Geophysical Prospecting最新文献

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Constraining Contact-Depth Solutions Through the Enhanced Horizontal Gradient Amplitude 通过增强水平梯度振幅约束接触深度解
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-09-09 DOI: 10.1111/1365-2478.70078
Luan Thanh Pham, Saulo Pomponet Oliveira, Erdinc Oksum, Hanbing Ai, Fabiana de Fátima Giacomini
{"title":"Constraining Contact-Depth Solutions Through the Enhanced Horizontal Gradient Amplitude","authors":"Luan Thanh Pham,&nbsp;Saulo Pomponet Oliveira,&nbsp;Erdinc Oksum,&nbsp;Hanbing Ai,&nbsp;Fabiana de Fátima Giacomini","doi":"10.1111/1365-2478.70078","DOIUrl":"https://doi.org/10.1111/1365-2478.70078","url":null,"abstract":"<div>\u0000 \u0000 <p>Accurate depth estimation is crucial for the quantitative interpretation of magnetic anomalies, which plays a significant role in geological mapping, mineral exploration and subsurface investigations. Traditional depth estimation techniques, such as the contact-depth (CD) and tilt-depth (TD) methods, often suffer from the generation of spurious solutions, especially when applied to complex geological environments. To address this, we propose an enhanced depth estimation technique, namely, the located contact-depth (LCD) method that integrates the CD technique with the enhanced horizontal gradient amplitude (EHGA). By utilizing points near the peaks of EHGA, a mask is generated to constrain the solutions from the CD method, effectively eliminating false solutions. Furthermore, a stable finite-difference technique for calculating vertical derivatives is used to improve the robustness and stability of the outputs. The proposed technique is tested on synthetic data, both with and without noise, as well as on real aeromagnetic data from the Galinge Fe-polymetallic deposit (China). The results demonstrate that our method provides depth estimates with improved reliability and accuracy compared to traditional methods, reducing the number of spurious solutions and enhancing precision around source boundaries. The result from the real example is in good agreement with known structures, highlighting the potential for deep mineral exploration in the Galinge Fe-polymetallic deposit.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 7","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145022016","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}
引用次数: 0
A Simple Method for Estimating Shale Brittleness From Seismic Data: An Example From Offshore Norway 从地震资料估计页岩脆性的简单方法:以挪威近海为例
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-09-08 DOI: 10.1111/1365-2478.70076
Md. Jamilur Rahman, Owen Rohwer Huff, Sajjad Ahmadigoltapeh, Jan Inge Faleide, Manzar Fawad, Nazmul Haque Mondol
{"title":"A Simple Method for Estimating Shale Brittleness From Seismic Data: An Example From Offshore Norway","authors":"Md. Jamilur Rahman,&nbsp;Owen Rohwer Huff,&nbsp;Sajjad Ahmadigoltapeh,&nbsp;Jan Inge Faleide,&nbsp;Manzar Fawad,&nbsp;Nazmul Haque Mondol","doi":"10.1111/1365-2478.70076","DOIUrl":"https://doi.org/10.1111/1365-2478.70076","url":null,"abstract":"<div>\u0000 \u0000 <p>The brittleness of a caprock layer is an important property to measure, as it influences sealing integrity for subsurface fluid injection projects. However, brittleness is a complex function of various factors, such as mineral composition, diagenesis and effective stress, and consequently can vary spatially. Because well log-based methods for brittleness estimation are often spatially limited, we develop a simple workflow to estimate the brittleness of a shale formation directly from seismic data. The shale in question is the Draupne Formation of the Upper Jurassic age, which acts as a primary seal of Viking Group sandstones in the Horda Platform area of the northern North Sea for hydrocarbon extraction (e.g., the Troll field) and geological CO<sub>2</sub> storage (e.g., Smeaheia). First, well log data from 26 wells in the Horda Platform area is aggregated, focusing on the compressional sonic, bulk density and resistivity values of the Draupne Formation. This data are used to establish a linear model relating the acoustic impedance and elastic properties-estimated brittleness index (BI) of the Draupne Formation; these two quantities