Orals: Tue, 5 May, 08:30–10:15 | Room -2.20
In airborne vector gravimetry algorithms based on SINS/GNSS integrated navigation, the ultimate accuracy of horizontal attitude resolution is primarily constrained by the combined effects of horizontal gravity disturbances and accelerometer measurement errors. Gravity disturbances along the survey line enter the error propagation equations of the strapdown inertial navigation system (SINS) via the sensitivity of accelerometers, forming a closed-loop coupled error propagation chain related to horizontal gravity disturbances. This increases the difficulty of error processing and gravity vector determination. To address this issue, this paper proposes an airborne vector gravimetry method based on independent gyroscopic observation. The method introduces an independent gyros-based attitude determination approach into the traditional SINS/GNSS integrated navigation algorithm. It utilizes the gyroscope assembly of the SINS to independently update the attitude in the inertial frame. The geographic position and time information from GNSS are then used to transform this inertial-frame attitude to the navigation frame for use. A key feature of this method is that it does not employ accelerometer measurements during the attitude update process, thereby avoiding the influence of accelerometer errors and gravity disturbances on the horizontal attitude and achieving decoupling of the closed-loop error propagation chain. Building upon this foundation, the study investigates the linear mapping relationship between the horizontal attitude errors independently resolved by the gyroscope and the horizontal gravity disturbances. Error compensation for airborne gravity vector measurements is performed using gravity anomaly information derived from the EGM2008 model, with both simulated and field data employed for validation. The airborne gravity survey experiments demonstrate that the internal consistency accuracies for the eastward, northward, and upward gravity anomaly components are 1.53 mGal, 2.34 mGal, and 0.59 mGal, respectively, with a spatial resolution of approximately 3 km. This method significantly enhances the decoupling capability between accelerometer measurement errors and gravity disturbances, thereby improving the measurement accuracy of horizontal gravity components.
How to cite: Xiang, W., Cai, S., Guo, Y., Cao, J., Xiong, Z., Luo, K., Yu, R., and Wu, M.: Airborne Vector Gravimetry Method Based on Independent Gyros Observations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15624, https://doi.org/10.5194/egusphere-egu26-15624, 2026.
Gravity-matching navigation—a self-contained and passive navigation modality—depends critically on the accuracy and resolution of the background gravity field and the adaptability of the matching algorithm，Current gravity modeling methods, however, are limited by slow model updates and inefficient storage under dynamic operating conditions. To overcome these challenges, we introduce a novel gravity-matching framework that integrates incremental learning with adaptive mesh optimization.
Our approach proceeds in three key stages. First, a global gravity field is rapidly initialized using a spherical-harmonics model trained via an Extreme Learning Machine (ELM). We then employ an online sequential ELM (OS-ELM) to incrementally assimilate posterior gravity information—whether obtained in real time or fused from multi-source observations—thereby enabling timely model updates and continuous refinement of field fidelity.
Second, we systematically evaluate the sensitivity of batch-matching algorithms (e.g., ICCP and contour matching) to interpolation density and derive an adaptive density-selection criterion that incorporates prior map information content, vehicle velocity, and inertial navigation system error growth. To improve storage and computational efficiency, we replace conventional rectilinear grids with a hexagonal tessellation for field discretization. Theoretical analysis and experimental results confirm that, at equal nominal resolution, the hexagonal lattice reduces both model and localization errors while its structural isotropy enhances the stability and convergence of batch matching across diverse heading angles.
Third, we introduce an encrypted interpolation strategy centered on hexagonal cell centroids. This approach increases effective resolution with only a minor increase in storage, thereby improving the algorithm’s ability to resolve subtle gravity features. Numerical simulations and field data demonstrate that the proposed framework sustains high-precision matching performance while significantly reducing storage and computational burdens, offering a promising technical pathway toward long-endurance, robust gravity-matching navigation in complex environments.
How to cite: Zhao, R., Yu, R., Luo, K., Xiong, Z., Cao, J., Cai, S., Guo, Y., and Wu, M.: Hex-OSGM: Incremental Gravity Field Learning on Adaptive Hexagonal Meshes for Robust Passive Navigation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15998, https://doi.org/10.5194/egusphere-egu26-15998, 2026.
Gravity surveys are well known for the exploration of frontier basins and understanding of the crustal structures. Recent advances in gravity instrumentation along with processing and interpretation techniques have significantly improved the accuracy of the gravity surveys. The increased accuracy of the gravity measurements has led to Time Lapse gravity (also known as 4D gravity) monitoring of the Oil/Gas fields, where repeatability of the various gravity surveys at different time intervals are crucial.
Plan is to showcase two examples, one related optimum gridding of land 2-D gravity survey based on the scaling concept from Vindhayan basin of India and another where gravity is efficiently used in a very cost effective way for the field management based on repeated gravity measurements at seafloor (Time Lapse gravity) for subsidence and fluid movement monitoring in North sea.
How to cite: Dimri, V. P. and Srivastava, R. P.: Gravity from exploration to field management, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1487, https://doi.org/10.5194/egusphere-egu26-1487, 2026.
High resolution magnetic surveys of the seafloor have become more ubiquitous in recent times with the broad application of autonomous underwater vehicles (AUV) to seafloor investigation. AUVs can follow a precise path repeatedly which allows to the possibility of repeated measurements through time. This provides unique insight in what was considered mostly static seafloor magnetic properties. Some examples of dynamic magnetic field include anomalies associated with recent lavas cooling and becoming magnetized, while deep-seated thermal anomalies associated with magma chambers may demagnetize the overlying crust and create a detectable signal at the seafloor if not the sea surface. We present an update to a temporal magnetic study of Axial seamount in the northeast pacific. Axial Seamount is active having erupted in 2015, 2011, and 1998. Axial is part of the Ocean Observatory Initiative Regional Cabled Array. Magnetic field is not monitored but repeat, semi-yearly surveys have been done by AUV Sentry for geodetic purposes which happily also collects magnetic field data. We present recent 2024 results from Axial Seamount as it inflates for a future eruption.
How to cite: Tivey, M.: Temporal Magnetic Surveys using Autonomous Underwater Vehicles, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3598, https://doi.org/10.5194/egusphere-egu26-3598, 2026.
Geothermal energy is an essential renewable resource whose effective development relies on subsurface structure, particularly in regions with high geothermal potential. Magnetic surveying serves as a fundamental geophysical tool in this context, enabling the identification of concealed intrusions, estimation of source depths, and delineation of buried dykes or faults. While regional airborne campaigns offer efficient coverage, their resolution is often limited by wide survey-line spacing and high flight altitudes. Conversely, ground-based surveys, though detailed, are frequently hindered by rugged terrain and accessibility issues. Drone-borne aeromagnetic surveys address these limitations, providing high-resolution datasets in areas with complex topography.
