Journal of Applied Geophysics最新文献

{"title":"Nanometer-sized magnetite and its impact on 1H NMR petrophysical characterization of synthetic carbonates","authors":"Jonatã Barbosa Teixeira ,&nbsp;Gabriella Fazio ,&nbsp;Silvia Lorena Bejarano Bermudez ,&nbsp;Ângela Leão Andrade ,&nbsp;Vitor Emmanuel Paes Silveira ,&nbsp;Agide Gimenez Marassi ,&nbsp;Mariane Candido ,&nbsp;Arthur Gustavo de Araújo Ferreira ,&nbsp;José Domingos Fabris ,&nbsp;Luiz Carlos Bertolino ,&nbsp;Marco Antônio Rodrigues de Ceia ,&nbsp;Daniel Ribeiro Franco ,&nbsp;Tito José Bonagamba ,&nbsp;Ricardo Ivan Ferreira Trindade","doi":"10.1016/j.jappgeo.2025.106058","DOIUrl":"10.1016/j.jappgeo.2025.106058","url":null,"abstract":"<div><div>Magnetic minerals, such as magnetite, can significantly influence ¹H Nuclear Magnetic Resonance (NMR) measurements, introducing biases that can affect petrophysical interpretations in reservoir rocks. Understanding these effects is crucial for improving the accuracy of fluid content estimations in subsurface evaluations. In this study, we investigate how nanometric-sized magnetite impacts T₂ relaxation times in synthesized carbonate samples with controlled porosity and magnetite concentrations. Twelve carbonate samples were synthesized with varying magnetite content (0.0 %–0.8 % wt.), ensuring a controlled environment for evaluating NMR responses. These samples underwent petrophysical (bulk volume, pore volume, grain density, and NMR), mineralogical (XRD and SEM-EDS), and magnetic (low-field magnetic susceptibility, hysteresis loop, FORC, and IRM measurements) characterization to ensure the integrity of both the synthesis and the magnetite contamination. Our findings indicate that (1) the synthesis successfully produced samples with consistent properties, showing a decrease in pore volume with increasing cementing fluid and a corresponding enhancement of magnetic properties with higher magnetite contamination; (2) ¹H NMR-based porosity estimates were significantly affected by magnetite contamination, displaying a noticeable flattening of T₂ relaxation curves and a reduction in relaxation times, likely due to enhanced diffusional effects; and (3) increasing magnetite concentrations induced nonlinear distortions in porosity ϕ_NMR, leading to systematic deviations from expected values and, consequently causing porosity underestimation. These results underscore the need to account for magnetic mineral contamination in NMR analyses of carbonate reservoirs and highlight the importance of controlled research into magnetite's impact on petrophysical assessments.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"245 ","pages":"Article 106058"},"PeriodicalIF":2.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electrical resistivity inversion based on the minimum support gradient functional for water-bearing structure in tunnel","authors":"Zhaoyang Deng ,&nbsp;Shuo Zhang ,&nbsp;Pengyu Jing ,&nbsp;Lichao Nie ,&nbsp;Shilei Zhang","doi":"10.1016/j.jappgeo.2025.106039","DOIUrl":"10.1016/j.jappgeo.2025.106039","url":null,"abstract":"<div><div>Electrical resistivity tomography plays a critical role in the investigation of tunnel water and mud inrush, but its inversion is an ill-posed and non-unique problem that requires regularization. Traditional smooth regularization ensures the overall stability of the inversion and provides continuous, smooth results. However, when applied to tunneling, especially in areas with clear geological boundaries (e.g. faults, karst cave), it is limited in its ability to produce sharp boundaries and blocky features. To address this limitation, this study incorporates a focusing regularization technique—the Minimum Support Gradient (MSG) functional—into a tunnel resistivity inversion framework. We first analyze the composition of several regularization terms and highlight the advantages of MSG in preserving sharp structural boundaries. Numerical simulations of typical water-bearing structures demonstrate that the proposed method effectively delineates the geometry of water-rich features and achieves improved resistivity recovery. In addition, the method was successfully applied to the Central Yunnan Water Diversion Project, where it effectively identified water-bearing structures in front of the tunnel face.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"245 ","pages":"Article 106039"},"PeriodicalIF":2.