display a correlation of 0.86. By combining this acoustic impedance information with a wavelet extracted from field seismic data and using average acoustic properties for the relatively homogeneous underlying sandstone reservoir, synthetic seismograms corresponding to different BI values of the Draupne Formation are generated. The amplitudes extracted from the synthetic seismograms are then used to establish a quadratic model relating seismic amplitudes at the base Draupne reflection with the BI. Applying this quadratic model on a 2D seismic line from the Stord Basin (south of the Horda Platform) results in BI values that are close to elastic-properties-based values at wells which intersect the seismic line and an expected trend of increasing brittleness with respect to depth. This integrated method can be used as part of a workflow to characterize top seal effectiveness, which may be useful in fluid storage prospect evaluation.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 7","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145012255","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}
引用次数: 0
Image-Domain Least-Squares Migration Through Preconditioned Hessian 基于预条件Hessian的图像域最小二乘迁移
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-09-08 DOI: 10.1111/1365-2478.70071
Wei Zhang, Mauricio D. Sacchi
{"title":"Image-Domain Least-Squares Migration Through Preconditioned Hessian","authors":"Wei Zhang,&nbsp;Mauricio D. Sacchi","doi":"10.1111/1365-2478.70071","DOIUrl":"https://doi.org/10.1111/1365-2478.70071","url":null,"abstract":"<div>\u0000 \u0000 <p>Image-domain least-squares migration (IDLSM), which typically employs a diagonally dominant Hessian with narrow bandwidth for the inverse problem, provides an efficient deconvolution strategy for subsurface reflectivity imaging. Conventional methods often rely on the adjoint of the Born/Kirchhoff modelling operator to compute the Hessian matrix. However, the adjoint-derived Hessian is highly ill-conditioned, leading to slow convergence during linear inversion and resulting in images with undesired resolution and amplitude fidelity. To overcome these limitations, this study introduces a novel IDLSM approach that integrates the state-of-the-art migration operator. We derive and compute the preconditioned Hessian matrix through a Kirchhoff migration engine with source-side and receiver-side illumination. The preconditioned Hessian matrix exhibits identical values along its main diagonal. This illumination compensation will explicitly reduce the condition number of the Hessian matrix and significantly improve the quality of migrated images in terms of amplitude fidelity. In addition, we remove redundant source wavelets from the migrated image and the Hessian matrix. As a result, these improvements will greatly accelerate the convergence of linear inversion solvers while enhancing the resolution and amplitude fidelity of the resulting images. Experiments on synthetic and field datasets demonstrate that the proposed IDLSM method retrieves high-fidelity reflectivity images with superior resolution and amplitude fidelity compared to conventional IDLSM techniques.</p></div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 7","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145012344","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}
引用次数: 0
Case Study of Dual-Signal Processing of DAS-VSP Vibrator Data From a 3D Survey in a Geothermal Reservoir 某地热储层三维测量DAS-VSP振动器数据双信号处理实例研究
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-09-04 DOI: 10.1111/1365-2478.70073
Flavio Poletto, Cinzia Bellezza, Gualtiero Böhm, Fabio Meneghini, Athena Chalari, Anna Stork, Mahmut Parlaktuna, Erdinç Şentürk, Deyan Draganov, Gijs van Otten, Sevket Durucan