In this study, we utilized a total-field scalar magnetometer integrated with a multicopter Unmanned Aerial System (UAS) to acquire magnetic measurements. The UAS followed pre-programmed survey lines defined by GPS waypoints and employed terrain-following flight modes at constant altitudes no higher than 120 m above ground level, which are substantially lower than those of conventional airborne surveys and allow measurements to be acquired closer to subsurface magnetic sources. Surveys were conducted at multiple altitudes to calculate vertical magnetic gradients, which serve as essential constraints for modeling subsurface magnetic susceptibility distributions. The data processing workflow comprised spike removal, International Geomagnetic Reference Field (IGRF) correction, and diurnal correction. The processed data were subsequently gridded using the natural neighbor interpolation method to generate magnetic anomaly maps.
Our drone-borne aeromagnetic surveys in volcanic regions have demonstrated strong consistency with existing aeromagnetic datasets while offering significantly enhanced spatial density. This study extends the application of drone-borne aeromagnetic surveying to a metamorphic formation with lava flows. Distinct magnetic anomaly patterns are observed at different flight altitudes. Ongoing research involves the application of computational methods and modeling to analyze these altitude-dependent phenomena and refine the interpretation of subsurface magnetic source distributions.
How to cite: Chang, C.-W., Huang, W.-J., Chen, C.-C., and Kao, J.-Y.: Validation of Drone-Borne Aeromagnetic Surveys Using Multi-Altitude Measurements in Rugged Terrains, Taiwan, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12493, https://doi.org/10.5194/egusphere-egu26-12493, 2026.
This study presents a fully automatic inversion technique for interpreting magnetic anomalies of two-dimensional (2D) listric fault structures with arbitrary magnetisation. Listric faults exhibit curved geometries with steep dips near the surface that decrease with depth. But most studies assume a planar fault geometry to the listric faults, which is rarely valid in reality. Accurately modelling such structures is essential because many sedimentary basins and extensional tectonic settings contain listric faults that significantly influence subsurface geometry. Forward modelling is performed using the equation derived by Ani Nibisha et al. (2021), that computes magnetic anomalies of listric faults in any component (vertical, horizontal, or total), with arbitrary magnetisation directions by incorporating both induced and remanent magnetic components. In the proposed method, polynomial function of arbitrary degree is used to represent the nonplanar fault surface. The coefficients of these polynomials, with structural parameters like depths to the top and bottom of the fault, location of the fault edge, and magnetisation intensity and direction, are estimated directly from the magnetic anomaly profile. The inversion uses Marquardt’s (1970) algorithm for optimisation. With a vertical step approximation, the initial parameters are generated automatically based on certain characteristic anomaly features like maximum and minimum anomaly points, and are updated iteratively until a predefined convergence criterion is satisfied. The misfit between observed and calculated anomalies guides model updates, and the method adaptively adjusts the damping factor to ensure stable convergence. The validity and robustness of the inversion technique are demonstrated through two examples. In the synthetic test, a fifth-degree polynomial is used to describe the fault geometry, and Gaussian noise is added to the computed anomalies for a realistic approach. The inversion successfully reconstructs the geometry, magnetisation intensity, and direction, even when lower-order polynomials (second or third degree) are used, since the optimal degree to define the fault geometry remains unknown with the absence of apriori information about the subsurface during inversion. This demonstrates that the technique can produce geologically reasonable solutions even without precise prior knowledge of the fault’s curvature. This technique is compared with the inversion technique by Murthy et al. (2001), which assumes planar fault surfaces and shows that such simplified models fail to recover realistic structures for listric faults. The method is further applied to real total-field magnetic anomalies from the western margin of the Perth Basin, Australia, which is known for hydrocarbon prospectivity and characterised by deep, curved normal faults. Using a second-degree polynomial, the technique identifies a listric fault with its top near 4 km depth and bottom near 14.8 km, yielding a close fit to observed anomalies with small residuals. The recovered geometry aligns well with seismic observations that reveals the listric nature of the fault (Middleton et al. 1993), reinforcing the reliability of the inversion approach. In contrast, inversion assuming a planar fault plane produces geologically inconsistent results. In conclusion, this technique improves the interpretation of magnetic datasets in regions dominated by extensional tectonics and curved fault structures, offering more realistic subsurface models than traditional planar-fault methods.
How to cite: Nibisha, A. and Vishnubhotla, C.: Interpretation of Magnetic Anomalies of 2D Listric Faults with arbitrary magnetisation: A Polynomial-Based Automatic Inversion Approach, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1015, https://doi.org/10.5194/egusphere-egu26-1015, 2026.
The Assarag region is located in the northern part of the Ouzellagh-Siroua salient, being a segment of the central
Anti-Atlas basement bulging within the High-Atlas Belt of Morocco. It consists mainly of the Late Ediacaran
Magmatic Suites (LEMS) of the Ouarzazate Group (580-539 Ma). The LEMS comprise high potassic calc-alkalic I type
granitoids that host the Imourkhssen Cu-Mo-Au-Ag porphyry mineralization. The aeromagnetic data from
the Assarag region led to describe structural features in the LEMS based on their magnetic footprints. aeromagnetic
datasets were processed using several transformations including the reduction to pole (RTP), Upward
continuation (UC), Tilt derivative (TD), Center for Exploration Targeting (CET) and Euler deconvolution (ED)
filters. RTP, TD and CET transformations allowed to map NNE-SSW, NNW-SSE and NE-SW trending faults in the
north, in addition to a curved magnetic halo in the southwestern part of the Assarag area. The UC filter subdivided
the Assarag area into two magnetic morpho-structural domains: a northern region with low-magnetic
features, and a southern high-magnetic region with positive curved trending patterns. The ED results match
and support the extracted lineaments. The aeromagnetic data were also processed by a 2D Spatio-Spectral
Feature Extraction and Selection tool (SFES2D) using two-dimensional continuous wavelet transformations
(2D CWT), principal component analysis (PCA) and independent component analysis by kurtosis and negentropy
methods (k-ICA and n-ICA). The PCA results corroborate previously extracted lineaments and highlight a new
ENE-WSW oriented structure. Meanwhile, the CWT allowed us to conclude that NNE, NNW and NE trends are
shallow and emphasized deep NW-SE and ENE-WSW structures in the southern part of the Assarag area. ICA
emphasizes the ENE lineament and matches the previous results. We herein define the deeper ENE trend as a part
of the South Atlas Fault (SAF), which crosscuts the LEMS in the study area. Meanwhile, the shallow NE-SW and
NNE-SSW tectonic features likely served as conduits for the ore-bearing fluids, leading to the Imourkhssen Cu-
Mo-Au-Ag mineralization. Consequently, these directions present a valuable approach for guiding mineral
exploration in the Ouzellagh-Siroua salient, from prospect to regional scales.
