Journal of Applied Geophysics最新文献

{"title":"Study on the site effects of trapezoidal sedimentary valleys under oblique incidence of SH waves based on the IBIEM","authors":"Xiangjiang Li,&nbsp;Zhiqiang Song,&nbsp;Leichao Zhao,&nbsp;Chuang Li,&nbsp;Yunhe Liu","doi":"10.1016/j.jappgeo.2024.105609","DOIUrl":"10.1016/j.jappgeo.2024.105609","url":null,"abstract":"<div><div>Trapezoidal sedimentary valley sites exhibit significant differences in ground motion characteristics and a nonuniform distribution pattern under the oblique incidence of seismic waves. On the basis of the indirect boundary integral equation method (IBIEM), the scattered field of a sedimentary valley site is obtained by constructing and solving the Green's function of the scattering wave source from the valley sedimentary layer. This paper systematically and parametrically investigates the seismic ground motion characteristics and nonuniform distribution patterns of sedimentary valleys as they vary with changes in valley topographic parameters, oblique incidence angles of SH waves, and impedance ratios between bedrock and sedimentary layers. This study analyzed the differences between considering the scattering effects of sedimentary valleys and accounting only for the free-field seismic motion at the truncated boundary of the foundation. On the basis of this analysis, a more rational approach for ground motion input was proposed. The results indicate that as the valley height increases or the bottom width decreases, the sedimentary valley transitions from exhibiting edge effects to focusing effects. The oblique incidence of seismic waves significantly increases the amplification and nonuniformity of the peak displacements on the surface of the sedimentary valleys, with the maximum peak reaching more than five times the peak displacement of the incident wave. The change in slope has a significant effect on the seismic response at the inner and outer surfaces of the wedge. This phenomenon has been explained for the first time through ray theory. The amplification effect of sedimentary valley displacement becomes more pronounced with increasing impedance ratio. Compared with the free field on flat bedrock, the scattering effects generated by hollow and sedimentary valleys have a significant effect on the ground motion field at the truncated boundaries. The maximum errors at the bottom and right boundaries can reach 30.8 % and 54.8 %, respectively. Therefore, the total field that considers scattering effects should be used as the ground motion input.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"233 ","pages":"Article 105609"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143096568","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":"Effects of a 3D basin on the near-fault ground motion by an FK-FE hybrid method","authors":"Zhenning Ba ,&nbsp;Shujuan Han ,&nbsp;Jingxuan Zhao ,&nbsp;Zhonghan Liu","doi":"10.1016/j.jappgeo.2024.105581","DOIUrl":"10.1016/j.jappgeo.2024.105581","url":null,"abstract":"<div><div>In the pursuit of accurately representing the full-process ground motion of a 3D near-fault complex site, an FK-FE hybrid method based on the idea of domain reduction is proposed. By integrating the Frequency-Wavenumber (FK) and Finite Element (FE) Methods, the hybrid method provides a new solution to seismic modeling which adaptively addresses multi-scale crustal models (from crustal to geotechnical scale) and intricate 3D site models, with consistent efficiency and precision. Then, the hybrid method is verified by comparing with results of the FK method and further validated by comparing with strong-earthquake records of the 2021 Yangbi M6.4 earthquake. Further, the proposed hybrid method is used to investigate the influence of the basin (wave velocity ratio of internal and external medium, basin's thickness) on near-fault effects due to the finite-fault source, and reveal the comprehensive mechanism of near-fault effects and basin effects. The results show that: the basin-focusing effect enhances the concentration of near-fault ground motions, and further expands the concentration range of strong-earthquake. The increases of the wave velocity ratio and basin's thickness augment the basin-focusing effect, and then the amplification effect of the basin on the fling-step effect becomes more pronounced. These results can provide a reference basis for seismic ground motion estimation and engineering seismic design in near-field complex sites.