Gravity Datasets Research Articles

Quantifying Crustal Growth in Arc‐Backarc Systems: Gravity Inversion Modeling of the Lau Basin

AbstractThe formation and evolution of arc‐backarc systems govern crustal production in some of the most volcanically and hydrothermally active environments on Earth. This study presents the first complete three‐dimensional density model of the active arc‐backarc system in the southwest Pacific comprising the Lau Basin and Tofua arc. Seafloor density and crustal thickness maps reveal changes in crustal composition and growth rates throughout the basin and along the volcanic arc. Crustal thickness varies significantly between the different centers of accretion (i.e., assemblages), resulting from seafloor spreading and subsurface melt accumulation below volcanic fields. Volumetric growth rates were calculated for each assemblage, corresponding to their respective contribution to basin expansion. The highest crustal density and growth rates are thought to be related to a mantle‐derived melt source entering the basin from the north around the edge of the subducting Pacific Plate. This study shows that the inverse modeling approach can be applied to global gravity data sets to characterize and quantify the density and thickness of the crust anywhere in the oceans.

Evaluation and homogenization of a marine gravity database from shipborne and satellite altimetry-derived gravity data over the coastal region of Nigeria

Abstract Accurate geoid modelling in marine areas requires the integration of gravity data from multiple sources including shipborne gravity measurements, global geopotential models, and satellite altimetry-derived gravity data. This study aims to develop homogenized gravity data for the coastal region of Nigeria to improve geoid modelling accuracy. Residual linear drifts in the shipborne gravity dataset from the Bureau Gravimétrique International (BGI) were corrected using crossover adjustments for each survey leg. We eliminated gross errors for each survey leg by using the 2-sigma method. Outliers in the historical shipborne gravity data were identified and removed using the leave-one-out cross-validation technique, resulting in a refined shipborne gravity dataset. The refined shipborne data were compared with the gravity data predicted by DTU21GRA, SSv29.1, SGG-UGM-2, XGM2019e_2159, GECO, EIGEN-6C4, and EGM2008. Our findings show that DTU21GRA outperformed the other models in the same region when compared with shipborne gravity data. The refined shipborne gravity data were merged with the DTU21GRA data using Least-Squares Collocation (LSC) to create a combined gravity dataset. The results of comparison between the complete refined shipborne gravity data and DTU21GRA before and after the integration process, shows that both the mean offset and the SD values decreased from 0.43 to −0.02 mGal and 3.14 to 2.69 mGal, respectively, which reveal an improvement in the final combined data. The geoid model constructed using the combined gravity data before and after the integration process showed an improvement in the SD values, decreasing from 0.023 m to 0.016 m when evaluated against the CNES-CLS22 MDT.

Inhomogeneous Magnetization of Tyrrhenian Seamounts Revealed From Gravity and Magnetic Correlation Analysis

AbstractWe perform a joint analysis of gravity and magnetic data sets in the Tyrrhenian Sea region to infer the rock physical properties of several volcanic seamounts. We propose a moving‐window application using Poisson's theorem, which relates the total gradient of the magnetic field to the total gradient of the first‐order vertical derivative of the gravity field data. In volcanic environments, where strong intensity of remanent magnetization is expected, the total gradient of the magnetic field is particularly useful since it is almost independent on the direction of the total‐magnetization. The moving‐window approach resulted necessary due to the heterogeneous magnetization distribution of the volcanoes. First, we perform synthetic tests based on realistic seamount models which exhibit inhomogeneous magnetization intensity and orientation. Using the total gradients, we demonstrate that our approach can provide an appropriate magnetization‐to‐density ratio in different subareas of seamounts. The results of the correlation analysis for the Palinuro, Marsili, Vavilov, and Magnaghi seamounts provide interesting information on the variability of magnetization associated with different epochs of formation and demagnetization effects due to hydrothermal alteration processes.