How to cite: Ferraq, M., Belkacim, S., Cheng, L.-Z., and Abbassi, B.: Aeromagnetic data from the Assarag area (Ouzellagh-Siroua salient, central Anti-Atlas, Morocco): Implications for the Imourkhssen porphyry mineralization, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-450, https://doi.org/10.5194/egusphere-egu26-450, 2026.
Here we present a multidisciplinary, high-resolution investigation of Healy submarine volcano, located in the southern Kermadec arc, New Zealand, combining magnetic, sidescan, and hydrothermal plume datasets to constrain the structure and evolution of its magmatic–hydrothermal system.
Near-seafloor magnetic and sidescan sonar data acquired by the Autonomous Underwater Vehicle (AUV) Sentry have been integrated with shipborne magnetic and gravity measurements, multibeam bathymetry, acoustic backscatter, and hydrothermal plume observations, as well as seafloor imagery and in situ temperature measurements collected by the Pisces V submersible, to develop a detailed geological and geophysical characterization of the volcano.
High-resolution sidescan sonar data reveal fine-scale volcanic and tectonic structures, including lava flow textures, fracture networks, and cone morphology providing context for interpreting magnetic anomalies and hydrothermal plume results. Magnetic ‘lows’ are spatially associated with older, caldera-related structures and demarcate zones of ancient hydrothermal discharge, consistent with the loss of magnetite due to hydrothermal alteration. By contrast, younger basaltic cones emplaced along NNE–SSW-trending lineaments exhibit relatively high magnetization signatures and host the currently active hydrothermal venting, characterized by directly observed low-temperature discharge, while hydrothermal plume data (e.g. turbidity anomalies) suggest the possible presence of higher-temperature venting. Taken together, the spatial distribution of volcanic facies, structural lineaments, magnetization patterns, and hydrothermal activity suggests a temporal evolution in magma emplacement and fluid pathways. This evolution is consistent with a transition from caldera-related, arc-dominated volcanism toward more localized basaltic magmatism exploiting extensional structures, which may reflect the early development of back-arc extension.
Our results highlight the important role of multi-sensor, high-resolution surveys in developing robust conceptual models of submarine volcanic systems, and demonstrate how combined gravity, magnetic, sidescan, and hydrothermal plume investigations are prerequisites for understanding hydrothermal processes and related resources in remote deep-sea environments.
How to cite: Bagnasco, A., Caratori Tontini, F., E. J. de Ronde, C., L. Walker, S., Cocchi, L., Ghirotto, A., and Armadillo, E.: High-resolution magnetic, sidescan, and water column constraints on the tectono-magmatic and hydrothermal evolution of Healy submarine volcano, Kermadec arc, New Zealand, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3376, https://doi.org/10.5194/egusphere-egu26-3376, 2026.
The Wilkes Subglacial Basin (WSB) is one of the largest tectonic features in East Antarctica as it stretches for almost 1600 km from the Southern Ocean towards South Pole. Significant research has focussed on the tectonic origin of the basin with competing models ranging from Paleozoic, Mesozoic and Cenozoic extensional models to flexural models related to the Cenozoic uplift of the Transantarctic Mountains. Comparatively little effort has however been placed on investigating the cryptic basement of the WSB despite its key location at the transition between the exposures of the Archean-Mesoproterozoic Terre Adelie Craton and the late Neoproterozoic to Ordovician age Ross Orogen.
Here we present enhanced aeromagnetic and airborne gravity imaging augmented by satellite magnetic and satellite gravity data and comparisons with formerly adjacent southeastern Australia to redefine key features of the basement in the northern WSB region.
We show that a prominent magnetic low located beneath the Western Basins within the WSB is not caused by a ca 3 km thick Cambrian rift basin as previously proposed (Ferraccioli et al., 2009, Tectonophysics) but images instead a linear Archean crustal ribbon extending further north to exposures of Archean rocks in the Terre Adelie craton and in the Gawler Craton. Cambrian sedimentary basins are confirmed further east beneath the northern Central Basins. Prominent magnetic highs along the eastern flank of the WSB and at the edge of the southern Central Basins were previously interpreted to reveal Ross age igneous basement associated with an arc-back arc system. However, the occurrence of longer wavelength satellite magnetic anomalies both in the WSB and at the edge of the Gawler Craton and in the Curnamona Craton in Australia lead us to propose an alternative hypothesis that predicts the occurrence of more extensive Paleo to Mesoproterozoic basement than previously inferred. Furthermore, a prominent linear residual gravity anomaly along the western flank of the WSB is interpreted here as reflecting uplifted mafic lower crust associated with Paleoproterozoic rifting. High amplitude aeromagnetic anomalies may reflect coeval banded iron formations associated at shallower crustal levels with such Paleoproterozoic rifting processes.
By comparing gravity signatures over the WSB and southern Australia and by incorporating recent seismic constraints at the transition between the Gawler Craton and the Delamerian Orogen we reassess the extent and architecture of both the Precambrian and Cambrian basement.
Overall, our results and models have significant implications for tectonic studies of the basement of the WSB, including better defining the role of inherited tectonics structures on the more recent Paleozoic, Mesozoic to Cenozoic evolution of the WSB. Furthermore, the larger degree of heterogeneity in the crustal basement identified here will help inform next generation models of intracrustal contributions to geothermal heat flow beneath this key sector of the East Antarctic Ice Sheet.
How to cite: Ferraccioli, F., Ooi, S. Q., Al-Badani, M. A., Young, D., Blankenship, D., Armadillo, E., Ebbing, J., and Siegert, M.: Enhanced magnetic and gravity imaging of the crustal basement beneath the northern Wilkes Subglacial Basin in East Antarctica, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21409, https://doi.org/10.5194/egusphere-egu26-21409, 2026.
Continental sutures are fundamental markers of past plate convergence, yet their geological expression varies markedly depending on erosion level and crustal depth. Classical descriptions of sutures emphasize narrow, localized zones characterized by ophiolites, mélanges, arc-related assemblages, and high-pressure metamorphic rocks, often exposed at the surface. However, such features typically reflect shallow-crustal levels of preservation. Here we demonstrate that deeply eroded or buried sutures may lack this diagnostic surface expression and instead form wide, diffuse boundary zones within the middle and lower crust, extending laterally for 100–200 km. This conceptual framework is illustrated with two contrasting examples from Europe: the early Palaeozoic suture between Baltica and Avalonia and the Paleoproterozoic suture between Fennoscandia and Sarmatia within the East European Craton.