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"233 ","pages":"Article 105581"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143096569","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":"Tensor ratio small subdomain filtering technique for edge detection","authors":"Zhenhua Tai,&nbsp;Yuanhao Wang,&nbsp;Guohua Zhang,&nbsp;Xiangwen Li,&nbsp;Dezhi Huang","doi":"10.1016/j.jappgeo.2025.105635","DOIUrl":"10.1016/j.jappgeo.2025.105635","url":null,"abstract":"<div><div>Edge detection is an important processing method for potential field data, used to determine the horizontal location of the edges of causative sources. We proposed an edge detection filtering based on a gradient tensor ratio and improved the small subdomain filtering technique, and merged them into a tensor ratio small subdomain filtering technique. The proposed detection filter utilizes numerical differentiation and Laplace equation to compute gradient tensors. To weaken the interference of random noise on the small subdomain filtering and the irregular bending of contour lines in its result, we replace the original data at the center with a weighted average of the data within the window, where the weighting factors are determined by the distance of each data point to the center point and the standard deviation between equidistant data points. Final filtering output is the weighted average of the data within the subdomain that has the minimum standard deviation, wherein tighten gradient belts are utilized as indicators for detecting the edges of causative sources. Test results on synthetic data show that the proposed method has higher detection accuracy and stability compared to previous methods, and can enhance local anomalies. We also apply them to a real gravity data, and the obtain results indicate that the proposed method can effectively detect fault locations and highlight the residual density characteristics of causative sources.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"233 ","pages":"Article 105635"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143097100","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":"Progress of the pseudoseismic imaging technology for transient electromagnetic method","authors":"Junjie Xue ,&nbsp;Kerui Fan ,&nbsp;Xin Wu ,&nbsp;Wenhan Li ,&nbsp;Quanhui Guo","doi":"10.1016/j.jappgeo.2024.105600","DOIUrl":"10.1016/j.jappgeo.2024.105600","url":null,"abstract":"<div><div>The transient electromagnetic method (TEM) has been widely applied in metal mineral detection and engineering geology investigation. While mapping the resistivity distribution through the inversion of the TEM data, the subsurface structure of conductivity can be revealed by converting TEM data to the pseudo wavefield. The wavefield transform method is consequently an effective way to highlight the geoelectric structure. However, this field inversion belongs to a first-class Fredholm integral, which is a typical ill-posed problem. So, the key problem of wavefield transform is how to get a pseudo wavefield with proper resolution and stability. This paper first analyzes some traditional TEM imaging algorithms, including aspects such as time-frequency equivalent conversion, wavefield transform, and the Kirchhoff integral imaging and swept time transformation algorithms. Then, this paper concludes with some methods that can improve the inversion results resolution of wavefield transform. To obtain high-quality electromagnetic pseudo wavefield profiles, additional technical methods, such as Born approximation imaging, pulse spectrum inversion and full waveform inversion, are used in the inversion interpretation of electromagnetic field.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"233 ","pages":"Article 105600"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143096563","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":"Semi-supervised intelligent inversion from prestack seismic attributes guided by geophysical prior knowledge","authors":"Lei Zhu ,&nbsp;Fanchang Zhang ,&nbsp;Shunan Zhang ,&nbsp;Ji-an Wu","doi":"10.1016/j.jappgeo.2025.105620","DOIUrl":"10.1016/j.jappgeo.2025.105620","url":null,"abstract":"<div><div>Supervised deep learning methods currently used for prestack parameter prediction are suffered from the problem of limited training samples. The lack of clear physical meanings for deep learning models also makes prediction results unreliable. To address these issues, we proposed a geophysical prior knowledge guided semi-supervised (GPKGS) deep learning framework for amplitude-versus-angle (AVA) inversion. Based on prior physical knowledge, the prestack seismic data are decoupled into prestack seismic attribute data of the elastic parameters. Meanwhile, according to the prestack seismic attribute data, constructing the new forward models corresponding to each elastic parameter. The intelligent inversion framework is built based on the constructed forward models. This reduces the dependence of the framework on training data. This GPKGS framework preserves the physical procedure of AVA inversion, making intelligent inversion results reliable. The framework contains three branch networks for each elastic parameter. Each branch network contains an inversion neural network (INN) and a forward neural network (FNN). The INN can invert the prestack seismic attribute data into elastic parameters, which corresponding to inversion process. The FNN convert the obtained elastic parameters into synthetic prestack seismic attribute data, which corresponding to forward process. To ensure a reliable training process, the difference between the prestack seismic attribute data and the synthetic data are used to train the framework supervised by well log data. In addition, to obtain more stable results, at prediction stage, the prior information is introduced to help the FNN update the elastic parameters output by INN. The Marmousi2 model and a deep carbonate data are used to test the proposed framework. We find that the intelligent inversion results of the proposed network perform well at the situation of few training data.