Acta Geodaetica et Geophysica最新文献

{"title":"Comparison of geoid determination methods in the central part of Ethiopia","authors":"Zenebe Ayele Gebrekidan,&nbsp;Andenet Ashagrie Gedamu,&nbsp;Mesay Tefera Kassaw","doi":"10.1007/s40328-026-00501-9","DOIUrl":"10.1007/s40328-026-00501-9","url":null,"abstract":"<div><p>Determining the geoid gravimetrically poses challenges which are complex mathematical computation and variability representation of the Earth, particularly when precision is necessary. This study aimed to compare the geoid determination methods namely: least squares collocation (LSC), Stokes integral, and Hotine integral methods. Shuttle Radar topography mission (SRTM), gravity anomaly, gravity disturbance, Earth gravity model 2008 (EGM2008), and global navigation satellite systems with levelling (GNSS/Levelling) data were used for the purpose of geoid determination methods. The LSC method was applied using the RCR technique. Whereas Stokes and Hotine integrals methods were computed based on KTH approach with essential corrections, including topographic, atmospheric, ellipsoidal, and downward continuation refinements. All three approaches yielded consistent geoid models with validation against benchmarks produced standard deviations of 0.069 m for LSC, 0.062 m for Stokes, and 0.061 m for Hotine. The findings demonstrate that the LSC provides reliable geoid approximations, Stokes and Hotine integrals attain marginally higher precision. This study highlights the significance of integrating airborne gravity data with global geopotential models and determined the gravimetric geoid model to contribute the development of an accurate nationwide vertical reference for Ethiopia.</p></div>","PeriodicalId":48965,"journal":{"name":"Acta Geodaetica et Geophysica","volume":"61 3","pages":"459 - 479"},"PeriodicalIF":2.6,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148965399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated gravity forward and inversion modeling for subsurface characterization in conductive zones of Gujarat, India","authors":"Kelvy P. Dalsania,&nbsp;Anirbid Sircar,&nbsp;Satyam Shinde","doi":"10.1007/s40328-026-00489-2","DOIUrl":"10.1007/s40328-026-00489-2","url":null,"abstract":"<div><p>Gravitational methods offer a cost effective and robust approach for delineating subsurface structures, particularly in tectonically complex or volcanically covered terrains where other geophysical tools are limited. This study develops and applies an integrated forward-inversion workflow to investigate concealed mass anomalies in Unai geothermal field, located along the western flank of the Narmada-Son Lineament, southern Gujarat. The methodology combines analytical forward modeling of buried spherical body, polynomial detrending to remove regional trends, sinusoidal correction for oscillatory residuals and a damped Gauss-Newton inversion scheme with Tikhonov regularization to recover geologically plausible parameters. Synthetic testing of the inversion framework yielded parameters estimated with &lt; 1% error and a Root Mean Square (RMS) misfit of 0.0286 mGal, confirming numerical stability and accuracy under controlled conditions. Application to the field gravity data from Unai achieved a close fit to observed anomalies (RMS ≈ 0.052 mGal), with recovered parameters indicating a high density body (~ 2569 kg/m³), and at ~ 97 m depth and ~ 83 m radius. The oscillatory residual corrections revealed signatures consistent with fracture-controlled pathways and lithological discontinuities. These features align with mapped faults, exposed lithology and active hot spring manifestations suggesting intrusive or crystalline units acting as both heat sources and structural controls for hydrothermal circulation. The integrated results highlight the role of shallow intrusive bodies and fractures basalts in sustaining geothermal activity, while also underscoring their dual potential for geothermal development and groundwater resource evaluation. By demonstrating the accuracy of the workflow on synthetic data and its geological consistency in field, this study provides a replicable, computationally efficient and geologically meaningful framework for gravity based subsurface characterization in geothermal provinces.