological stations having a continuous long spell of daily precipitation data. In the present study, spatial and temporal variability of seasonal

Abstract The Sundarbans Estuarine System (SES), comprising the southernmost part of the Indian portion of the Ganga-Brahmaputra delta bordering the Bay of Bengal, is India’s largest monsoonal, macro-tidal, delta-front estuarine system. The Sundarbans Estuarine Programme (SEP), covering six semi-diurnal tidal cycles during 18–21 March 2011 (the Equinoctial Spring Phase), was the first comprehensive

Abstract A detailed lithostratigraphic, bulk organic geochemical and palynofacies analyses were performed on organic-rich shale and coal samples from the Hettangian Datta Formation in the western Salt Range, southern Potwar Basin, Pakistan, to evaluate its hydrocarbon generation potential. Organic matter (OM) in the formation is mainly dominated by gas-prone Type III kerogen and oil- and gas-prone

Abstract Kerala, located in the southwest part of India experienced heavy flooding during 2018. A post-flood field survey was conducted by National Centre for Coastal Research (NCCR), Chennai to study the flood. The survey was conducted using in-situ measurement and fed to NCCR-Geo surveyor app. The app is indigenous and transfers the data including flood depth and geo-tagged photos to NCCR server

The perturbation produced in the atmosphere/ionosphere associated with earthquake precursors during seismic activity of two major earthquakes which occurred on (1) 24 June 2019 in Indonesia (M = 7.3) and (2) on 19 August 2018 at Ndoi, Fiji (M = 8.2), are studied. Based on statistical analysis of total electron content (TEC) data, the presence of ionospheric perturbations 5 days before and after the

This study presents a recent estimate (for year 2017) of ice thickness and volume of a small glacier called Patsio Glacier located in Western Himalayas. Also, the present study aims to examine whether the improvement in GlabTop2 based estimates obtained for Chhota Shigri Glacier through the use of relatively accurate and high-resolution Digital Elevation Model (DEM) and glacier specific model parameterisation

The N–S trending Neoarchaean to Palaeoproterozoic Dongargarh–Kotri belt in the Bastar Craton in central India exposes bimodal volcanics and volcaniclastics of the Nandgaon Group. In this contribution, lithofacies analysis of the Nandgaon Group has been attempted mainly based on distribution of rhyolites, basalts and pyroclastics in this ancient volcanic terrain, their field characteristics and petrography

Extraordinary multi-seasonal episodes like El Niños of 1982–1983 and 1997–1998 and their widespread teleconnection effects have spurred varied investigations on the changes in sea surface temperature (SST) variability in the post-WWII period. Most of them have been region-specific. We investigate here change in the variance of SST anomaly (SSTA) in the world oceans from 1951–1980 to 1981–2010. Our

Knowledge of relations among ocean biogeochemical and cloud properties will help to plan experiments necessary to understand the mechanisms and processes underlying the links between ocean and atmosphere interactions. Here, we explored the associations between ocean biogeochemical and cloud properties in a region that seasonally experiences polluted and pristine atmospheric conditions in winter and

Abstract The rocks of Raialo Group in the Alwar sub-basin of North Delhi Fold Belt were investigated with a focus on meta-basic lava flows of the Tehla Formation. The basaltic rocks, now occurring as amphibolites, are medium- to fine-grained and show evidence of greenschist to lower amphibolite facies metamorphism, characterized by dominant plagioclase, hornblende, actinolite, chlorite, and minor,

Abstract A protocol is presented to perform bulk magnetic susceptibility (BMS) analysis of simulated seawater/saline water using MFK2-FA Multi-Function Kappabridge instrument at Laboratory for Analyses of Magnetic and Petrofabric (LAMP), BHU to obtain a correlation between BMS and hydrogeological data such as salinity and conductivity. This LAMP-BHU Protocol involves the preparation of simulated saline

Shunkalpa Glacier, union of two glaciers namely Kalabaland (10 km long) and Yankchar glaciers (9 km long), is one of the largest glaciers in the Central Indian Himalaya with snout records available since 1886. We aimed to provide a comprehensive status of the glaciological characteristics of the glacier from satellite-based observations by providing the status of the snout fluctuation, surface velocity

The mineralized (U bearing) rocks, near Bangurdih area, in the western part of the Singhbhum shear zone (SSZ) are strongly deformed and metamorphosed. The host and country rocks are mylonitic in nature with strong linear and planar fabrics. Surface studies indicate that the mineralized bodies are discontinuous in nature and occur sporadically. The thickness of the individual mineralized bodies is also

The proportion of blue carbon contribution by benthic fauna with regard to climate change issue is a relevant topic recent times. The present study is focusing on the carbon potential and blue carbon contribution of meiobenthic nematodes in the intermediate zone of Arctic Kongsfjord during 2015–2017 and the study is the first of its kind from this region. Foraminifera and Nematoda were the dominant