The first case examines the German–Polish Caledonides and the Thor Suture separating Avalonia from Baltica. Integration of geological data with reinterpretation of the Basin-9601 deep seismic profile, complemented by newly constructed 2-D forward gravity modelling and regional gravity and magnetic compilations, allows refinement of the crustal architecture across eastern Germany and western Poland. The Caledonian Deformation Front is shown to mark the northern limit of a thin-skinned fold-and-thrust belt, composed of Ordovician metasediments derived from a Caledonian accretionary wedge near Rügen and of deformed foreland-basin sediments incorporated into the orogenic wedge farther east. In contrast, the Thor Suture itself—defined as the thrust of Avalonia’s crystalline basement over Baltica—is located ~120 km farther south, beneath the depocentre of the North German Basin and along the Dolsk Fault Zone in western Poland. At depth, the lower crust of Baltica is underthrust southward to the Flechtingen High and toward the Variscan Rheno–Hercynian suture. This geometry demonstrates that, although the Caledonian suture has a narrow and classical expression in the shallow crust, it broadens downward into a wide lithospheric-scale transition zone, coinciding with mantle lithosphere necking between thick Baltican and thinner Avalonian lithosphere.
The second example addresses the Paleoproterozoic Fennoscandia–Sarmatia Suture (FSS) in eastern Poland. Reassessment of deep reflection seismic data from the PolandSPAN™ survey, combined with 2-D gravity and magnetic modelling and 3-D models of basement depth and crustal thickness, reveals a fundamentally different suture style. Rather than a discrete fault, the FSS is expressed as a 100–120 km wide transitional zone involving the Belarus–Podlasie Granulite Belt and the Okolovo Belt. These domains are characterized by anomalously dense and magnetically susceptible lithologies, interpreted as remnants of arc-related magmatic complexes, mafic igneous suites, and high-pressure metamorphic rocks. Seismic and potential-field data demonstrate that these features continue through the entire crust, indicating a deeply rooted Paleoproterozoic collision that has been subsequently overprinted but not obliterated.
Together, these examples show that sutures preserved at shallow levels are narrow and lithologically distinctive, whereas deeply eroded or ancient sutures are cryptic, broad, and best recognized through integrated seismic and potential-field analyses. At the same time, we acknowledge that differences in Precambrian versus Phanerozoic tectonic regimes—such as lithospheric strength, thermal structure, and strain distribution—may further contribute to the development of especially wide deformation zones in Palaeoproterozoic sutures.
How to cite: Mikołajczak, M., Mazur, S., Stephenson, R., Schiffer, C., Krzywiec, P., and Majka, J.: From Sharp to Diffuse: How Erosion Level Controls the Architecture of Continental Sutures in the Crust, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11430, https://doi.org/10.5194/egusphere-egu26-11430, 2026.
Posters on site: Wed, 6 May, 08:30–10:15 | Hall X2
Gravity is a fundamental geophysical method that provides unique insight into subsurface density variations. Its sensitivity spans an exceptional range of spatial scales, from centimetre-scale laboratory experiments and borehole measurements to continental - and global-scale satellite observations. Despite its long-standing application, the practical limits and resolving power of gravimetry across these scales are still not widely appreciated. At regional to global scales, satellite missions such as GRACE and GOCE have transformed our understanding of mass redistribution within the Earth system. They enable the monitoring of ice mass loss, hydrological change, and large-scale mantle processes, achieving microgal (10⁻⁸ m s⁻²) accuracy with spatial resolutions of several hundred kilometres. These capabilities demonstrate gravimetry’s strength in detecting large-scale density anomalies and temporal mass transport. At crustal and reservoir scales, terrestrial and airborne gravity measurements resolve subtle variations related to geological structures, sedimentary basins, and fluid movements. Advanced data processing- such as terrain, Bouguer, and isostatic corrections- improves signal fidelity, while time-lapse relative gravimetry can detect changes associated with e.g. volcanic unrest, groundwater depletion, and reservoir dynamics down to the sub-microgal level. At the smallest scales, absolute gravimeters and emerging quantum sensors push precision further, enabling laboratory-based density determinations and environmental monitoring with unprecedented stability. Increasing resolution, however, introduces challenges related to topographic effects, instrumental drift, and signal ambiguity, requiring robust modelling and/or inversion strategies, and integration with complementary geophysical data. We review representative applications across satellite, regional, and local domains, quantify achievable spatial and temporal resolution, and discuss future perspectives, joint interpretation with magnetic and seismic methods, and the growing role of artificial intelligence in gravity data analysis.
How to cite: Götze, H.-J. and Anikiev, D.: Gravimetry across spatial scales – how powerful is gravity?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3131, https://doi.org/10.5194/egusphere-egu26-3131, 2026.
Analytic solutions for the gravitational potential of a homogeneous ellipsoid have existed since the first half of the nineteenth century, while analytic solutions for the magnetic field were developed by the end of the same century. The existence of such analytic solutions allowed geophysicists to use ellipsoidal bodies to approximate complex geological structures and model their respective gravity and magnetic fields. Ellipsoids are of particular interest for modelling ore bodies and structures with high magnetic susceptibilities, since they are the only geometric bodies with analytic solutions for their magnetic field that account for self-demagnetization effects. Nonetheless, modern, easy-to-use, up-to-date, and open-source implementations of these analytic solutions are scarce if non-existent.
We present an open-source Python implementation of the analytic solutions of the gravity acceleration and magnetic field generated by homogeneous ellipsoids with arbitrary rotations. This new code allows users to easily define ellipsoids by their semi-axes lengths, the coordinates of their geometric centers, and three rotation angles. The gravity acceleration and magnetic field they generate can be computed on any point in space, including internal and external points to the bodies, through specific functions for each field. The code supports triaxial, prolate and oblate ellipsoids, including spheres. Users can assign physical properties to each ellipsoid, like its mass density, magnetic susceptibility, and remanent magnetization. The magnetic susceptibility can be a single value for isotropic susceptibility, or a second-order tensor to account for anisotropy. The total magnetization of the ellipsoid is obtained as a combination of the induced and remanent magnetization, accounting for self-demagnetization effects.
This implementation can be used to predict the gravity and magnetic field of any set of ellipsoids for hypothesis testing, survey designing, and stochastic inversions. In future work, we plan to include analytic derivatives of the fields with respect to ellipsoid's parameters, so the code can also be used for deterministic inversions.
The ellipsoid class and their forward modelling functions have been included in Harmonica: an open-source Python package for processing and modelling gravity and magnetic data, part of the Fatiando a Terra project. We followed best practices for its development, including thorough testing and extensive documentation, leading to a robust, well-designed, and well-tested implementation of such analytic solutions.
How to cite: Soler, S., Baker, K., and Heagy, L.: Open-source gravity and magnetic forward model of ellipsoids, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8366, https://doi.org/10.5194/egusphere-egu26-8366, 2026.
High-resolution gravity data were used to assess their potential and limitations as a subsurface investigation tool to constrain key geological structures and support georesource exploration in Northwestern Tunisia. In this structurally complex area, methodological choices—particularly those related to regional–residual separation, derivative filtering, interpolation schemes, and Euler-based depth-estimation parameters—significantly influence the geometry, continuity, and uncertainty of interpreted lineaments.