{"title":"Case Study of Dual-Signal Processing of DAS-VSP Vibrator Data From a 3D Survey in a Geothermal Reservoir","authors":"Flavio Poletto,&nbsp;Cinzia Bellezza,&nbsp;Gualtiero Böhm,&nbsp;Fabio Meneghini,&nbsp;Athena Chalari,&nbsp;Anna Stork,&nbsp;Mahmut Parlaktuna,&nbsp;Erdinç Şentürk,&nbsp;Deyan Draganov,&nbsp;Gijs van Otten,&nbsp;Sevket Durucan","doi":"10.1111/1365-2478.70073","DOIUrl":"https://doi.org/10.1111/1365-2478.70073","url":null,"abstract":"<p>The three-dimensional (3D) distributed acoustic sensing (DAS) vertical seismic profile (VSP) technique is an effective tool to characterize subsurface reservoirs, enabling the use of large and densely sampled borehole receiver arrays with many surface vibrator source points for onshore time-lapse monitoring. However, the processing of the DAS VSP signals for imaging purposes is based on a reliable wavefield separation, which may depend on the recognition and quality of the direct arrivals. To overcome this limitation for common-source gathers with poor signal-to- noise ratio or with interferences, we apply the dual-signal processing method, which allows us to estimate and separate the DAS wavefields by signals' combination without arrival picking. We present a case study of a 3D VSP DAS dataset recorded at a geothermal reservoir in Turkey, showing that the method, similar to a geophone and hydrophone combination, is robust and effective and can be advantageously integrated with the conventional processing. Supported by signal benchmarking, modelling and signal-to-noise ratio analysis, we treat common-source and common-receiver data. Our analysis shows the advantages and limitations of the proposed approach, valuable in the time-lapse perspective.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 7","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70073","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144998923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A 3D Joint Tomographic Inversion of First-Arrival and Reflection Waves Based On the Adjoint State Method 基于伴随状态法的初至波和反射波三维联合层析反演
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-09-03 DOI: 10.1111/1365-2478.70077
Junjie Sun, Huachen Yang, Fei Ma, Jianzhong Zhang
{"title":"A 3D Joint Tomographic Inversion of First-Arrival and Reflection Waves Based On the Adjoint State Method","authors":"Junjie Sun,&nbsp;Huachen Yang,&nbsp;Fei Ma,&nbsp;Jianzhong Zhang","doi":"10.1111/1365-2478.70077","DOIUrl":"https://doi.org/10.1111/1365-2478.70077","url":null,"abstract":"<div>\u0000 \u0000 <p>Seismic reflection traveltime tomography (RTT) is an effective technique for inverting subsurface low-frequency velocity models for prestack depth migration and full-waveform inversion of seismic data. However, the velocity model established using RTT demonstrates limited resolution for extremely shallow and deeply complex strata. Small-offset first-arrival wave effectively characterize velocity variations in shallow strata, whereas large-offset first-arrival wave can reflect the velocity distribution in deeper strata. Therefore, we propose a three-dimensional joint tomographic inversion of first-arrival and reflection waves based on the adjoint state method in this article. The method integrates first-arrival traveltime data, reflection traveltime data and slope data for inversion, enhancing the accuracy of the inversion model from shallow to deep. The adjoint state method is employed to calculate the gradient of the misfit function with respect to velocity and the spatial coordinates of reflection points, thereby reducing the computational memory requirements and improving the efficiency of velocity modelling. The results of synthetic data tests based on a theoretical model verify the accuracy and effectiveness of the proposed joint inversion method. The proposed method is applied to ocean bottom node and ocean bottom cable wide-line seismic data collected in an extremely shallow sea in eastern China, yielding a more accurate velocity model.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 7","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144935129","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}
引用次数: 0
Dynamic Streaming Potential Coupling Coefficient in Partially Saturated Porous Media 部分饱和多孔介质动态流势耦合系数
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-09-01 DOI: 10.1111/1365-2478.70072
Luong Duy Thanh, Santiago G. Solazzi, Nguyen Manh Hung, Nguyen Van Nghia, Phan Van Do, Damien Jougnot
