Near Surface Geophysics最新文献

High‐resolution surface‐wave‐constrained mapping of sparse dynamic cone penetrometer tests 稀疏动态圆锥贯入仪测试的高分辨率地表波约束绘图

IF 1.6 4区地球科学

Near Surface Geophysics Pub Date : 2024-09-18 DOI: 10.1002/nsg.12321

Ao Wang, Fayçal Rejiba, Ludovic Bodet, Cécile Finco, Cyrille Fauchard

{"title":"High‐resolution surface‐wave‐constrained mapping of sparse dynamic cone penetrometer tests","authors":"Ao Wang, Fayçal Rejiba, Ludovic Bodet, Cécile Finco, Cyrille Fauchard","doi":"10.1002/nsg.12321","DOIUrl":"https://doi.org/10.1002/nsg.12321","url":null,"abstract":"The dynamic cone penetrometer (DCP) provides local soil resistance information. The difference in the vertical and horizontal data resolution (centimetric vs. multi‐metric) makes it difficult to spatialize the DCP data directly. This study uses a high‐resolution section, extracted by the seismic surface‐wave method, as the auxiliary and physical constraint for mapping the DCP index (DCPI). Geostatistical formalism (kriging and cokriging) is used. The associated measurement error of the seismic surface‐wave data is also included in the cokriging system, that is, the cokriging with variance of measurement error (CKVME). The proposed methods are validated for the first time on a test site designed and constructed for this study, with known geotechnical perspectives. Seismic and high‐intensity DCP campaigns were performed on the test site. The results show that with decimating the number of DCP soundings, the kriging approach is no longer capable of estimating the lateral variation in the test site, and the root‐mean‐square error (RMSE) value of the kriging section is increased by . With the help of sections constraining the lateral variability model, the RMSE values of the cokriging and the CKVME sections are increased by and .","PeriodicalId":49771,"journal":{"name":"Near Surface Geophysics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142264726","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}

引用次数: 0

Application of iterative elastic reverse time migration to shear horizontal ultrasonic echo data obtained at a concrete step specimen 将迭代弹性反向时间迁移应用于在混凝土台阶试件上获得的剪切水平超声回波数据

IF 1.6 4区地球科学

Near Surface Geophysics Pub Date : 2024-08-12 DOI: 10.1002/nsg.12318

Maria Grohmann, Ernst Niederleithinger, Christoph Büttner, Stefan Buske

{"title":"Application of iterative elastic reverse time migration to shear horizontal ultrasonic echo data obtained at a concrete step specimen","authors":"Maria Grohmann, Ernst Niederleithinger, Christoph Büttner, Stefan Buske","doi":"10.1002/nsg.12318","DOIUrl":"https://doi.org/10.1002/nsg.12318","url":null,"abstract":"The ultrasonic echo technique is broadly applied in non‐destructive testing (NDT) of concrete structures involving tasks such as measuring thickness, determining geometry and locating built‐in elements. To address the challenge of enhancing ultrasonic imaging for complex concrete constructions, we adapted a seismic imaging algorithm – reverse time migration (RTM) – for NDT in civil engineering. Unlike the traditionally applied synthetic aperture focusing technique (SAFT), RTM takes into account the full wavefield including primary and reflected arrivals as well as multiples. This capability enables RTM to effectively handle all wave phenomena, unlimited by changes in velocity and reflector inclinations. This paper concentrates on applying and evaluating a two‐dimensional elastic RTM algorithm that specifically addresses horizontally polarized shear (SH) waves only, as these are predominantly used in ultrasonic NDT of concrete structures. The elastic SH RTM algorithm was deployed for imaging real ultrasonic echo SH‐wave data obtained at a concrete specimen exhibiting a complex back wall geometry and containing four tendon ducts. As these features are frequently encountered in practical NDT scenarios, their precise imaging holds significant importance. By applying the elastic SH RTM algorithm, we successfully reproduced nearly all reflectors within the concrete specimen. In particular, we were capable of accurately reconstructing all vertically oriented reflectors as well as the circular cross sections of three tendon ducts, which was not achievable with traditional SAFT imaging. These findings demonstrate that elastic SH RTM holds the ability to considerably improve the imaging of complex concrete geometries, marking a crucial advancement for accurate, high‐quality ultrasonic NDT in civil engineering.","PeriodicalId":49771,"journal":{"name":"Near Surface Geophysics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939426","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}