</p></div>","PeriodicalId":48965,"journal":{"name":"Acta Geodaetica et Geophysica","volume":"61 2","pages":"337 - 355"},"PeriodicalIF":1.8,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LEO-based interpolation methods comparison for regional augmented PPP","authors":"Jing Fang,&nbsp;Rui Tu,&nbsp;Runzhi Zhang,&nbsp;Fang Cheng,&nbsp;Xiaochun Lu","doi":"10.1007/s40328-026-00495-4","DOIUrl":"10.1007/s40328-026-00495-4","url":null,"abstract":"<div>\u0000 \u0000 <p>In this study, a low-Earth orbit (LEO) constellation of 160 LEO satellites was simulated, and simulated LEO observations from American regional stations were used to investigate regional augmented precise point positioning (PPP). For reference networks with scales of 75 km and 165 km, the low-order surface model (LSM), the distance-based linear interpolation method (DIM), and the modified linear combination model (MLCM) were respectively used to interpolate atmospheric delays. For both scales of the reference networks, the root mean square errors (RMSEs) of the inter-satellite single-difference (SD) ionospheric slant delay residuals and the tropospheric zenith wet delays (ZWDs) residuals interpolated by the three methods were respectively less than 2.00 cm and 0.25 cm, and the accuracy of the atmospheric delays interpolated by the three methods was comparable. Within the 75‑km and 165‑km reference networks, using the interpolated atmospheric delays to constrain undifferenced and uncombined (UDUC) PPP improved the positioning performance of both the float and fixed solutions, and also augmented the ambiguity resolution (AR) performance of the fixed solutions. The enhancement effects of the three methods were comparable, and the enhancement effect decreased slightly as the scale of the reference network increased. Among the three methods, LSM performed slightly better than DIM and MLCM in the up direction, since the LSM used in this study is an interpolation model that accounts for the elevation factor.</p>\u0000 </div>","PeriodicalId":48965,"journal":{"name":"Acta Geodaetica et Geophysica","volume":"61 2","pages":"287 - 313"},"PeriodicalIF":1.8,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on evaluation of geometric parameters of shale hydraulic fractures based on electromagnetic three-parameters","authors":"Xijin Song,&nbsp;Jinliang Zhao,&nbsp;Li Guo,&nbsp;Changzan Liu,&nbsp;Qinyang Li","doi":"10.1007/s40328-026-00492-7","DOIUrl":"10.1007/s40328-026-00492-7","url":null,"abstract":"<div><p>Hydraulic fracturing can improve the permeability of shale reservoirs, and accurately acquiring post-fracturing fracture geometric parameters is critical for optimizing subsequent development plans and enhancing hydrocarbon recovery efficiency. This study presents a monitoring method using three electromagnetic parameters based on a single-transmitter and double-receiver coil system in a horizontal borehole. By establishing a finite-element fracture geoelectric model, the study investigates the influence of coil source distance and tool eccentricity on the three electromagnetic parameters, as well as their response characteristics under different fracture parameters. Results show that increasing the coil source distance broadens the response peak width of the three electromagnetic parameters; tool eccentricity has a more significant effect on the parameters at small source distances. The three electromagnetic parameters exhibit distinct resolution capabilities for fracture geometry: The real-part amplitude ratio offers the best resolution for fracture dip angles, the phase difference is most sensitive to changes in fracture length, and the apparent conductivity is most sensitive to variations in fracture width. Additionally, co-axial monitoring of transmitter and receiver coils cannot distinguish fractures with complementary dip angles, whereas when the two receiver coils are tilted during monitoring, all three electromagnetic parameters can effectively distinguish such fractures. This method leverages the differential sensitivity of the three electromagnetic parameters to fracture dip angle, length, and width, selecting the most suitable electromagnetic parameter for precise evaluation according to different fracture parameters and verifying results using the remaining two parameters. It provides a new solution for evaluating shale fracturing effects.</p></div>","PeriodicalId":48965,"journal":{"name":"Acta Geodaetica et Geophysica","volume":"61 2","pages":"249 - 271"},"PeriodicalIF":1.8,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction: Adjustment of numerous measurements in steps","authors":"Jason Koci,&nbsp; Georgios Panou","doi":"10.1007/s40328-026-00499-0","DOIUrl":"10.1007/s40328-026-00499-0","url":null,"abstract":"","PeriodicalId":48965,"journal":{"name":"Acta Geodaetica et Geophysica","volume":"61 2","pages":"379 - 381"},"PeriodicalIF":1.8,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40328-026-00499-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning-augmented climate models for predicting groundwater stress zones in Sub-Saharan Africa","authors":"Joseph Omeiza Alao,&nbsp;Momohjimoh Abdulsalami,&nbsp;Kazah A. Kogi","doi":"10.1007/s40328-026-00497-2","DOIUrl":"10.1007/s40328-026-00497-2","url":null,"abstract":"<div>\u0000 \u0000 <p>Groundwater supplies more than 70% of water