To mitigate these effects, we applied an integrated multi-stage workflow combining residual anomaly mapping, derivative filters, tilt-angle transformation, power-spectrum analysis, Euler deconvolution of horizontal gradients (EHD), and 3D Euler solutions. These complementary approaches delineate subsurface fault systems and highlight deep structural controls on Triassic salt diapirs and associated Pb–Zn mineralization. The results reveal a dominant NE–SW structural corridor with fault depths reaching ~1.75 km, spatially correlating with known mineralized sites and salt-dome boundaries.
To further enhance structural reliability and quantify subsurface density distributions, the workflow incorporates 3D gravity inversion. The inversion model helps image density contrasts associated with the Triassic evaporites, validating interpreted lineaments and refining depth estimates derived from derivative-based and Euler approaches. Integrating forward–inverse modelling with classical interpretation tools not only enhances the structural understanding but also provides a clear workflow, helping users assess the reliability and limitations of gravity-derived structural maps in tectonic complex areas.
How to cite: hamdi, I., Sobh, M., Amiri, A., and Mohamed hédi, I.: A Multi-Method Gravity Workflow for Reliable Structural Mapping in Northern Tunisia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19968, https://doi.org/10.5194/egusphere-egu26-19968, 2026.
This work presents a new method for interpreting potential geomagnetic field data. It combines the analytical signal method, which is independent of the direction of magnetization, with the two-dimensional continuous shearlet transform (CST). First, the dominant directions of the structural geological features of a given area are estimated using geological data and conventional interpretation methods such as horizontal gradient, Euler deconvolution and wavelet transform. These directions are then used to determine the shearing parameters required for the shearlet transform calculation. The two-dimensional CST is then applied to the amplitude of the analytical signal calculated from potential geomagnetic anomaly field data. Mapped maximas of the amplitude of the shearlet transform for the full range of CST scales enable identification of geological discontinuities. The proposed approach avoids reduction to the pole (RTP), which is often problematic in areas with high remanence. It also effectively attenuates the random noise associated with the analytical signal, thereby improving the mapping of magnetic anomalies. Furthermore, it facilitates structural interpretation in geologically complex environments. This process is particularly useful in mining, oil, and geothermal exploration, representing a significant advance in geomagnetic data interpretation.
How to cite: Ouadfeul, S.-A.: Potential geomagnetic field data interpretation using the analytical signal and the two-dimensional continuous Shearlet transform., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-300, https://doi.org/10.5194/egusphere-egu26-300, 2026.
Potential-field geophysical data are commonly used to image geological structures in areas characterized by strong topographic variations, such as volcanic and rift systems. However, the forward modelling of potential-field data using traditional approaches may inadequately represent strongly varying topography if the physical space is not discretized appropriately, potentially biasing inversion results and subsequent geological interpretations. Recent modeling strategies, such as the use of numerical integration schemes within deformable hexahedral elements coupled with an algorithm for local refinement of the forward modeling mesh, have been shown to improve the modeling accuracy while maintaining a reasonable computational cost [Bellounis et al., Geophys. J. Int., ggag009, 2026]. Building on this previous work, we present the implementation of an inversion framework that is consistent with this numerical approach and assess its performance using a series of synthetic data that have not been corrected for topographic effects. The inversion is performed on models discretized using deformable hexahedral elements where physical properties are represented by 2nd order polynomials defined by their values at grid nodes. We first validate the inversion scheme using a model without topography, before considering a second example that incorporates complex topographic variations representative of the Krafla geothermal system in northern Iceland. These synthetic experiments highlight the challenges introduced by topography in the inversion process and demonstrate the improved integration of topographic information enabled by the proposed discretization and inversion strategy. We further examine the influence of the inverse problem regularization parameters on the recovery of subsurface anomalies, thereby providing insights into the advantages and current limitations of the newly implemented inversion framework.
How to cite: Bellounis, L., Brossier, R., Métivier, L., Bouligand, C., and Garambois, S.: Inversion of gravity and magnetic data in the presence of topography using deformable hexahedral elements, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7486, https://doi.org/10.5194/egusphere-egu26-7486, 2026.
Antarctic geothermal heat flow (GHF) is one of the least constrained basal boundary conditions affecting subglacial hydrology and ice sheet dynamics. Furthermore, the paucity of knowledge about GHF hampers our understanding of the linkages between geodynamic evolution and tectono-thermal conditions in Antarctica.
Here we present the results of enhanced spectral analysis of a new Antarctic aeromagnetic anomaly compilation, conformed at long wavelengths with SWARM satellite magnetic data. We apply manual picking of defractal magnetic power spectra on several different major subglacial lake districts in both West and East Antarctica and compare our results with those obtained using automated workflows implemented in PyCurious. Furthermore, we compare our results with independent GHF estimates from seismology, multivariate-similarity approaches and previous magnetic studies.
We show that in the Amundsen Sea Embayment in West Antarctica manual spectral picking resolves the spatial heterogeneity in GHF anomalies better than automated approaches. We newly define a wide coastal region of relatively lower values corresponding to recently inferred mafic intrusions within this sector of the West Antarctic Rift System and higher GHF in the Byrd Subglacial Basin. This is highly significant as it suggests that elevated GHF may contribute to the onset of enhanced ice flow in the interior of the Thwaites Glacier catchment. Additionally, we find localised GHF anomalies in the area of the Thwaites active lakes that may affect subglacial water availability and promote reduced basal shear stress despite the widespread hard bed conditions related to the occurrence of predominantly crystalline rocks.
In East Antarctica, the manual approach confirms the existence of elevated GHF beneath the Dome C subglacial lake district. However, the anomaly is more linear than previously recognised and better aligned with the trend of major aeromagnetic anomalies interpreted as reflecting extensive Paleo to Mesoproterozoic basement in the sector of East Antarctica. Notably, remarkably similar magnetic anomalies are imaged in formerly contiguous Australia where highly radiogenic igneous provinces significantly enhance GHF.
Overall, we find that the choice of appropriate window sizes and spectral ranges coupled with careful inspection of individual power spectra (including the recognition of outliers) and the choice of defractal parameters is important to better define regional scale heterogeneity in Curie Depth estimates. We also find that incorporating the results of independent seismic, multivariate approaches, and expert knowledge in the geological settings of the different study regions is beneficial to better define the realistic ranges of average Curie Depth and for the conversion from Curie Depth to GHF.
The results of our magnetic studies need to be integrated into thermal modelling frameworks together with the evolving knowledge of crustal and lithospheric properties in Antarctica, including intracrustal heat production and sedimentary basin distribution. This approach will yield improved spatial resolution and accuracy of Antarctic GHF and better understanding of the geological origin and significance of major GHF anomalies.