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145625387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automatic velocity spectrum picking method based on a layer-wise fusion strategy","authors":"Xiaodong Sun ,&nbsp;Xichao Shi ,&nbsp;Pengjie Xue ,&nbsp;Ning Qin","doi":"10.1016/j.jappgeo.2025.106031","DOIUrl":"10.1016/j.jappgeo.2025.106031","url":null,"abstract":"<div><div>The accuracy of seismic velocity analysis critically determines the quality of seismic data imaging. However, traditional manual picking methods suffer from low efficiency, while existing automated techniques often fail to effectively capture the multiscale characteristics of seismic data. To address these challenges, this paper proposes an automatic velocity spectrum picking method based on layer-wise multimodal fusion(MMNet). The approach constructs a multimodal neural network architecture based on U-Net, employing a layer-wise fusion strategy to hierarchically integrate features from both velocity spectra and Common Middle Point(CMP) gathers, thereby enhancing multiscale feature extraction. Furthermore, the method incorporates Transformer modules with multi-head attention mechanisms to achieve efficient parallel processing and semantic understanding of multimodal data. Experimental results on both 2D/3D synthetic models and field datasets demonstrate that the proposed method outperforms conventional approaches in terms of picking accuracy, noise resistance, and computational efficiency, providing a more reliable automated solution for seismic data processing.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"245 ","pages":"Article 106031"},"PeriodicalIF":2.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145625389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Methods and applications of potential field modeling of finite distributions","authors":"Dimitrios Tsoulis ,&nbsp;Georgia Gavriilidou ,&nbsp;Maria Tsagkalidou ,&nbsp;Mohammad Poursina ,&nbsp;Alex Ho ,&nbsp;Margrethe Wold","doi":"10.1016/j.jappgeo.2025.106066","DOIUrl":"10.1016/j.jappgeo.2025.106066","url":null,"abstract":"<div><div>The evaluation of the gravity field induced by a finite mass distribution is an interdisciplinary research topic with a wide number of applications in geodesy, geophysics and astronomy. Starting from the equation of motion, modeling of the force component due to a given distribution is a challenging procedure. The scope of the paper is to review different methodologies available for this computation. The considered techniques examine both analytical and numerical evaluation of the corresponding integral expressions and include the polyhedral and prismatic modeling, surface and volume integral methods, series expansions and spherical harmonics, dynamic modeling of polyhedral shapes and gravity signal changes. In addition, three state-of-the-art applications related to potential field modeling are presented. Firstly, the computation of mutual potentials in the frame of studying the dynamics of binary mass systems and their interactions. Secondly, the stochastic representation of asteroid shape models in order to compute gravity signal variations implied by specific mass changes, an approach suited to model time variable gravity fields. Thirdly, the calculation of terrain corrections based on the evaluation of regional potential fields using Digital Terrain Model data.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"245 ","pages":"Article 106066"},"PeriodicalIF":2.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Failure laws of the backfill borehole surrounding rock under three-dimensional non-hydrostatic stress field: Insight into the first principal deviatoric stress and strain energy density","authors":"Chunkang Liu ,&nbsp;Hongjiang Wang ,&nbsp;Shuangcheng Du ,&nbsp;Yafei Zhai","doi":"10.1016/j.jappgeo.2025.106071","DOIUrl":"10.1016/j.jappgeo.2025.106071","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Effectively analyzing the failure risk in backfill borehole (BFB) is important in exploiting metal and coal resources in complex deep formations. The distribution laws of the first principal deviatoric stress (FPDS) field and strain energy density (SED) in BFB surrounding rock are analyzed theoretically. The analysis is conducted under a three-dimensional (3D) non-hydrostatic stress field to explore the failure laws of the surrounding rock. The correctness of theoretical results is verified by numerical simulation of plastic zone and engineering case. Results show that the FPDS field in the BFB surrounding rock varies obviously in different dominant stress fields. The maximum of FPDS occurs within the range of 55° to 65° under &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&gt;&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;V&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&gt;&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, and the field displays an ‘8’-shaped distribution, indicating a potential ‘8’-shaped failure zone. When &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;V&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&gt;&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&gt;&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; or &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&gt;&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&gt;&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;V&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, the maximum of FPDS appears in the direction parallel to &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; or &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, and the field presents either an ‘8’-shaped or elliptical distribution. Moreover, the distribution characteristics of SED partially reveal the failure pattern of the BFB, and the theoretical SED analysis results show good agreement with the numerical simulation of the BFB plastic zone, thereby confirming the theoretical accuracy. The SED parallel to the direction of &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; differs significantly in both magnitude and its variation with changes in &lt;em&gt;λ&lt;/em&gt;. Especially, under the conditions of equal &lt;em&gt;p&lt;/em&gt; and unequal &lt;em&gt;q&lt;/em&gt;, the SED decreases with &lt;em&gt;λ&lt;/em&gt; within the range of 0° to 15° in the &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; dominant stress field with &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;V&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&gt;&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, while which increases with &lt;em&gt;λ&lt;/em&gt; under other conditions. A case study of BFB in a copper mine mutually verifies the consistency the FPDS field and SED distribution of the surrounding rock. Furthermore, the minimum mud-wall pressure is calculated using a Lode angle function considering the third invariant of the deviatoric stress, bringing a 24.206 % reduction of the growth rate. By extending classical mechanics with 3D stress and energy considerations, the r","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"245 ","pages":"Article 106071"},"PeriodicalIF":2.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Induced polarization effects in transient electromagnetic data: A case study from the Hawiah volcanogenic massive sulfide deposit in Saudi Arabia","authors":"Hesham El-Kaliouby ,&nbsp;Juntao Lu ,&nbsp;Panagiotis Kirmizakis ,&nbsp;Abid Khogali ,&nbsp;Tim Eatwell ,&nbsp;Tomos Bryan ,&nbsp;Pantelis Soupios","doi":"10.1016/j.jappgeo.2025.106084","DOIUrl":"10.1016/j.jappgeo.2025.106084","url":null,"abstract":"<div><div>In exploring volcanogenic massive sulfide (VMS) deposits, the transient electromagnetic (TEM) method is highly effective due to its sensitivity to metallic conductors such as sulfide minerals. A recent TEM survey over the Hawiah VMS deposit in Saudi Arabia utilized ten stations to investigate the distribution of VMS targets. Several stations exhibited anomalous fast decay curves attributed to induced polarization (IP) effects, a common characteristic of VMS minerals. Spectral IP (SIP) measurements of local VMS core samples indicated large IP effects, aligning with results from a previous time domain IP (TDIP) survey in the area. IP effects can distort TEM measurements, causing as fast decay followed by sign reversals, complicating interpretation when using conventional resistivity-only (RO) workflows. These distortions can result in unreliable interpretations, especially in regions with complex subsurface conditions. In this paper, we present a synthetic model analysis based on geological setting information, demonstrating that in scenarios with moderately resistive backgrounds and deeply buried high-polarizable bodies, TEM curves can exhibit anomalous fast decay in the middle to late time, aligning with the observed field data. Thus, this behavior serves as a key indicator of IP effects in the survey area. Through RO and IP-incorporated inversions, along with an uncertainty analysis of the resulting resistivity models, our findings show that the data is better fitted using an IP-incorporated inversion approach. This highlights the importance of analyzing anomalous decay in TEM data and supports adopting refined methodologies that account for IP effects. Such approaches are crucial for achieving accurate and reliable evaluations in areas with highly conductive and polarizable materials, like VMS deposits.