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"233 ","pages":"Article 105620"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092047","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":"Suppressing short time marine ambient noise based on deep complex unet to enhance the vessel radiation signal in LOFAR spectrogram","authors":"Yuzhe Wang ,&nbsp;Shijie Qiu ,&nbsp;Guoqing Hu ,&nbsp;Bin Wu ,&nbsp;Yi Yu","doi":"10.1016/j.jappgeo.2024.105611","DOIUrl":"10.1016/j.jappgeo.2024.105611","url":null,"abstract":"<div><div>UNet-type networks have demonstrated good performance in the field of denoising. In this paper, we applied a DCUNet network specifically for denoising underwater acoustic signals, which are characterized by their nonlinear, non-smooth and non-Gaussian features. The process involves transforming noisy data into LOFAR spectrograms for input into DCUnet, redesigning the network structure based on the features of underwater acoustic signals. Subsequently, a Noise2Noise training method was employed to reconstruct the underwater background noise through the end-to-end architecture. The effectiveness of the algorithm was validated on publicly available datasets after augmentation. Extensive experimental results show that our method achieves an SNR improvement of over 10 dB and is capable of restoring signals with an initial SNR of −20 dB, demonstrating better performance compared to traditional denoising algorithms. In addition, the method is verified using the public datasets and long-distance single-frequency experiments. In conclusion, the DCUNet model exhibit effectiveness in underwater acoustic noise suppression and robustness in different data<em>.</em></div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"233 ","pages":"Article 105611"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143096557","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":"Enhancing traffic monitoring with noise-robust distributed acoustic sensing and deep learning","authors":"Zheng Wang ,&nbsp;Taiyin Zhang ,&nbsp;Huiliang Chen ,&nbsp;Cheng-Cheng Zhang ,&nbsp;Bin Shi","doi":"10.1016/j.jappgeo.2024.105616","DOIUrl":"10.1016/j.jappgeo.2024.105616","url":null,"abstract":"<div><div>Traffic monitoring provides crucial data for intelligent transportation systems (ITS) but traditional sensors are expensive to deploy and maintain at scale. This study explores distributed acoustic sensing (DAS) using existing fiber-optic infrastructure as a cost-effective solution for traffic monitoring. While DAS offers advantages, vehicle detection signals are susceptible to noise. To address this, we propose a novel approach combining DAS with deep learning object detection using YOLOv8. Pre-processed and labeled DAS data collected over two weeks on a highway during a COVID-19 lockdown were used to train the YOLOv8 network, achieving 92 % classification accuracy. Applying the trained model revealed detailed hourly traffic patterns and vehicle compositions, demonstrating the potential of DAS for robust and cost-effective ITS. These findings highlight the effectiveness of combining DAS and deep learning for noise mitigation in traffic monitoring and provide valuable insights into traffic dynamics during the pandemic.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"233 ","pages":"Article 105616"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143096626","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":"Coupling effect of moisture desorption and matrix contraction on resistivity of water-bearing coal under high geothermal environment","authors":"Junjun Feng ,&nbsp;Yuanfang Qu ,&nbsp;Shigeng Li ,&nbsp;Chuanhua Xu ,&nbsp;Yankun Ma ,&nbsp;Qisong Huang ,&nbsp;Long Dang","doi":"10.1016/j.jappgeo.2024.105604","DOIUrl":"10.1016/j.jappgeo.2024.105604","url":null,"abstract":"<div><div>Resistivity is a key method for geophysical exploration of underground coal seams. However, the deep, high geothermal environment poses significant challenges to this approach, mainly due to moisture desorption and matrix contraction effects induced by high temperatures. In this study, experiments were conducted to assess the resistivity of water-bearing coal at varying temperatures between 30 °C and 70 °C. In addition, Nuclear Magnetic Resonance (NMR) technology was used to analyze the moisture distribution within the coal under high temperature conditions. The results indicate that moisture desorption in coal at elevated temperatures occurs in two distinct stages: a rapid desorption stage from seepage pores and a slower desorption stage from adsorption pores. As the temperature increased from 30 °C to 70 °C, the amount of moisture desorbed increased by 117 %, while the matrix contraction strain increased by 130 %. Furthermore, the variation of coal resistivity under high temperature conditions can be categorized into three stages: a transient decreasing stage due to the Soret effect, a significant increasing stage caused by moisture desorption, and a continuous decreasing stage due to coal matrix contraction. Finally, a theoretical model was developed to characterize the coupled effects of moisture desorption and matrix contraction on coal resistivity. This model provides a basis for the application of resistivity methods in deep, high-geothermal environments.