How to cite: Ooi, S. Q., Ferraccioli, F., Latorraca, P., Ford, J., Mather, B., Armadillo, E., Ebbing, J., Eagles, G., Gohl, K., Fullea, J., Verdoya, M., and Green, C.: Enhanced Antarctic geothermal heat flow derived from defractal spectral analysis of aeromagnetic data: examples from the Thwaites Glacier and Dome C regions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11655, https://doi.org/10.5194/egusphere-egu26-11655, 2026.
The basement geology of Yemen is related to the evolution of the late Archean to late Neoproterozoic Arabian-Nubian Shield and contains key records of microplate and island arc accretion during Gondwana assembly. Furthermore, Yemen also preserves important igneous and structural records related to the multi-stage extension and opening of the Gulf of Aden-Red Sea Rift System.
Here we focus on the interpretation of aeromagnetic anomaly data in western Yemen by analysing part of a magnetic anomaly compilation for the whole of Yemen that includes data collected from 26 different airborne surveys flown between 1976 and 1985.
Our reduced to the pole map reveals magnetic anomalies of varying amplitudes and wavelengths, reflecting differences in lithology, structure, and source depth. We applied edge-detection techniques, including tilt angle derivative, total horizontal derivative of the tilt angle, and 3D Euler deconvolution to aid depth to source estimation.
An intriguing result is the newly defined extent of largely buried Cenozoic igneous intrusions that we image from the scant exposures along the southern uplifted rift-related great escarpment to the downthrown block in the northern Tihamah plain. The trend of these anomalies lies at relatively high angle to the rift flank escarpment but is co-linear with some of the trends imaged in the Precambrian basement, suggesting an important role of the inherited structures on much later magma emplacement. To further contextualise our regional results we combine the data from western Yemen with lower resolution publically available data from adjacent sectors of the Arabian shield and the Red Sea Rift and discuss some of the potential tectonic implications.
How to cite: Al-Badani, M. and Ferraccioli, F.: Aeromagnetic Mapping in the Northern Tihamah region, Western Yemen, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19348, https://doi.org/10.5194/egusphere-egu26-19348, 2026.
Mapping crustal thermal structure is fundamental to studies of lithospheric rheology, tectonic evolution, and deep geothermal resource assessment. Curie point depth (CPD) estimates derived from magnetic anomalies are commonly used to infer geothermal gradients, but many approaches remain sensitive to simplifying assumptions about magnetization. Here, a computationally efficient, spatial-domain framework is developed to invert CPD topography by representing the CPD as an effective magnetization-contrast interface and computing its magnetic response using Cauchy-type surface integrals. This formulation replaces three-dimensional volume integration with a two-dimensional surface integral while preserving the governing potential-field physics, which facilitates high-resolution forward modelling and regularized interface inversion. Synthetic experiments are conducted to evaluate numerical accuracy and inversion robustness. The method is applied to magnetic anomalies over the Gonghe Basin on the northeastern Tibetan Plateau, a high-temperature geothermal region. The inverted CPD is interpreted as an effective magnetic-thermal boundary conditional on the assumed susceptibility model, and is compared with results from spectral techniques, equivalent-source reconstructions. Finally, the CPD constraints are integrated with independent geophysical and geological information to construct a three-dimensional temperature model of the Gonghe Basin, which provides quantitative insight into the distribution of thermal anomalies and the likely heat-source characteristics and driving mechanisms.
How to cite: Sun, J. and Liu, S.: Curie Point Depth Inversion From Magnetic Data Using a Cauchy-type Integral Interface Framework: Application to the Gonghe Basin (northwest China), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8781, https://doi.org/10.5194/egusphere-egu26-8781, 2026.
The Weilastuo tin polymetallic deposit is located in the central-southern segment of the Great Xing’an Range, which is an important metallogenic belt of northern China. The Quaternary is widely distributed in the ore district, with the host rocks primarily consisting of migmatitic gneisses and a small amount of Carboniferous quartz diorite. The ore-related intrusive bodies are concealed at depths within the tin-zinc ore district, with the shallowest occurrences reaching approximately 400m below the surface. This study collected the rock samples from the Weilastuo and other districts, and accurately measured the physical properties parameters including resistivity, polarization, magnetic susceptibility, and natural remanent magnetization for over 480 rock samples. The research conducted multi-geophysical explorations and methodological experiments in the Weilastuo ore district, including surface and airborne magnetic exploration, audio magnetotellurics (AMT), and transient electromagnetic (TEM). The 3D magnetic susceptibility and resistivity structure model of the Weilastuo ore district were constructed, providing geophysical constraints for developing geophysical exploration models for shallow cover polymetallic tin deposits of Inner Mongolia, China. This study was supported by project grant no. 2024ZD1001502.
How to cite: Liu, S., Peng, R., Han, B., Liu, Y., Yang, T., and Zhou, Z.: The magnetic and electromagnetic integrated geophysical investigation of the Weilasituo tin polymetallic deposit, Inner Mongolia, China, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9535, https://doi.org/10.5194/egusphere-egu26-9535, 2026.
The Sn-W belt of western Iberia coincides with large-scale magnetic anomalies, namely the Porto-Veira-Guarda and the Central System Magnetic Anomalies (PVGMA and CSMA) challenging the well-known relationship between Sn ores and ilmenite (non-magnetic) granites. In fact, these magnetic anomalies overlap a series of gneiss domes developed in the latest stages of Variscan evolution and often hosting local, but abundant critical mineral ores. Paradoxically, these domes are cored by non-magnetic granites and their by-products, rising the question about the source of the magnetism.
With the goal of unravelling the relationship between mineralization, tectonics and magnetic anomalies, we have carried out a 50 x 50 km2 ground potential field survey in the Martinamor Gneiss Dome and its surroundings, to the southwest of Salamanca. Results from analytical processing and modelling show that shallow and local magnetic anomalies respond to the existence of highly magnetic, albeit uncommon, Upper-Proterozoic to Ordovician metasediments that are not related to the younger (338-300 Ma) Sn-W mineralization. Contrarily, the ores appear at the non-magnetic core of the dome and are frequently related to high gradient zones within potential field data. The latter coincide with the location of extensional detachments that must have acted as pathways for mineralizing fluids. To the southwest of the study area and at higher depths, conspicuous magnetic maxima coincide with Bouguer gravity anomaly maxima and with high shear-wave velocity anomalies, pointing out to the existence of non-outcropping mafic rocks. These lithologies might be progressively more common at depth and be the source of the long wavelength PVGMA and CSMA.
The present dataset indicates that, as it has been generally acknowledged, magnetic rocks do not host Sn (and W) mineralization but regardless of this evidence, in western Iberia, there might be a common mechanism that triggers mineralization and magnetization. Constraining the age of the latter is key to further interpret this area.