{"title":"Dynamic Streaming Potential Coupling Coefficient in Partially Saturated Porous Media","authors":"Luong Duy Thanh,&nbsp;Santiago G. Solazzi,&nbsp;Nguyen Manh Hung,&nbsp;Nguyen Van Nghia,&nbsp;Phan Van Do,&nbsp;Damien Jougnot","doi":"10.1111/1365-2478.70072","DOIUrl":"https://doi.org/10.1111/1365-2478.70072","url":null,"abstract":"<div>\u0000 \u0000 <p>The seismoelectric effect is an electrokinetic phenomenon that arises when seismic waves propagate in water-containing geological formations. Given that seismoelectric signals are sensitive to the hydraulic properties of the probed porous medium, they have the capability to provide important information during subsurface characterization efforts. In this work, we present a physics-based model for the dynamic streaming potential coupling coefficient (SPCC) in partially saturated porous media. For this, we conceptualize the porous medium as a partially saturated bundle of capillary tubes. We take into account the variation of pore size to relate the capillary pressure to the water saturation in the porous medium of interest. We then up-scale the streaming current and conduction current within the saturated capillaries under oscillatory flow conditions from pore to sample scale. The results show that the dynamic SPCC is not only a function of water saturation and the probing frequencies but also of the properties of water, mineral–water interfaces and other microstructural parameters of the porous medium. We analyse and explain the characteristics of the dynamic SPCC for two different pore size distributions (PSD): fractal and lognormal. Results show that the PSD characteristics have a strong effect on the dynamic SPCC responses. The proposed model has a remarkable ability to replicate experimental data available in the literature. In addition, it is observed that the lognormal distribution can provide a better agreement with experimental data for sand samples, which display a relatively narrow PSD. The findings of this study provide a valuable basis for interpreting seismoelectric signals under partially saturated conditions. Our proposed technique can be applied to any PSD, regardless of the complexity, providing a flexibility that is not present in alternative models found in the literature.</p></div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 7","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144923624","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}
引用次数: 0
Seismic Imaging of the Southern Vienna Basin (Austria) Using Probabilistic Ambient-Noise Tomography 使用概率环境噪声层析成像的南维也纳盆地(奥地利)地震成像
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-09-01 DOI: 10.1111/1365-2478.70074
Clement Esteve, Y. Lu, J. M. Gosselin, R. Kramer, G. Bokelmann, G. Götzl
{"title":"Seismic Imaging of the Southern Vienna Basin (Austria) Using Probabilistic Ambient-Noise Tomography","authors":"Clement Esteve,&nbsp;Y. Lu,&nbsp;J. M. Gosselin,&nbsp;R. Kramer,&nbsp;G. Bokelmann,&nbsp;G. Götzl","doi":"10.1111/1365-2478.70074","DOIUrl":"https://doi.org/10.1111/1365-2478.70074","url":null,"abstract":"<p>Surface-wave ambient noise tomography has proven to be a cost-effective and reliable tool for imaging sedimentary basins when coupled with dense nodal seismic arrays. Here, we deployed 181 seismic nodes in two asynchronous phases across the southern Vienna Basin in spring 2024. We retrieve fundamental-mode Rayleigh and Love wave group velocity dispersion curves from seismic noise cross-correlations. We then obtained a pseudo three-dimensional (3D) <span></span><math>\u0000 <semantics>\u0000 <msub>\u0000 <mi>V</mi>\u0000 <msub>\u0000 <mi>S</mi>\u0000 <mi>V</mi>\u0000 </msub>\u0000 </msub>\u0000 <annotation>$V_{S_{V}}$</annotation>\u0000 </semantics></math> model and a seismic radial anisotropy (<span></span><math>\u0000 <semantics>\u0000 <mi>ζ</mi>\u0000 <annotation>$zeta$</annotation>\u0000 </semantics></math>) model of the area from a 2-step approach that employs trans-dimensional probabilistic (Bayesian) inference. The 3D <span></span><math>\u0000 <semantics>\u0000 <msub>\u0000 <mi>V</mi>\u0000 <msub>\u0000 <mi>S</mi>\u0000 <mi>V</mi>\u0000 </msub>\u0000 </msub>\u0000 <annotation>$V_{S_{V}}$</annotation>\u0000 </semantics></math> model highlights the structure of the Neogene basin. The 3D seismic radial anisotropy reveals several patterns, which may help constrain the presence and nature of faults and geologic fabrics in the study area. Combined, these models constrain first-order features of the basin structure that will be useful for planning further geothermal exploration. In particular, this work guides future detailed, spatially targeted two-dimensional/3D seismic reflection surveys.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 7","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70074","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144923625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