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"245 ","pages":"Article 106084"},"PeriodicalIF":2.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Error calibration for cross-shaped magnetic gradient tensor system based on the improved differential evolution algorithm","authors":"Chenxu Dong,&nbsp;Zhuoxuan Li,&nbsp;Yuguo Li,&nbsp;Xuezhen Ding","doi":"10.1016/j.jappgeo.2025.106080","DOIUrl":"10.1016/j.jappgeo.2025.106080","url":null,"abstract":"<div><div>Errors arising from sensor manufacturing and misalignment during installation have been shown to have a significant impact on the measurement accuracy of magnetic gradient tensor systems. This, in turn, can result in a reduction in detection performance in practical applications such as magnetic anomaly detection. This study proposes a high-precision error calibration method for a cross-shaped magnetic gradient tensor system. This method uses the Success-History based Adaptive Differential Evolution with Linear Population Size Reduction (L-SHADE) algorithm, an enhanced variant of the Differential Evolution (DE) algorithm, to estimate these error parameters. A unified optimization model has been developed that incorporates multiple sensor errors into a single calibration framework, thereby enabling one-step error correction. Simulation experiments are conducted under both conditions of absence of noise and conditions of presence of noise. In conditions of absence of noise, the discrepancy between the calibrated and theoretical total magnetic field is of the order of <span><math><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup></math></span> nT, with all magnetic gradient tensor components and invariants tending toward zero. In field experiments, the maximum deviation between the calibrated total magnetic field and the actual geomagnetic field is 1.92 nT, and the maximum improvement ratio of tensor components reaches 979. The findings from both simulation and field trials have been shown to demonstrate that the proposed algorithm successfully attains high calibration accuracy and computational efficiency, thus providing a pragmatic approach for sensor error correction.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"245 ","pages":"Article 106080"},"PeriodicalIF":2.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ME-YOLO: A novel real-time detection network for pavement interlayer distress using ground-penetrating radar","authors":"Senguo Cao ,&nbsp;Congde Lu ,&nbsp;Xiao Wang ,&nbsp;Peng Zhang ,&nbsp;Guanglai Jin ,&nbsp;Wenlong Cai","doi":"10.1016/j.jappgeo.2025.106057","DOIUrl":"10.1016/j.jappgeo.2025.106057","url":null,"abstract":"<div><div>Interlayer distress detection in asphalt pavement is critical for highway maintenance, as timely identification of pavement distress can ensure operational safety, reliability, and extended service life. However, the problems of feature information loss and the substantial confusable backgrounds significantly hinder detection accuracy. To address these limitations, we propose an enhanced network specifically designed for automated interlayer distress detection named ME-YOLO. Firstly, we design a Multiscale Adaptive Feature Fusion (MAFF) module, which aggregates more scale information by Adaptive Spatial Feature Fusion (ASFF). This design links all feature scales to make discriminative features in each scale propagate directly to subsequent modules, enriching semantic representations and mitigating the risk of feature loss, while leveraging shallow-layer features to strengthen spatial localization. Furthermore, the Efficient Partial Self-Attention (EPSA) module is introduced to suppress background interference in complex environments. Unlike conventional transformers, EPSA adopts partial self-attention operations with multi-path fusion, which can enable the network to acquire global representation capability with low computational overhead. Extensive experiments indicate that the ME-YOLO network outperforms the given state-of-the-art models, including Faster-RCNN, RT-DETR, YOLOv8s, and YOLOv11s, on the interlayer distress dataset. Compared to YOLOv5s, ME-YOLO achieves improvements of 2.2% in mAP_0.5 and 3.5% in mAP_0.5:0.95, while maintaining an inference speed of 6.7 ms per image. The source code will be available at <span><span>https://github.com/caosenguo/ME-YOLO</span><svg><path></path></svg></span>.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"245 ","pages":"Article 106057"},"PeriodicalIF":2.