This research has been funded by project SA066P24 from the JCYL
How to cite: Ayarza, P., Durán, M., Calvín, P., DeFelipe, I., Yenes, L., Santamaria, A., Palomeras, I., Sanchez Sanchez, Y., Yenes, M., Carbonell, R., and Gomez Barreiro, J.: Potential field and structural control of a Sn-W rich area, W Iberia (Central Iberian Zone), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6661, https://doi.org/10.5194/egusphere-egu26-6661, 2026.
Gravity‐Derived Moho Depth of Egypt: Insights from Lithospheric-Scale Gravity Inversion and Comparison with Global Crustal Models
Mohammad Shehata1,2, Hakim Saibi1
1Geosciences Department, College of Science, United Arab Emirates University, 15551, Al-Ain, United Arab Emirates
2Department of Geology, Faculty of Science, Port Said University, Port Said 42522, Egypt
Reliable constraints on Moho depth are fundamental for understanding lithospheric structure and tectonic evolution, yet estimates across Egypt and northeastern Africa remain uneven in coverage and resolution. Seismic constraints are restricted to discrete locations, while global crustal models mainly capture long-wavelength features and may not resolve crustal thickness contrasts across different tectonic domains. Here we present a country-scale Moho depth model for Egypt derived from GOCE satellite gravity, providing continuous regional coverage for evaluating tectonically controlled crustal thickness variations.
Bouguer gravity anomalies were computed from GOCE satellite gravity data, complemented where appropriate by terrestrial observations, and corrected for topography, bathymetry, and sedimentary cover. Moho geometry was estimated using frequency-domain Parker–Oldenburg iterative inversion incorporating laterally variable crust–mantle density contrasts derived from the CRUST1.0 model, allowing spatial variations in crustal composition and thickness to be explicitly accounted for (Shehata and Mizunaga, 2022). The resulting Moho model reveals systematic crustal thickness variations that closely correspond to Egypt’s tectonic architecture, with shallow Moho depths (~18–22 km) beneath extensional domains associated with Red Sea rifting, intermediate depths (~28–34 km) in transitional zones such as the Nile Delta and Sinai, and thick crust (>40–43 km) across the Western Desert and southern Egypt. Sharp lateral Moho gradients delineate boundaries between these regimes, indicating localized strain accommodation during rift development. Comparison with CRUST1.0 (Laske et al., 2013), GEMMA (Reguzzoni et al., 2013), and the seismic-based Moho compilation of Tugume et al., 2013) shows overall agreement at long wavelengths, while localized deviations occur in rifted and transitional regions due to differences in data resolution and methodological sensitivity. These results demonstrate that tectonic regime exerts a first-order control on Moho depth beneath Egypt and highlight the value of GOCE-based gravity inversion for improving lithospheric characterization in regions of limited seismic coverage.
References
Laske, G., Masters, G., Ma, Z., Pasyanos, M., 2013. Update on CRUST1. 0—A 1-degree global model of Earth’s crust, in: Geophysical Research Abstracts. p. 2658.
Reguzzoni, M., Sampietro, D., Sansò, F., 2013. Global Moho from the combination of the CRUST2. 0 model and GOCE data. Geophys. J. Int. 195, 222–237.
Shehata, M.A., Mizunaga, H., 2022. Moho depth and tectonic implications of the western United States: insights from gravity data interpretation. Geosci. Lett. 9, 23.
Tugume, F., Nyblade, A.A., Julia, J., Van der Meijde, M., 2013. Crustal shear wave velocity structure and thickness for Archean and Proterozoic terranes in Africa and Arabia from modeling receiver functions, surface wave dispersion, and satellite gravity data. Tectonophysics 609, 250–266.
How to cite: Shehata, M. and Saibi, H.: Gravity‐Derived Moho Depth of Egypt: Insights from Lithospheric-Scale Gravity Inversion and Comparison with Global Crustal Models, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12524, https://doi.org/10.5194/egusphere-egu26-12524, 2026.
Microgravity surveying is a high-resolution geophysical technique widely used for detecting subsurface voids, karst features, and localized density variations in engineering, environmental, and geological investigations. However, in complex environments such as steep mountainous terrain, narrow valleys, and urban or built-up areas, standard terrain correction approaches often fail to adequately account for fine-scale topographic variations and man-made structures. These limitations can introduce significant distortions in Bouguer anomalies, particularly at the microGal sensitivity level required for microgravity applications.
This research presents an enhanced terrain correction methodology specifically tailored for microgravity surveys conducted in complex natural and artificial environments. The proposed approach integrates high-resolution elevation data derived from Digital Terrain Models (DTMs), conventional topographic surveys, and 3D LiDAR datasets to construct detailed compartmentalized mass models around each gravity observation point. Surrounding terrain and structures are discretized into three-dimensional volumetric compartments characterized by spatial position, elevation, size, and density. Unlike conventional methods, the approach allows the assignment of variable densities to individual compartments, enabling accurate representation of heterogeneous materials such as rock, air-filled voids, buildings, and structural components.
Gravitational acceleration contributed by each compartment is calculated using Newtonian gravity principles, and the vertical component relevant to terrain correction is extracted and summed to compute station-specific corrections. The methodology is implemented using a database-driven computational framework to efficiently handle the large number of calculations involved. Results demonstrate that the proposed technique significantly improves terrain correction accuracy, effectively capturing the gravitational influence of steep slopes, narrow valleys, and complex urban infrastructure. The integration of 3D LiDAR-derived models enhances spatial resolution and supports microGal-level precision. The proposed compartmentalized terrain correction approach provides a scalable, automated, and accurate alternative to traditional methods, offering substantial benefits for microgravity investigations in rugged terrain and densely built environments.
How to cite: Shahzad, S. and Jadoon, K. Z.: A Compartmentalized Elevation Model Approach to Terrain Correction in Microgravity Surveys, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13520, https://doi.org/10.5194/egusphere-egu26-13520, 2026.