Moho depth model of South America from a machine learning approach

Crustal structure models play an important role in the characterization of seismogenic zones, in the regional delimitation of geological provinces and particularly, in understanding the genesis and evolution of sedimentary basins. Despite the increasing number of new seismic surveys and seismographic networks in South America, crustal thickness measurements are still scarce and irregularly sampled, reducing the resolution of crustal model maps. To overcome these challenges, a novel approach based on machine learning techniques is proposed, in order to explore higher resolution gravity datasets in the interpolation of crustal thickness measurement points obtained from previous seismic/seismological compilations. The algorithm used in this study is based on Gaussian processes prediction methods, which allowed inferring the depth of Moho to South America. The prediction error of the model obtained from the training and testing database was 3.48 km, which is compatible with the uncertainties derived from the H-k stacking analysis. The depth range varied from 69.8 km beneath the Andes to 4.3 km in oceanic regions. The average Moho depth for the South American Platform is 39.1 km, allowing a spatial correlation of deeper and shallower Moho regions with different types of continental basins. Compared to other models, the model resulting from this study presents fine-scale features highlighting the limits of the main tectonic domains and a good agreement with the suture zones. Overall, this study demonstrates the potential of applying machine learning tools in crustal-scale imaging using sparse datasets, providing new advances in Moho modeling of the South America, as well as new perspectives on its the history and tectonic evolution.

Eigen-6c4 Gravity and Alos Palsar Radar Data Integration for Delineating Geological Lineaments in North Ghadames Basin, NW Libya

Introduction The ambiguity regarding the geological interpretation has the potential to be significantly decreased with the use of remote sensing, geophysical data, and the history of geology. Aims The objective of this work is to delineate geological lineaments and faults using EIGEN-6C4 satellite gravity and ALOS PALSAR radar data in the north Ghadames basin, of northwest Libya. Methods The satellite gravity dataset of the study region was used to perform a complete Bouguer anomaly map of the study area to start the gravity interpretation. Then different filters were performed on the gravity dataset, such as the total horizontal gradient (THG), CET grid analysis, 3-dimensional Euler solution (ED), and a tilt derivative (TDR) using the commercial Oasis Montaj programme. The techniques of edge identification (THG, TDR, and also CET grid analysis) are utilised for locating and identifying the boundaries or edges of geological structures that contribute to gravity anomalies. The 3-dimensional Euler solution, in conjunction with the TDR method, is employed to precisely figure out the positions and estimated depths associated with subsurface sources. Radiometric calibration, speckle filtering, and geometric correction were applied to preprocess the ALOS PALSAR L 1.1 image via the Sentinel Application Platform (SNAP) software. For automatic extraction, the PCI Geomatica software's LINE module was applied. Results The gravity data results indicate that the main trends of the identified geological lineaments are oriented in the North-South, East-West, Northwest-Southeast, and North-Northwest to South-Southeast directions. Furthermore, the depths of the sources observed underneath the study region differ from 250 m to 2750 m. The orientation of extracted lineaments from the ALOS PALSAR L1.1 images, specifically the horizontal-horizontal as well as horizontal-vertical polarisation images, predominantly have orientations in the north-south, north-northeast to south-southwest, east-west, north-northwest to south-southeast, and northeast-southwest directions within the study area. Conclusion All these findings of lineaments are associated with the tectonic features of the area. Consequently, identifying these lineaments/faults is important to reduce the ambiguity of geological interpretation and provide more information on the dominant trends for future exploration activities in the study region.

Advancing potential field data analysis: the Modified Horizontal Gradient Amplitude method (MHGA)

Enhancing the detection accuracy of the edges of the geological features within the subsurface remains a significant objective in geophysical data interpretation. Despite numerous advancements, approaches stemming from the directional gradients of gravity and magnetic fields still grapple with challenges such as low-resolution outcomes and susceptibility to noise contamination. In this study, we introduce a novel filtering framework based on the total horizontal gradient and its derivatives, designed to yield more precise and coherent edges free from false boundaries or disruptive artifacts. Validation using synthetic Bishop complex magnetic and gravity datasets, alongside Tuangiao aeromagnetic data from Vietnam, substantiates the robustness and applicability of our modified approach. Furthermore, recognizing the inherent susceptibility of edge detection filters to noise contamination resulting from directional derivatives, we employ the recently developed modified non-local means (MNLM) algorithm to alleviate noise effects prior to the analysis of noisy synthetic and real datasets. Our findings confirm the efficacy of the proposed method in reducing false artifacts and identifying edges with heightened precision, positioning MHGA as a valuable alternative for processing potential field data.