An Improved Bedrock Geology Characterization in Limerick Basin Using Multi-Geophysical Data Integration Guided by Petrophysics and Outcrop Data 以岩石物理和露头资料为指导的多物探数据整合改进Limerick盆地基岩地质特征
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-09-01 DOI: 10.1111/1365-2478.70066
Prithwijit Chakraborti, Aline Melo, Eoin Dunlevy, Mark Holdstock
{"title":"An Improved Bedrock Geology Characterization in Limerick Basin Using Multi-Geophysical Data Integration Guided by Petrophysics and Outcrop Data","authors":"Prithwijit Chakraborti,&nbsp;Aline Melo,&nbsp;Eoin Dunlevy,&nbsp;Mark Holdstock","doi":"10.1111/1365-2478.70066","DOIUrl":"https://doi.org/10.1111/1365-2478.70066","url":null,"abstract":"<p>Geological mapping in the Limerick Basin, Ireland, presents significant challenges due to the extensive glacial overburden obscuring the bedrock geology. To address this, multiple geophysical datasets comprising the Bouguer gravity anomaly, total magnetic intensity and resistivity depth slice at 60 m depth obtained from frequency domain electromagnetic data are integrated using a novel data integration workflow that uses geological (ground truth) and petrophysical data. The ground truth data available in this area contain information about the geological formations of outcrops and topmost geological units of drill cores procured from drilling campaigns undertaken by several mining companies.</p><p>The data integration workflow utilizes ground truth data for semi-supervised uniform manifold approximation and projection (UMAP) dimensionality reduction, which leads to cleaner separation of classes in the dimensionality-reduced data and improves the performance of the clustering algorithm for which we have used hierarchical density-based spatial clustering of applications with noise (HDBSCAN). The stochastic nature of UMAP yields slightly different results for each iteration. Hence, a repetitive workflow involving multiple iterations of UMAP and HDBSCAN is applied to create cluster maps with smoothly varying cluster labels, allowing us to classify them into ranges that are associated with geological formations and rock types using a combined interpretation technique involving geological, geophysical and petrophysical data.</p><p>The workflow is tested on a synthetic study inspired by the real geological setting of the Limerick Basin and geophysical datasets available in the area. The cluster map obtained from field data integration led to the proposal of a revised map of the area with significant modifications in the distribution of igneous and sedimentary units, specifically to the northwest and within the Limerick syncline region.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 7","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70066","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144923628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Data-Driven Pegmatite Exploration Targeting in a Geologically Underexplored Area in the Tysfjord Region, Norway 数据驱动的伟晶岩勘探目标位于挪威Tysfjord地区地质勘探不足的地区
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-08-26 DOI: 10.1111/1365-2478.70060
Hendrik Paasche, Marie-Andrée Dumais, Claudia Haase, Björn Eskil Larsen, Aziz Nasuti, Kerstin Saalmann, Georgios Tassis, Ying Wang, Axel Müller, Marco Brönner