引用次数: 0

Innovative imaging of iron deposits using cross‐gradient joint inversion of potential field data with petrophysical correlation 利用电位场数据的跨梯度联合反演和岩石物理相关性对铁矿床进行创新成像

IF 1.1 4区地球科学

Near Surface Geophysics Pub Date : 2024-08-08 DOI: 10.1002/nsg.12317

Bardiya Sadraeifar, Maysam Abedi

{"title":"Innovative imaging of iron deposits using cross‐gradient joint inversion of potential field data with petrophysical correlation","authors":"Bardiya Sadraeifar, Maysam Abedi","doi":"10.1002/nsg.12317","DOIUrl":"https://doi.org/10.1002/nsg.12317","url":null,"abstract":"This study demonstrates the application of the cross‐gradient joint inversion method to investigate iron mineralization zones within a volcano‐sedimentary environment. The presence of minerals with intense contrasts in density or magnetic susceptibility, such as hematite or magnetite, facilitates modelling the distribution of ore bodies with depth. Our approach involves establishing a unified interpretation of reconstructed density and susceptibility models through both independent and joint inversion with sparsity regularization in conjunction with a petrophysical model resulting from core data. This approach provides an ideal strategy to uncover the realistic geologic setting of iron ore deposits. We initially simulated a synthetic model closely resembling real‐case scenarios to assess the efficacy of the cross‐gradient joint inversion algorithm in comparison to independent inversion. Subsequently, the inversion algorithms were implemented on gravity and magnetic data, collected over an area of 500 × 600 m2 in Shavaz iron‐bearing deposits located in the central Iranian block. The primary iron oxide–apatite type mineralization in the study area is associated with the Nain–Dehshir–Baft fault as a NW–SE trending strike‐slip fault. Although both inversion methods yield satisfactory models, incorporating the cross‐gradient constraint in joint inversion resulted in a more constrained delineation of iron–oxide ore deposits in the fault system. This improvement facilitates the differentiation between hematite and a small percentage of magnetite, providing a more accurate estimation of ore depth. Inversion results suggest that the magnetite mineralization is coated with extensive hematite mineralization and both are positioned relatively within the same depth interval, covered by approximately a 15–25 m sequence of sediments.","PeriodicalId":49771,"journal":{"name":"Near Surface Geophysics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141928025","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}

引用次数: 0

A fine‐tuning workflow for automatic first‐break picking with deep learning 利用深度学习对自动初选进行微调的工作流程

IF 1.6 4区地球科学

Near Surface Geophysics Pub Date : 2024-08-02 DOI: 10.1002/nsg.12316

Amir Mardan, Martin Blouin, Gabriel Fabien‐Ouellet, Bernard Giroux, Christophe Vergniault, Jeremy Gendreau