Three‐Dimensional Density Distribution and Seismic Activity along the Guxiang–Tongmai Segment of the Jiali Fault, Tibet

AbstractThe Guxiang–Tongmai segment of the Jiali fault is situated northeast of the Namche Barwa Syntaxis in northeastern Tibet. It is one of the most active strike‐slip faults near the syntaxis and plays a pivotal role in the examination of seismic activity within the eastern Himalayan Syntaxis. New study in the research region has yielded a 1:200000 gravity dataset covering an area 1500 km2. Using wavelet transform multiscale decomposition, scratch analysis techniques, and 3D gravity inversion methods, gravity anomalies, fault distributions, and density structures were determined across various scales. Through the integration of our new gravity data with other geophysical and geological information, our findings demonstrate substantial variations in the overall crustal density within the region, with the fault distribution closely linked to these density fluctuations. Disparities in stratigraphic density are important causes of variations in the capacity of geological formations to endure regional tectonic stress. Earthquakes are predominantly concentrated within the density transition zone and are primarily situated in regions of elevated density. The hanging wall stress within the Guxiang–Tongmai segment of the Jiali fault exhibits a notable concentration, marked by pronounced anisotropy, and is positioned within the density differential zone, which is prone to earthquakes.

Evaluating the Impact of the Recent Combined and Satellite-Only Global Geopotential Model on the Gravimetric Geoid Model

Geoid represents Earth’s surface, ocean, and gravitational field, which influence the elevations, shape, and mass distribution of the geopotential surface, a hypothetical surface that is perpendicular to the direction of gravity at every point. This geopotential surface serves as a reference for measuring elevations and is used as a fundamental reference surface for geodetic and surveying purposes. In this study, the Least Squares Modification of Stokes Formula (LSMS) with Additive Corrections (AC), also known as the KTH method, is used to generate a new gravimetric geoid model for Peninsular Malaysia. The KTH method was developed at the Royal Institute of Technology (KTH) in Stockholm-Sweden. The dataset used is the most recent global digital elevation model, Shuttle Radar Topography Mission (SRTM) 1 Arc-Second Global, generated by the National Aeronautics and Space Administration (NASA) and the National Imagery and Mapping Agency (NIMA). In addition to this elevation data, the dataset includes the Global Geopotential Model (GGM), which is composed of the XGM2016, XGM2019e, Tongji_GGMG2021S, and Tongji-Grace02k models. Furthermore, it incorporates sets of regional gravity data, including terrestrial gravity, airborne gravity, and marine gravity anomalies, all of which are derived from the Technical University of Denmark (DTU 21). The actual 45 Global Navigation Satellite System (GNSS)-levelling points data have been compared to the gravimetric geoid model developed in this study and the geoid acquired from Department of Survey and Mapping Malaysia (DSMM). According to the statistical results, NXGM2019e provides better accuracy, with the Root Mean Square Error (RMSE) geoid model errors of ±0.033 m, compared to the deviations in free-air anomalies, XGM2019e, which has the minimum RMSE of 10.291 mGal. Meanwhile, Tongji-GMMG2021S has the maximum RMSE of 14.792 mGal. The geoid is derived from the XGM2019e model and has maximum and minimum values of 0.032 m and 0.147 m, respectively, with mean residuals of 0.089 m. In conclusion, the XGM2019e has the potential to determine a precise local geoid model for Peninsular Malaysia

Refinement of microplate boundaries assisted by integrated gravity analysis: Application to the Caribbean Sea

Under the long-term influence of subduction, collision and strike-slip faults, the Caribbean Sea and its surroundings have evolved complex topography and terranes, making it an excellent site to study the tectonic of microplates. However, some microplate boundaries of this area are still controversial or unclear. Here we employed the widely-used satellite-derived gravity dataset in combination with previous findings to conduct a detailed re-interpretation of tectonic boundaries. A newly proposed product of normalized multi-edge-attributes (PNMEA) with upward-continued free-air gravity anomalies (FGA) is used to constrain deep large-scale boundaries (i.e., oceanic trenches, deformed belts and fault systems). The residual crustal gravity anomalies (RCGA) obtained based on wavelet multi-scale decomposition further reveal density variations within the crust domain. The Tilt angle (TA) of FGA highlights fault strikes and patterns in the near-surface. Consequently, we refine the possible boundaries of microplates within the northern Caribbean boundary zone and the Nicaraguan Rise, and analyze the contact relationships among microplates. The results suggest a triple junction among the Gonave, Hispaniola and Septentrional microplates exists in the Windward Passage, and a zigzag low RCGA in the Mona Passage separates the Hispaniola and Puerto Rico microplates. In addition, the north and south Nicaraguan rises are inclined to be unaffiliated implied by the differences in multiple physical properties. We thus conclude that an integrated analytical approach involving potential-field edge detection and RCGA can provide additional constraints for identification of tectonic or microplate boundaries. Deep-shallow coupling and lithosphere-scale cooling differences may provide new perspectives to explain the complexity of temporal-spatial configuration due to multiple microplate interactions.