{"title":"Data-Driven Pegmatite Exploration Targeting in a Geologically Underexplored Area in the Tysfjord Region, Norway","authors":"Hendrik Paasche,&nbsp;Marie-Andrée Dumais,&nbsp;Claudia Haase,&nbsp;Björn Eskil Larsen,&nbsp;Aziz Nasuti,&nbsp;Kerstin Saalmann,&nbsp;Georgios Tassis,&nbsp;Ying Wang,&nbsp;Axel Müller,&nbsp;Marco Brönner","doi":"10.1111/1365-2478.70060","DOIUrl":"https://doi.org/10.1111/1365-2478.70060","url":null,"abstract":"<p>We compute probabilistic Niobium–Yttrium–Fluorine (NYF) pegmatite prospectivity maps in the Tysfjord region in Northern Norway. NYF pegmatites are generally enriched in rare earth minerals and represent residual melts derived from granitic plutons or melts formed by partial melting of metaigneous rocks. In Tysfjord, however, these pegmatites contain high-purity quartz, which is the major target commodity of exploration and mining. As the area is geologically underexplored, we employ a data analytics approach for the discovery of new deposits. We carefully lay out our knowledge base and how it impacts the working hypothesis and feature engineering. Self-organizing maps are employed as an unsupervised and random forest classification as a supervised data analytics algorithm to process and link features derived from airborne magnetic and radiometric maps with sparse pegmatite occurrences available in the form of outcrops and active and abandoned mines. The predictive power of our probabilistic pegmatite prospectivity maps is analysed by means of additional boreholes, which indicates the usefulness of our prospectivity maps for exploration targeting. We recommend employing unsupervised and supervised data analytics approaches in exploration targeting case studies where uncertainty about the predictive power of the available database cannot be ruled out before subjecting the database to data analytics.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70060","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144897411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A Deep Learning Approach for Transient Electromagnetic Data Denoising, Inversion and Uncertainty Analysis With Monte Carlo Dropout Technique 基于蒙特卡罗Dropout技术的瞬变电磁数据去噪、反演和不确定性分析的深度学习方法
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-08-25 DOI: 10.1111/1365-2478.70069
Yinjia Zhu, Yeru Tang, Jianhui Li, Xiangyun Hu, Ronghua Peng
{"title":"A Deep Learning Approach for Transient Electromagnetic Data Denoising, Inversion and Uncertainty Analysis With Monte Carlo Dropout Technique","authors":"Yinjia Zhu,&nbsp;Yeru Tang,&nbsp;Jianhui Li,&nbsp;Xiangyun Hu,&nbsp;Ronghua Peng","doi":"10.1111/1365-2478.70069","DOIUrl":"https://doi.org/10.1111/1365-2478.70069","url":null,"abstract":"<div>\u0000 \u0000 <p>A comprehensive deep learning approach was introduced, encompassing data denoising, inversion imaging and uncertainty analysis. For denoising transient electromagnetic (TEM) data, we utilized a Bidirectional Long Short-Term Memory (BiLSTM) network. In the data inversion process, a combination of convolutional neural network (CNN) and BiLSTM structures was employed, and their outputs were consolidated using a multi-head attention mechanism. To ensure robust performance under challenging noise conditions, we implemented a specialized multi-channel noise training protocol during model optimization. The framework incorporates Monte Carlo (MC) dropout techniques to systematically evaluate prediction reliability throughout the inversion pipeline. This approach has not only been validated on test datasets but has also been successfully applied to the field dataset collected at the Narenbaolige Coalfield in Inner Mongolia, China. The deep learning inversion results obtained from both raw and denoised data exhibit reduced vertical continuity and increased roughness characteristics. In contrast, the Occam's inversion method with smoothness constraints yields results demonstrating superior lateral continuity and vertical smoothness. It is noteworthy that both inversion approaches show consistent interpretations regarding the scale of basalt formations and their contact interfaces with underlying sedimentary layers. Further uncertainty analysis reveals relatively higher uncertainty characteristics in the transition zones between basalt and sedimentary layers, as well as in deeper formations. The elevated uncertainty at interface regions may be attributed to model resolution limitations and inversion ill-posedness issues, whereas the higher uncertainty in deeper formations is more likely caused by the volumetric effects of electromagnetic field detection and the influence of observational data noise.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894274","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}
引用次数: 0
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