demand in SSA regions, but is increasingly under threat from climate change and population growth. Conventional groundwater models are data-intensive and not appropriate for Sub-Saharan Africa (SSA) contexts. This systematic review assesses Machine Learning-Augmented Groundwater Models (ML-AGMs) such as Random Forest, XGBoost, and LSTM algorithms to predict groundwater stress zones with minimal data inputs and satellite-based climate data. Several peer-reviewed articles (2015–2025) were analyzed to assess the efficacy, applicability, and scalability to SSA regions. Findings reveal that ML-AGMs provided excellent prediction potential (RMSE error range: 0.356–0.372 m; R-squared: 0.503–0.679) with minimal data inputs. This represents an important innovation where data-scarce groundwater modeling is possible and dynamic. Google Earth Engine and QGIS enhance spatiotemporal analysis and improve communication with stakeholders. However, this review also highlights limitations of ML-AGM concerning data quality, applicability issues, and ethical considerations. Further research recommendations include hybridized models and inclusion of socioeconomic factors. ML-AGM and applications provide scalable and enhanced Sustainable Development Goal (SDG) 6 implementation. However, issues and limitations persist with aquifer diversity and the equitable application of groundwater stress assessments.</p>\u0000 </div>","PeriodicalId":48965,"journal":{"name":"Acta Geodaetica et Geophysica","volume":"61 2","pages":"177 - 197"},"PeriodicalIF":1.8,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning-based estimation of specific yield in single-well unconfined aquifers","authors":"Zahra Dashti,&nbsp;Mohammad Nakhaei,&nbsp;Meysam Vadiati,&nbsp;Gholam Hossein Karami,&nbsp;Ozgur Kisi","doi":"10.1007/s40328-026-00496-3","DOIUrl":"10.1007/s40328-026-00496-3","url":null,"abstract":"<div>\u0000 \u0000 <p>Accurate determination of hydrodynamic parameters holds immense significance in achieving sustainable development objectives and ensuring comprehensive water resources management. This research aims to assess the performance of machine learning models in estimating specific yield using hydrogeological data and pumping test data in the single well system for the unconfined alluvial aquifers of Iran’s central plateau. Artificial neural network, gene expression programming, adaptive neuro-fuzzy inference system, fuzzy logic, least square support vector machine, and group method of data handling were used to estimate specific yield. In order to accomplish this objective, data from pumping tests and hydrogeological evaluations conducted on 83 wells located in the central plateau of Iran were gathered and normalized. The available data was utilized to generate different combinations as input for the models. Subsequently, 70% of the data was selected for the training phase, while the remaining 30% was allocated for the testing phase. The precision of the models was evaluated by employing mean absolute error, root mean square error, and correlation coefficient. The performance criteria indicated that while all of the machine learning models are promising tools for rapid and dependable specific yield estimation, the group method of data handling model exhibited the highest level of accuracy. The results indicated that combination 3 (well discharge, the slope of the initial and final sections of the time-drawdown graph, minimum and maximum drawdown data, water depth, the distance of the observation well from the pumping well, and hydraulic conductivity) was the most effective in estimating specific yield.</p>\u0000 </div>","PeriodicalId":48965,"journal":{"name":"Acta Geodaetica et Geophysica","volume":"61 2","pages":"315 - 336"},"PeriodicalIF":1.8,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40328-026-00496-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Instance segmentation of different spatial resolution satellite images with Mask R-CNN integration","authors":"Betul Saralioglu Lacinoglu,&nbsp;Oguz Gungor,&nbsp;Ekrem Saralioglu","doi":"10.1007/s40328-026-00498-1","DOIUrl":"10.1007/s40328-026-00498-1","url":null,"abstract":"<div>\u0000 \u0000 <p>Recent advancements in remote sensing technologies have enabled the acquisition of large volumes of high-resolution spatial data. However, the classification of complex datasets remains challenging using traditional methods. This study investigates the potential of Mask R-CNN and its variants for advancing the classification of satellite imagery with diverse resolutions and classes. The key advantages of the model, including transferability across regions, high accuracy, and rapid processing when trained on sufficiently large datasets, offer a novel solution beyond traditional methodologies. Extensive experiments were