High-resolution regional gravity field modeling in data-challenging regions for the realization of geopotential-based height systems

Modern height systems are based on the combination of satellite positioning and gravity field models of high resolution. However, in many regions, especially developing or newly industrializing countries, there is no (reliable) regional gravity model at all, due to challenges such as limited data availability, unknown/low data quality, and missing metadata. This paper addresses this issue in a case study of Colombia, where eight decades of historical terrestrial and airborne gravity measurements are available but widely contain systematic errors, outliers, and biases. Correspondingly, processing strategies and structures are proposed and applied to validate and improve the quality of old gravity datasets. A novel method is developed based on spherical radial basis functions (SRBFs) for estimating biases, which are found in different airborne surveys with values exceeding 40 mGal. The validity of this bias estimation method is demonstrated both by a simulation test and by the evaluation of the airborne data in comparison to the SATOP (SAtellite-TOPography) model, which merges the satellite-only global gravity model GOCO06s with the Earth2014 topography model. The terrestrial and airborne data are then combined with a global gravity model (GGM), ultra-high-resolution topography models, as well as altimetry-derived gravity anomalies from DTU21GRA for the offshore areas. The results are presented in terms of height anomalies (QGeoidCOL2023), and they are thoroughly validated using GPS/leveling data both in the absolute and relative manner. The standard deviation in comparison to the GPS/leveling data after applying a correction surface to account for the datum inconsistencies amounts to 15.76 cm, which is 27% smaller compared to the mean standard deviation value given by five recent high-resolution GGMs, and 36% smaller than the one delivered by the latest South American quasi-geoid model QGEOID2021. The relative validation results show that QGeoidCOL2023 performs better, i.e., delivers lower RMS errors than the GGMs and QGEOID2021 in all the baseline length groups. These results indicate the validity and benefits of the developed methods and procedures, which can be used for other data-challenging areas to facilitate the realization of geopotential-based height systems.Graphical

New insights into crustal and geological structures beneath the Southern Benue trough of Nigeria and parts of Cameroon Volcanic Line from tailored gravity data

We utilized a high-resolution tailored gravity dataset to investigate the geological structure beneath the Southern Benue Trough of Nigeria and along the Cameroon Volcanic Line (CVL). The tailored gravity data was obtained by applying a stochastic combination technique to integrate global gravity field model, terrestrial gravity data, and residual gravity data over the study area. We then carried out gravity techniques to compile the Bouguer gravity map and to estimate the crustal thickness. To obtain suitable estimates of the reference depth and density contrast of the Moho interface, we fitted the gravimetrically determined Moho geometry to the seismic estimates by minimizing the Root-Mean-Square of their differences. A minimum RMS of 3.6 km at a reference depth of 26 km and a density contrast of 450 kgm−3 was achieved over the study area. Our results reveal a dense magmatic feature criss-crossing the central portion of the study area. This phenomenon led to a thinning of the crust and formation of various geological structures, mainly at the southern end. We could see a very thick sedimentary cover within some of these structures possibly occasioned by compressional and extensional tectonic forces acting at the southwest end. Our study reveals that these compacted sedimentary covers could be important habitats for mineralization. We have also been able to refine and depict the lateral extent of the crustal architecture at a fine scale using our tailored gravity dataset. We concluded that the tectonic events beneath the study area are complex and point to several geophysical factors earlier revealed in published studies. However, a narrowing of two or more conjugate plates (margins) propelled by an upward force may have primarily led to the upward displacement of some of the magmas in-between those plates forming the intrusive rocks.