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated fault interpretation from gravity and magnetic data in covered areas using machine learning: A case study of the Eastern Tianshan orogenic belt","authors":"Huaqing Yang ,&nbsp;Fan Xiao ,&nbsp;Hao Jia ,&nbsp;Yongzhang Zhou ,&nbsp;Shu Jiang","doi":"10.1016/j.jappgeo.2025.106040","DOIUrl":"10.1016/j.jappgeo.2025.106040","url":null,"abstract":"<div><div>Machine learning has emerged as a powerful tool for integrating multi-source geophysical data, such as gravity and magnetic measurements, to enhance geological mapping. The Eastern Tianshan region, characterized by its Gobi-desert landscape, poses significant challenges for understanding regional structures, thereby complicating geological mapping and exploration targeting. To address these challenges, this study employs machine learning methods to fuse gravity and magnetic data for automated fault interpretation. Predictor maps were generated by applying a suite of boundary enhancement techniques, including the total horizontal derivative, vertical derivative, tilt angle, analytic signal, theta map, total horizontal derivative tilt angle, horizontal tilt angle, enhanced analytic signal tilt angle, and enhanced tilt angle methods, to aerial gravity and magnetic data. Two machine learning algorithms, namely Random Forest (RF) and Deep Neural Networks (DNNs), were then applied to these predictor maps to automatically identify the spatial distribution of concealed faults beneath the Gobi-desert covered layer. The grid search method was used to optimize the parameter combinations for both models. The results indicate that the RF model achieved an average accuracy of 86.20 %, outperforming the DNNs model, which achieved an average accuracy of 78.22 %. Based on this comparative analysis, the RF model was selected for fault interpretation in the Eastern Tianshan region. This approach provides critical data-driven insights into the spatial distribution of concealed faults, offering valuable guidance for subsequent geological mapping and exploration efforts.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"245 ","pages":"Article 106040"},"PeriodicalIF":2.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145625386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ductile-brittle failure transition of rocks subjected to temperature heating and water cooling in process of drilling with high confining pressure","authors":"Jing Wang,&nbsp;Mingming He,&nbsp;Haoteng Wang,&nbsp;Faning Dang","doi":"10.1016/j.jappgeo.2025.106037","DOIUrl":"10.1016/j.jappgeo.2025.106037","url":null,"abstract":"<div><div>Thermal stress and cooling shock play a critical role in the drilling geothermal exploitation. To enhance drilling efficiency, cooling fluids are typically employed to reduce the temperature of the bit. In this study, digital drilling, compression tests and acoustic emission tests were conducted on rocks subjected to high-temperature heating and water cooling with varying confining pressures. A theoretical model of ductile-brittle failure transition of rock was established considering the friction effect and confining pressure during drilling. The evolution mechanism of drilling parameters and failure modes of rocks was investigated under the influence of thermal shock during the drilling process with varying confining pressure. The results show that with the gradual increase in cutting depth, rock exhibits a transition from ductile to brittle failure subjected to thermal shock. Thrust force, cutting force, mechanical specific energy (MSE), cutting depth and acoustic emission ringing counts all show a positive correlation with the increase of confining pressure. However, thrust force, cutting force and the critical cutting depth for the transition of failure modes are significantly reduced for rocks subjected to thermal shock during the drilling process. This suggests that the thermal shock weakens rock's mechanical properties and alters its failure mode. The study proposes an efficient and precise method for identifying the critical point of failure mode transition in rocks treated with thermal shock during high confining pressure drilling. This method offers a new perspective for understanding the behavior of rock break in complex thermal-mechanical- hydraulic coupled environments.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"245 ","pages":"Article 106037"},"PeriodicalIF":2.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145625390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}