Abstract. The Bohai Sea and its adjacent areas (116.5°~123.5°E, 36.5°~41.5°N) are located in eastern China, serving as a critical marine-continental transition zone in the eastern part of the country. Acquiring high-precision distribution characteristics of the Moho depth in this region is of great significance for understanding the local deep tectonic features and the distribution of mineral resources such as oil and gas. Owing to the high cost of seismic surveys, it is difficult to obtain the overall Moho topography of the region. Therefore, based on the latest generation of SWOT-03 satellite gravity data, this study uses the improved Bott-Parker method to invert a high-resolution Moho topography with a resolution of 1′×1′ in the Bohai Sea and its adjacent areas. First, Bouguer correction was applied to the SWOT-03 free-air gravity anomalies to derive the Bouguer gravity anomalies of the study area. To separate the Moho gravity anomalies, which reflect the distribution characteristics of the Moho depth, from the Bouguer gravity anomalies, an 8th-order wavelet multiscale decomposition was performed on the Bouguer gravity anomalies, generating the corresponding wavelet approximations and wavelet details. Then, the average radial logarithmic power spectrum analysis method was used to calculate the approximate source depths of the wavelet details of each order, thus obtaining the gravity anomalies that represent Moho undulation. Finally, the improved Bott-Parker method was employed to invert the high-resolution Moho topography of the Bohai Sea and its adjacent areas. Specifically, the improved Bott-Parker method obtains the initial Moho topography via linear regression using known seismic Moho data and Moho gravity anomalies derived from wavelet multiscale decomposition, and then continuously corrects the Moho topography using the gravity difference between the forward-calculated values from the Parker method and the observed gravity values. Compared with the traditional Parker-Oldenburg method, the improved Bott-Parker method avoids the need to set the cutoff frequency of the filter. The results demonstrate that the average Moho depth in the Bohai Sea and its adjacent areas is 32.98 km, with a variation range of 24.26~57.22 km, and multiple Moho uplift and depression zones are present in the region. The inverted Moho topography is basically consistent with the Crust1.0 global crustal model, which can well reflect the distribution characteristics of the Moho depth in the Bohai Sea and its adjacent areas as a whole. This study has certain guiding significance for understanding the regional tectonic features and conducting oil and gas exploration.
Keywords: SWOT-03 satellite gravity data; Moho depth; Gravity inversion; Wavelet multi-scale decomposition；Improved Bott-Parker method
How to cite: Lan, G., Cao, J., Xiong, Z., Luo, K., Yu, R., Cai, S., Guo, Y., and Wu, M.: An Inversion Method for Moho Depth Distribution Characteristics in the Bohai Sea and Its Adjacent Areas Based on the Improved Bott-Parker Method, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18750, https://doi.org/10.5194/egusphere-egu26-18750, 2026.
We propose an innovative approach for the interpretation of time-lapse gravity data aimed at estimating subsurface mass variations associated with CO2 injection and storage. The method is based on the Extremely Compact Source (ECS) inversion technique (Maiolino et al., 2024), which is used to isolate the individual contributions of discrete CO2 mass accumulations in the subsurface and to quantify their associated excess mass.
To date, ECS inversion has been primarily applied as a filtering strategy to remove regional-scale contributions from potential field data or to separate the effects of closely spaced sources. The approach relies on an iterative inversion of potential field observations to derive a subsurface model composed of source distributions with minimal volumetric extent, referred to as atoms, simultaneously ensuring a low data misfit. A key advantage of the method is that it does not require any a priori information about subsurface properties.
Once the ECS model is obtained, the excess mass associated with each source contributing to the observed gravity anomaly can be readily computed. In this study, we demonstrate that the proposed approach enables precise identification of CO2 accumulations within the reservoir and allows for accurate estimation of net mass variations related to both stored CO2 and leakage occurring along permeable fault zones.
How to cite: Milano, M., Ianniello, A., Maiolino, M., Bianco, L., and Fedi, M.: Quantitative Assessment of CO2 Leakage Using Time-Lapse Gravity Inversion, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21850, https://doi.org/10.5194/egusphere-egu26-21850, 2026.
Data-driven deep learning inversion of gravity and magnetic data is an emerging technique in obtaining subsurface density and magnetization source distributions. However, the absence of geophysical constraints, inflexibility of structural coupling and oversimplified features of synthetic data restrict the data-driven deep learning joint inversion, outputting models inconsistent with geophysical observations and geological priors. We propose a physics-informed deep learning framework for joint inversion of gravity and magnetic data. The data-driven pre-training is initially utilized by conducting end-to-end supervised training, learning the synthetic features from training dataset. With inverted density and magnetization distributions using pre-trained network, the data misfit and structural losses are calculated for physics-informed fine-tuning of the network. The embedment of physics-informed fine-tuning optimizes data-driven pre-trained network while retaining swift model reconstruction ability, generating models with improved data fitting and model reconstruction of the consistent source regions. The proposed framework is tested on two sets of synthetic examples with different structural homologies and applied to the field data of the Jining iron deposit (northern China). The joint inversion generates density and magnetization distributions for hematite and magnetite and indicates the possibile presence of a regional magnetic basement caused by the high-susceptibility amphibole magnetite quartzite in the Taishan Group. The proposed physics-informed deep learning framework for joint inversion demonstrates the potential of integrating multiple geophysical data and enhances the geophysical consistency in geological modeling.
How to cite: Yan, X., Liu, S., and Lv, M.: A Deep Learning Framework for Joint Inversion of Gravity and Magnetic Data, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12390, https://doi.org/10.5194/egusphere-egu26-12390, 2026.
Posters virtual: Mon, 4 May, 14:00–18:00 | vPoster spot 1a
EGU26-2063 | Posters virtual | VPS29
Unveiling concealed Banded Magnetite Quartzites (BMQs) through high-resolution aeromagnetic surveys: New insights from the Nellore Schist belt of Eastern Dharwar Craton, IndiaMon, 04 May, 14:03–14:06 (CEST) vPoster spot 1a
In the Chundi–Malakonda–Ayyavaripalle region of the Nellore Schist Belt, part of the Dharwar Craton, six north-south (N–S) trending, elongated Banded Magnetite Quartzite (BMQ) bands have been identified. These bands are exposed within meta-rhyolite and quartzite formations and are associated with biotite–muscovite schist. The BMQs vary in width from 20 to 40 meters and extend in length from 1.5 to 4.5 kilometres. High-resolution aeromagnetic surveys with a terrain clearance of 80 meters have revealed significant magnetic anomalies over the study area (source: https://geodataindia.gov.in). These anomalies range from –3,900 to +5,000 nanoteslas (nT), indicating a high concentration of magnetic minerals within the exposed BMQs, designated as Bands 1 to 6. In addition to these exposed bands, a concealed, parallel, N–S trending BMQ band has been identified through detailed analysis of aeromagnetic data. 2D and 3D Interpretation of the magnetic anomalies suggests that meta-rhyolites exist up to an average depth of 250 m from the surface and might be associated with BIF bands at depth. This depth extent highlights the substantial vertical continuity of the magnetite-rich formations in the region. The integration of geological mapping and aeromagnetic data provides a comprehensive understanding of subsurface geology, highlighting the potential for significant mineralization within the Nellore Schist Belt.
How to cite: Dharavathu, S., Kosuri, S. K., Vappangi, P. K., and Kumar, P.: Unveiling concealed Banded Magnetite Quartzites (BMQs) through high-resolution aeromagnetic surveys: New insights from the Nellore Schist belt of Eastern Dharwar Craton, India, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2063, https://doi.org/10.5194/egusphere-egu26-2063, 2026.