Structural gravity and the gains from trade under imperfect competition: Quantifying the effects of the European Single Market

The structural gravity model is the workhorse model in international trade to estimate the drivers of trade costs. We propose a new gravity estimation procedure that allows us to disentangle exogenous trade costs and endogenous aggregate markups under oligopoly. Our method can be easily implemented in standard gravity data sets, and we illustrate it by analyzing the competition and welfare effects of the European Single Market. We find that abolishing the European Single Market would increase domestic aggregate markups in EU member countries by 2 to 6 percent. Welfare effects of trade liberalization are larger due to changes in competition among domestic and foreign firms. Our findings highlight that evaluations of trade policy changes and trade cost reductions should also consider their effects on competition.

Rectangular harmonic analysis for gravity field representation by fusing ground gravity and airborne gravity gradient tensor data: A case study in Vinton salt dome, USA

Gravity and Gravity Gradient Tensor (GGT) surveys are commonly used to investigate mineral deposits, oil and gas reservoirs, etc. However, the different kinds of discrete observations with unknown noises are usually irregularly and unevenly spaced. Therefore, the practical observations need to be self-consistently and reliably fused and then the regularly distributed grid data of desired physical quantity can be predicted by the data fusion method. Rectangular Harmonic Analysis (RHA) is one of efficient and easy-to-implement methods for data processing, gravity field representation and so on. Combining ground gravity and airborne GGT data to determine RHA coefficients is beneficial for improving the reliability of complete wavelength components of the gravity field. In this study, we employ the modified RHA method to recover the gravity field by fusing ground gravity and airborne GGT data sets. Through a series of tests with synthetic data, we discuss the option of maximum RHA order, data sampling spaces and performances by using different simulated data sets assemble to represent the gravity field under different practical conditions. The synthetic tests show that the RHA can effectively extract the coherent signals as far as possible from the different data sets and guarantees better fitness between the predicted gravity and GGT data to observed data. Finally, we apply the RHA method to practical ground gravity and airborne GGT data sets over the Vinton salt dome, Louisiana, USA, to represent and predict the gravity and GGT data sets at different altitudes over the study region. As an example of geological application, the predicted GGT data sets are employed to interpret the lithological boundaries with density contrasts beneath the study area.

Spatiotemporal gravity changes at the Santorini Volcanic complex and their interpretation

Understanding the complex dynamics of volcanic systems demands a multidimensional approach that combines geophysics, geology, and geodetics. In this study, we examine observed spatiotemporal gravity changes within the Santorini volcanic complex from 1975 to 2014. The historical data indicates that gravity has been increasing continuously since at least 1966 until our latest measurements in 2014, albeit with a decreasing rate of increase over time. Utilizing gravity inversion of various gravity datasets and evidence from other studies, we explore different scenarios to shed light on the underlying processes. Our preferred interpretation involves both a magmatic episode and continuous evolution of the shallow structure. We find that the 2011-12 unrest period resulted from the intrusion of ∼3.3x1011 kg of basaltic magma at 3 km depth near the previously identified Mogi source. We attribute the continuous gravity increase beneath Nea Kameni to a density increases at about 1350 m depth. We infer these are a result of hydrothermal fluctuations, degassing, and/or vesicle collapse within the stored magma. Units1mGal = 10-5 m/s2 (SI)

Modified non-local means: A novel denoising approach to process gravity field data

Abstract Gravity measurement is a basic geophysical method for non-destructive exploration of mineral resources and hydrocarbons and also for geological studies. The quality of gravity data measured is constantly degraded by a low signal-to-noise ratio. Noise attenuation thus plays a vital role in processing and interpreting gravity field data. The non-local means (NLM) filtering was first and successfully introduced to attenuate randomly distributed noise situated in seismic records in geophysical community. However, less attention has been drawn to apply NLM to denoise potential field data, since the success of NLM is guaranteed by carefully tuned parameters and large computational costs. Here we propose the modified NLM (MNLM), based on unweighted Euclidean distance and integral image method, to denoise gravity datasets. The unweighted Euclidean distance is used to reduce the uncertainty and complexity of tuning the control parameters involved, and the integral image strategy is applied to avoid the enormous computational cost of the NLM. Since these filtering properties are desirable to mitigate noise in gravity datasets, we test and evaluate the MNLM filter on noisy synthetic gravity models with uniform and normal distributions and on real data from the Mariana trench and Slovakia, and compare it to other standard and representative denoising filters. The results on synthetic and field datasets confirm the high speed of this modified algorithm and show that, it removes noise most effectively while clearly preserving and not blurring structural details with less tuned parameters. The MNLM filter can therefore be considered as a promising and novel algorithm for denoising gravity data.