performed on novel datasets containing 1515 images and 18,811 annotated labels generated from Sentinel-2 and WorldView-3 satellite images. In instance segmentation tasks for urban area detection on Sentinel-2 imagery, Mask R-CNN F1 scores of 0.81 and 0.79 were achieved using ResNet-101 and ResNet-50 backbones, respectively. For the multi-class land cover instance segmentation (five classes) of Sentinel-2 data, the model attained an F1 score of 0.75. Finally, building segmentation on WorldView-3 imagery yielded a score of 0.84. The results demonstrate that the proposed methodology can effectively classify satellite images with diverse characteristics and resolutions. This study provides a methodological baseline for potential geographical adaptability, enabling the model to process images across diverse contexts, which is a critical step toward scalable remote sensing applications. The findings highlight the model’s transfer learning capacity and multi-scale data processing proficiency, positioning it as a versatile tool for tasks ranging from land cover mapping to urban monitoring.</p>\u0000 </div>","PeriodicalId":48965,"journal":{"name":"Acta Geodaetica et Geophysica","volume":"61 3","pages":"415 - 436"},"PeriodicalIF":2.6,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148965484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intersections search in marine gravity or magnetic survey network: base on binary search","authors":"Fanxiang Zeng,&nbsp;Xudong Zhang,&nbsp;Tingting Wu","doi":"10.1007/s40328-026-00494-5","DOIUrl":"10.1007/s40328-026-00494-5","url":null,"abstract":"<div><p>This study introduces an innovative binary search method for calculating intersection point discrepancies in marine gravity and magnetic survey lines, significantly enhancing the efficiency and accuracy of data processing. The discrepancies at the intersections of survey lines are critical for evaluating the quality of geophysical measurements and serve as essential data for network adjustments and compensation. Traditional methods often suffer from high computational complexity or slow processing speeds, which hinders the rapid and accurate identification of all intersection points. To address these limitations, we propose a binary search approach that efficiently narrows down the search range, significantly reducing the number of data points required for intersection detection. Our method combines mathematical formulas for initial intersection detection with an iterative binary search process, allowing for quick localization of intersection points. The experimental results demonstrate the effectiveness of this approach, achieving a 100% success rate in detecting 175 intersection points within 0.295 s for a large-scale marine gravity survey project with over 1.5 million data points. This method not only improves computational efficiency but also ensures high accuracy, making it highly suitable for various geophysical surveys, including marine gravity, magnetic, and airborne surveys. Recent studies have also highlighted the importance of efficient intersection detection in modern geophysical surveys, further validating the practical significance of this research.</p></div>","PeriodicalId":48965,"journal":{"name":"Acta Geodaetica et Geophysica","volume":"61 2","pages":"273 - 286"},"PeriodicalIF":1.8,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adjustment of numerous measurements in steps","authors":"Jason Koci,&nbsp;Georgios Panou","doi":"10.1007/s40328-026-00493-6","DOIUrl":"10.1007/s40328-026-00493-6","url":null,"abstract":"<div><p>A technique for addressing adjustment problems involving large data sets is developed. The adjustment-in-steps approach of the least-squares method, applied to observation adjustments only, is optimized. The core idea of the optimization process is to group the condition equations in a way that minimizes the computational effort required for adjustments. A detailed theoretical framework of the adjustment-in-steps technique is refined, covering both linear and non-linear condition equations. In addition, an optimization methodology is developed to support the implementation of the proposed technique. Numerical experiments, including line-fitting and the determination of equipotential curves, are conducted. The proposed technique is implemented in the C programming language, and the results demonstrate its numerical equivalence and improved computational efficiency compared to the classical method.</p></div>","PeriodicalId":48965,"journal":{"name":"Acta Geodaetica et Geophysica","volume":"61 2","pages":"357 - 377"},"PeriodicalIF":1.8,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40328-026-00493-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148196274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}