{"title":"A fine‐tuning workflow for automatic first‐break picking with deep learning","authors":"Amir Mardan, Martin Blouin, Gabriel Fabien‐Ouellet, Bernard Giroux, Christophe Vergniault, Jeremy Gendreau","doi":"10.1002/nsg.12316","DOIUrl":"https://doi.org/10.1002/nsg.12316","url":null,"abstract":"First‐break picking is an essential step in seismic data processing. For reliable results, first arrivals should be picked by an expert. This is a time‐consuming procedure and subjective to a certain degree, leading to different results for different operators. In this study, we have used a U‐Net architecture with residual blocks to perform automatic first‐break picking based on deep learning. Focusing on the effects of weight initialization on first‐break picking, we conduct this research by using the weights of a pre‐trained network that is used for object detection on the ImageNet dataset. The efficiency of the proposed method is tested on two real datasets. For both datasets, we pick manually the first breaks for less than 10 of the seismic shots. The pre‐trained network is fine‐tuned on the picked shots, and the rest of the shots are automatically picked by the neural network. It is shown that this strategy allows to reduce the size of the training set, requiring fine‐tuning with only a few picked shots per survey. Using random weights and more training epochs can lead to a lower training loss, but such a strategy leads to overfitting as the test error is higher than the one of the pre‐trained network. We also assess the possibility of using a general dataset by training a network with data from three different projects that are acquired with different equipment and at different locations. This study shows that if the general dataset is created carefully it can lead to more accurate first‐break picking; otherwise, the general dataset can decrease the accuracy. Focusing on near‐surface geophysics, we perform traveltime tomography and compare the inverted velocity models based on different first‐break picking methodologies. The results of the inversion show that the first breaks obtained by the pre‐trained network lead to a velocity model that is closer to the one obtained from the inversion of expert‐picked first breaks.","PeriodicalId":49771,"journal":{"name":"Near Surface Geophysics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141883143","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}

引用次数: 0

How to promote geophysics as a standard tool for geotechnical investigations 如何促进地球物理学成为岩土工程勘察的标准工具

IF 1.6 4区地球科学

Near Surface Geophysics Pub Date : 2024-06-15 DOI: 10.1002/nsg.12313

J. Gustafsson, H. Higgs

引用次数: 0

Integration of ground geophysical methods to characterize near‐surface aquifer zones within an active mine 整合地面地球物理方法，确定在役矿井内近地表含水层区的特征

IF 1.6 4区地球科学

Near Surface Geophysics Pub Date : 2024-06-14 DOI: 10.1002/nsg.12314

S. Gomo, N. Mutshafa, J. Dildar, M. Manzi, J. Bourdeau, B. Brodic, I. James, G. R. J. Cooper, R.J. Durrheim

{"title":"Integration of ground geophysical methods to characterize near‐surface aquifer zones within an active mine","authors":"S. Gomo, N. Mutshafa, J. Dildar, M. Manzi, J. Bourdeau, B. Brodic, I. James, G. R. J. Cooper, R.J. Durrheim","doi":"10.1002/nsg.12314","DOIUrl":"https://doi.org/10.1002/nsg.12314","url":null,"abstract":"Understanding near‐surface groundwater storage, flow patterns, surface and groundwater interactions in mining areas can assist in making mining more efficient and profitable. This is especially important in opencast mines affected by water inflows that may negatively affect production and increase mining costs. We map and characterize the near‐surface aquifer zones at the opencast site of Tharisa Minerals, located in the southwestern region of the Bushveld Complex (South Africa). The main goal is to infer pit water inflow at the mine site and determine how it may be better controlled. The Bushveld Complex hosts partially connected and unconfined alluvial, shallow‐weathered and crystalline bedrock aquifers, which are often connected by small‐scale permeable zones. Seismic refraction tomography, multichannel analysis of surface waves, electrical resistivity tomography and borehole data are used to map and understand the different aquifer zones in the vicinity of the mine, as well as infer their relation to water inflow in the mine pits. The geophysical surveys map the overburden, weathered bedrock aquifer zone, and the top of the crystalline aquifer rock zone reasonably well. They reveal extensive and deep weathering, and possible high hydraulic conductivity in the vicinity of the mine. The results provide a better understanding of the mine's near‐surface environment, which could be used to implement effective and targeted dewatering techniques, thus enabling better pit inflow water control to improve mine working conditions and production.","PeriodicalId":49771,"journal":{"name":"Near Surface Geophysics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141345004","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}

引用次数: 0

Research and application of Rayleigh wave imaging based on the Born–Jordan time‐frequency distribution 基于 Born-Jordan 时频分布的瑞利波成像研究与应用