Zones of Weakness Within the Juan de Fuca Plate Mapped From the Integration of Multiple Geophysical Data and Their Relation to Observed Seismicity

AbstractThis study aims to explain the nonuniform earthquake pattern along the Cascadia Subduction Zone. In particular, we investigate the relationship between the tectonic features of the subducting oceanic Juan de Fuca slab and the onshore seismicity pattern. We have integrated multiple geophysical data sets toward three general objectives. The first study intends to study variations in physical properties along three 2‐dimensional models through regions of different seismicities that combine public gravity, magnetic, and seismic data sets. These models reveal multiple zones of decreased crustal density that we interpret as regions of weaker oceanic crust. The second objective is to delineate major tectonic features by performing spatial analysis of potential fields. The overall methodology comprises gravity and magnetic data filtering, followed by lineaments mapping and cross‐referencing interpretation with available seismic reflection data. This process allows delineating zones of crustal weakness by extrapolating outside our three 2‐D models. We also map multiple seamounts that appear to cluster along identified zones of weaker crust. Third, we investigate the relationship between the mapped tectonic elements, namely the zones of weak crust with accompanying seamounts, and the observed seismicity trends within the subducted slab. The alignment between those suggests that mapped weak crust zones and associated seamounts may have an influence on the overall subduction process. As more of these structures are heading toward the Washington portion of the margin than to the Oregon portion, more earthquakes are observed in the north than in the south.

Space based Earth observation approach for exploring hydrocarbon prospects in an intracratonic rift basin – A study in north Cambay basin, Gujarat

In the present study, we carried out a conjugate analysis of Landsat-8 Operational Land Imager (OLI), Sentinel-2B Multi-Spectral Instrument (MSI), Advanced Land Observation Satellite Phased Array L-band SAR (ALOS PALSAR), and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data over a study area of northern Cambay Basin to delineate prospective areas for hydrocarbon exploration. In this regard, we utilized feature-oriented principal component (PC) images of Landsat OLI data, PC images of Sentinel-2B visible and near-infrared (VNIR)-short-wave infrared (SWIR) bands, thresholded Cartosat-1 Digital Elevation Model (DEM), and polarization image composite of ALOS PALSAR data to delineate geomorphic and lineament features in the study area. Most of the geomorphic features, such as scroll plain, gullies, elevated pediment, circular drainage anomalies, etc., indicate localized structural uplift. Geomorphic anomalies and lineaments, essential for identifying structural controls of near-surface hydrocarbon accumulation, were identified using enhanced satellite data. Geophysical anomalies derived from gravity datasets supplemented the presence and down-depth continuity of geological structures. Spectral profiles of calcrete-bearing soil samples were used to identify calcrete-rich zones in the optical remote sensing image data as a proxy owing to field evidence of close association of calcrete-rich soils with known subsurface hydrocarbon accumulations. Sub-pixel mapping algorithm Constrained Energy Minimization (CEM) applied to SWIR bands of ASTER data was used to delineate surface proxies of near-surface hydrocarbon seepage. Isopach maps of shallowest reservoir formations (Mid-/ Late Eocene) were used as indicators of favorable near-surface hydrocarbon accumulation.Earth observation-based geomorphic, lineament, and spectral anomalies were integrated with supplementary datasets, such as reservoir isopach and absorbed gas anomalies, as controls using the weighted summation method for quantitative deduction of the hydrocarbon potential map of the study area. The weights for input variables or parameters (geomorphic, spectral, geochemical, etc.) were inferred based on spatial associations of these anomalous units/variables with the existing oil & gas well locations. The identified potential map is in broad synergy with the field observations on localized uplift, geo-botanical anomalies, and calcrete-rich zones within the extent of high & moderate hydrocarbon potential areas.