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"233 ","pages":"Article 105604"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143096566","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":"Feasibility study of telluric magnetic field frequency selection method in groundwater exploration","authors":"Tianchun Yang ,&nbsp;Debing Zhu ,&nbsp;Yawar Hussain ,&nbsp;Rui Huang ,&nbsp;Qilang Yu ,&nbsp;Qijun Ding","doi":"10.1016/j.jappgeo.2024.105608","DOIUrl":"10.1016/j.jappgeo.2024.105608","url":null,"abstract":"<div><div>Over the years, scholars have made significant contributions in the development of various electric pulse of a natural field methods, collectively referred to as frequency selection method (FSM). The methods still lacking the satisfactory exploratory theoretical studies for interpreting the results effectively. In a previous study, authors concluded that results obtained at several frequencies with both telluric electrical field frequency selection method (TEFSM) and telluric magnetic field frequency selection method (TMFSM) are affected by static shift effects. The present study is dedicated to the feasibility of the methods in groundwater exploration of karst aquifer applying two-dimensional forward simulations and field measurements. In the first stage, utilizing the magnetotellurics (MT) 2D forward modeling theory, authors computed the surface horizontal electric <em>E</em>_<em>x</em> and magnetic <em>H</em>_<em>x</em> field components along the survey line in both telluric magnetic (TM) and telluric electric (TE) polarization modes. Secondly, TEFSM was used where the measured curves of electric field at different frequencies were found well synchronized in depicting the abnormal position. Further, the field testing of audio-frequency magnetotellurics (AMT) conducted with V8 electric acquisition system considerably suppressed the interferences from anthropogenic noise sources. The synchronicity of magnetic field component curves at different frequencies was worse than that of electric field component. The simulation results indicated that the component <em>E</em>_<em>x</em> exhibited significantly high-value anomalies over high resistance bodies, whereas <em>E</em>_<em>y</em> and <em>H</em>_<em>x</em> components did not show clear anomalies. All three components displayed apparent anomalies for conductive bodies. Theoretically, TMFSM is a feasible approach for exploring shallow conductive abnormal bodies, although the component <em>H</em>_<em>x</em> is susceptible to external interference in practical applications. Therefore, designing specialized magnetic sensors with strong anti-interference capability and high-accuracy is a significant step towards achieving the satisfactory results.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"233 ","pages":"Article 105608"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135603","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":"Analysis of 3D induced polarization effects of SOTEM","authors":"Wanting Song ,&nbsp;Wen Chen ,&nbsp;Yanbo Wang ,&nbsp;Weiying Chen","doi":"10.1016/j.jappgeo.2024.105613","DOIUrl":"10.1016/j.jappgeo.2024.105613","url":null,"abstract":"<div><div>The short-offset grounded-wire transient electromagnetic method (SOTEM) is characterized by observations conducted in the near-source region. When a polarizable medium is present, significant polarization field responses can be detected. Existing studies have been limited to 1D models, which have not elucidated the characteristics of polarization and induction fields for 3D polarization bodies. This paper employs the Comsol platform to construct and solve a 3D model in the frequency domain. The frequency-domain response is then transformed into a time-domain step response, achieving 3D finite element forward modeling of SOTEM with induced polarization (IP) effects. The accuracy of the 3D simulation is validated. We calculated basic 3D models containing polarized layers as well as typical high- and low-resistivity polarization bodies, analyzing the impact of IP effects on the SOTEM horizontal electric field Ex and vertical magnetic field Hz responses. It was found that the sign of the total field formed by the induced current and the polarization current determines the sign reversal phenomenon. Both the Ex and Hz components respond well to low-resistivity polarization bodies, while the Ex component demonstrates significantly better detection capabilities for high-resistivity polarization bodies. This paper provides a method for time-domain electromagnetic 3D simulation considering IP effects, offering valuable insights for advancing the application of SOTEM with IP effects in the exploration of metallic mineral resources and groundwater.</div></div>","PeriodicalId":54882,"journal":{"name":"Journal of Applied Geophysics","volume":"233 ","pages":"Article 105613"},"PeriodicalIF":2.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136392","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}