IF 1.6 4区地球科学

Near Surface Geophysics Pub Date : 2024-06-03 DOI: 10.1002/nsg.12304

Xiang Min, Zhang Xuhui, Xiaoyong Yao, Zhongxiang Jiang

{"title":"Research and application of Rayleigh wave imaging based on the Born–Jordan time‐frequency distribution","authors":"Xiang Min, Zhang Xuhui, Xiaoyong Yao, Zhongxiang Jiang","doi":"10.1002/nsg.12304","DOIUrl":"https://doi.org/10.1002/nsg.12304","url":null,"abstract":"Currently, the horizontal resolution of Rayleigh wave exploration is low. In this study, we propose the Born–Jordan time‐frequency distribution to analyse Rayleigh waves. The seismic signal was filtered with a wavelet transform for denoising, and the Rayleigh wave was separated in the time domain. Using the Born–Jordan time‐frequency distribution, the time waveform of each frequency comprising the Rayleigh wave from every seismic channel was obtained, and the time difference of the Rayleigh wave with the same frequency was calculated, based on which the dispersion curve between the two channels was obtained. Combined with the multichannel Rayleigh wave dispersion curve, phase velocity and frequency imaging under the seismic arrangement were obtained. Applying this method to detect abnormal geological bodies in engineering investigations showed that hard geologic bodies, such as comcrete rocks, have high velocity and frequency, whereas weak ones have low velocity and frequency. This strategy facilitated the detection of fractured zones, underground goafs and obstacles during pipe‐jacking construction near the surface.","PeriodicalId":49771,"journal":{"name":"Near Surface Geophysics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141272958","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}

引用次数: 0

A collocated inversion of sources and early arrival waveforms for credible tomograms: Synthetic and field data examples 对可信层析成像的源波形和早期到达波形进行同位反演：合成和现场数据实例

IF 1.6 4区地球科学

Near Surface Geophysics Pub Date : 2024-06-03 DOI: 10.1002/nsg.12312

Han Yu, Jing Li, Sherif Hanafy, Lulu Liu

{"title":"A collocated inversion of sources and early arrival waveforms for credible tomograms: Synthetic and field data examples","authors":"Han Yu, Jing Li, Sherif Hanafy, Lulu Liu","doi":"10.1002/nsg.12312","DOIUrl":"https://doi.org/10.1002/nsg.12312","url":null,"abstract":"Waveform inversion is theoretically a powerful tool to reconstruct subsurface structures, but a usually encountered problem is that accurate sources are very rare, causing the computation to be unstable or divergent. This challenging practical problem, although sometimes ignored and even imperceptible, can easily create discrepancies in calculated shot gathers, which will then lead to wrong residuals that will be smeared back to the gradients, hence jeopardizing the inverted tomograms. For any real dataset, every shot gather corresponds to its unique source even if some gathers can be transformed alike after data processing. To resolve this problem, we propose a collocated inversion of sources and early arrival waveforms with the two submodules executing successively. Not only can this method reconstruct a decent source wavelet that approaches the ground truth, but also it can produce credible background tomograms with optimized sources. Part of the cycle skipping problems can also be mitigated because it avoids the trial and error experiments on various sources. Numerical tests on a synthetic and a land dataset validate the effectiveness of this method. Restrictions on initial sources or starting velocity models will be relaxed, and this method can be extended to any other applications for engineering or exploration purposes.","PeriodicalId":49771,"journal":{"name":"Near Surface Geophysics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141269557","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}

引用次数: 0

Experimental and numerical analysis of dielectric polarization effects in near‐surface earth materials in the 100 Hz–10 MHz frequency range: First interpretation paths 对 100 Hz-10 MHz 频率范围内近表面地球材料中的介电极化效应进行实验和数值分析：首次解释路径