Permo-Triassic cyclicity on the western shoulder of Muzaffarabad-Hazara paleo-high, during the oceanisation of Neo-Tethys

The sedimentary record of Permo-Triassic (299 Ma to 201 Ma) is only found on the periphery of the Hazara-Kashmir Syntaxis (HKS), i.e., on the western (central Potwar Sub-basin and its west) and eastern (Zanskar-Spiti Basin) shoulders. During this period, HKS acted as an indentation named as Muzaffarabad-Hazara Paleo-high (MPH), where no sedimentation occurred. Previously, the existence of MHP remained questionable as it has yet to be defined with the help of an integrated sequence stratigraphic model built by using outcrop, petrography, drilled well, regional correlations, seismic and gravity data sets on its western shoulder.Permo-Triassic strata outcrop in the western Salt Range, where stratigraphic surfaces, stratal terminations, and their bounding sequences are designed. Permo-Triassic is a mega sequence comprising of two sequences (Permian and Triassic) bounded by SUs. Non-marine (fluvial) Warchha Sandstone split the Permian sequence into two sub-sequences (siliciclastic/clastic and carbonate sequences). The Triassic sequence has the same depositional architectural features have two sub-sequences. Flooding events (i.e., four MRS/MFSs) influenced every sub-sequence, which developed retrogradational and progradational cyclicity during this period. The defined cyclicity, stratigraphic surfaces, and stratal terminations are validated with the well-log motif cycles and seismic data.Composite unconformities developed towards the MHP; therefore, only flooding events are correlatable on both shoulders. During the Sakmarian (290 Ma) age, a flooding event with maximum accommodation space (15–20 m) deposited the middle shelf facies (Amb Formation), which is correlatable with carbonates of Panjal volcanics and transgressive Gechang Formation of Zanskar-Spiti Basin. The third flooding event of the Ceratite Bed of Lower Triassic is also correlatable. Flooding continued in Zanskar-Spiti Basin in Middle Triassic, but diastem was observed in the western Salt Range. Carbonates younger than Ladinian (242-237 Ma) age are only found in Zanskar-Spiti Basin, but during this phase, SU truncated the Triassic strata in the Salt Range.

Fault Delineation and Geological Carbon Storage (GCS) Characterization for the CCS and CCUS Facilities Based On Gravity Dataset. A Case Study in the Northern Part of East Java, Indonesia

lobal warming, the impact of greenhouse-gases emission has triggered climate change and caused various geological and hydro-meteorological disasters in the world. Most countries have carried out decarbonization efforts following the Paris Agreement, which aims to reduce carbon emissions from 29% of domestic effort up to 41% with international support by 2030. Sustainable Development Goal number 13 states combating climate change is a globally accepted framework adopted by the Indonesian Ministry of Development Planning. One aspect of decarbonization efforts involves establishing successful CCS/CCUS facilities, which requires readiness of geological carbon storage (GCS). The GCS has limited capacity, locate specifically underneath, and must consider nearby faulting system to avoid leakage and uncontrollable behavior after the injection phase of the liquefied (high-pressure) carbon. This study optimizes gravity dataset analysis to identify the existing faults and characterize the initial stage of proposed GCS in the northern part of East Java, Indonesia. Synthetic modeling of a strike slip fault was conducted to support data interpretation. The GCS characterizations, which include shape, depth, and storage capacity estimations, are inferred through 3D gravity inverse modeling. This study deduced the presence of a large-scale anticline closure without any intersecting of strike-slip fault in the area. The existing fault system is identified as the Baribis-Kendeng Reverse Fault Zone, trending west-east, and intersected by a sinistral strike-slip fault in the northeast-southwest direction. The study area is suggested as a potential GCS location with low-risk of leakage, located adjacent to the Central Processing Plant Gundih and Sukowati in East Java, Indonesia

Gravity corrections for the updated italian levelling network

The Italian official height system is defined through a high precision levelling network established and maintained by the Istituto Geografico Militare - IGM. During the last 20 years, IGM has performed levelling campaigns on almost the whole peninsular area of Italy with the aim of both densifying the existing network and updating the reference heights. This paper reports about the procedure applied to correct the levelling observations for the gravity effects and the assessment on the results. The needed gravity values were predicted from the Italian gravity dataset (IGD), and both from EGM2008 and XGM2019e high resolution global gravity models. A new formulation of the normal correction as well as the standard orthometric correction were applied. The IGD derived corrections proved to be effective by reducing the misclosure error of critical loops below the tolerance level. Gravity data derived from EGM2008 and XGM2019e proved to be too poor for the correction purposes, as it was also confirmed by a comparison against available observed data, with RMS of the differences, in Alpine ares, ranging between 50 and 100 mGal.