IF 1.6 4区地球科学

Near Surface Geophysics Pub Date : 2024-05-27 DOI: 10.1002/nsg.12302

A. Tabbagh, B. Souffaché, D. Jougnot, A. Maineult, F. Rejiba, P. M. Adler, C. Schamper, J. Thiesson, C. Finco, A. Mendieta, F. Rembert, R. Guérin, C. Camerlynck

{"title":"Experimental and numerical analysis of dielectric polarization effects in near‐surface earth materials in the 100 Hz–10 MHz frequency range: First interpretation paths","authors":"A. Tabbagh, B. Souffaché, D. Jougnot, A. Maineult, F. Rejiba, P. M. Adler, C. Schamper, J. Thiesson, C. Finco, A. Mendieta, F. Rembert, R. Guérin, C. Camerlynck","doi":"10.1002/nsg.12302","DOIUrl":"https://doi.org/10.1002/nsg.12302","url":null,"abstract":"SummaryThe recent developments of electromagnetic induction and electrostatic prospection devices dedicated to critical zone surveys in both rural and urban contexts necessitate improving the interpretation of electrical properties through complementary laboratory studies. In a first interpretation step, the various experimental results obtained in the 100 Hz–10 MHz frequency range can be empirically fitted by a simple six‐term formula. It allows the reproduction of the logarithmic decrease of the real component of the effective relative permittivity and its corresponding imaginary component, the part associated with the direct current conductivity, one Cole–Cole relaxation and the real and imaginary components of the high‐frequency relative permittivity. For elucidating physical phenomena contributing to both the logarithmic decrease and the observed Cole–Cole relaxation, we first consider the Maxwell–Wagner–Sillars polarization. Using the method of moments, we establish that this continuous medium approach can reproduce a large range of relaxation characteristics. At the microscopic scale, the possible role of the rotation of the water molecules bound to solid grains is then investigated. In this case, contrary to the Maxwell–Wagner–Sillars approach, the relaxation parameters do not depend on the external medium properties.","PeriodicalId":49771,"journal":{"name":"Near Surface Geophysics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141168585","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}

引用次数: 0

Novel approaches of borehole‐GPR data processing and visualization – application for unexploded ordnance detection 钻孔 GPR 数据处理和可视化的新方法--应用于未爆弹药探测

IF 1.6 4区地球科学

Near Surface Geophysics Pub Date : 2024-05-20 DOI: 10.1002/nsg.12303

André Bredeck, Volkmar Schmidt, J.-P. Schmoldt

{"title":"Novel approaches of borehole‐GPR data processing and visualization – application for unexploded ordnance detection","authors":"André Bredeck, Volkmar Schmidt, J.-P. Schmoldt","doi":"10.1002/nsg.12303","DOIUrl":"https://doi.org/10.1002/nsg.12303","url":null,"abstract":"Borehole ground‐penetrating radar (BGPR) measurements allow for the detection of objects and structures in the subsurface and are often applied to the detection of unexploded ordnance (UXO). If omnidirectional borehole antennas in reflection mode are used for the measurement, the localization of UXO is only possible if the data from a multitude of boreholes are analysed. Data analysis is usually still done by manual picking of reflections. We propose novel approaches to process and visualize data from BGPR measurements in a more advanced and appealing manner. Therein, the reflected energy recorded in the radargrams is projected back to all potential reflection points in the three‐dimensional space around the boreholes. If the projection direction is considered, we obtain a vectorized energy projection image. Superposition of projected energy yields an easy‐to‐grasp indicator of possible locations of UXO and of regions of interest that ought to be investigated in more detail. These approaches have been applied to synthetic data and to data measured on a test site with buried UXO. The results show that energy projection is a useful tool for BGPR data visualization, although the result is dependent on data pre‐processing. The proposed methods provide novel representations of BGPR data based on an objective algorithm which will at least complement the conventional methods.","PeriodicalId":49771,"journal":{"name":"Near Surface Geophysics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141122375","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}

引用次数: 0