bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two-Dimensional Magnetotelluric Forward Modeling in Space-wavenumber Mixed Domain
Authors: Li Wei , Liu Jianxin , Guo Rongwen , Ji Hang 
Published: December 2023

Abstract
In magnetotelluric exploration, if you want to do 2D or 3D numerical modelling, what you need in the computational and memory requirements are potentially enormous. In order to get efficient and precise forward simulation results, we propose a new 2D numerical modelling method in space-wavenumber mixed domain. This method uses the one-dimensional Fourier transform in the horizontal directions, so the two-dimensional partial differential equations in the spatial domain can be transformed into a set of independent one-dimensional differential equations with different wave numbers. Then we can use the finite different method to solve the one-dimensional equations. In this article, the COMMEMI-2D1 model was used to verify the accuracy of the algorithm. We compare our results with the traditional finite different method in TE mode, indicating that the algorithm improves computational efficiency.
3D Electromagnetic Forward Modeling in Anisotropic Medium Using the Secondary Field Formula
Authors: Xu Jingdao , Liu Jianxin , Guo Rongwen , Li Jian 
Published: December 2023

Abstract
The electromagnetic (EM) method is an essential geophysical method to detect underground geological structures. With the increasing requirements for the reliability of data interpretation, we need an accurate anisotropic forward algorithm, which is applied several times in the inversion. At the same time, modeling the anisotropic response is an advantageous method for designing actual survey lines. In this paper, we utilize the quadratic field formulation in anisotropic media to derive the governing equations for electromagnetic fields. The governing equation is discretized using the finite difference method. Experimental results indicate that our algorithm is able to accurately model both the magnetotelluric (MT) and the controlled-source electromagnetic (CSEM) response.
Magnetotelluric Forward Modeling in Spherical Coordinate System Under Non-planar Wave Field Source
Authors: Hou Sheng , Guo Rongwen , Liu Jianxin , Li Ruiqing , Wang Yongfei , Cao Xun 
Published: December 2023

Abstract
In the traditional magnetotelluric forward modeling, the spherical earth model is typically stretched into the rectangular coordinate system using geographical projection, inevitably producing modeling errors especially for cases with large-scale data coverage. In these cases, the earth can not be considered as be flat, and the external source is not laterally uniform. In this paper, we developed a MT modeling algorithm in the spherical coordinate system based on the use of the spherical harmonic function

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for the source. A model with public solutions is used to verify our algorithm. A more realistic model is designed to show the application of our algorithm.
3D Inversion of Grounded-source Transient Electromagnetic Data
Authors: Qi Yanfu , Li Xiu , Qi Zhipeng , Zhou Jianmei , Sun Naiquan , Liu Wentao 
Published: December 2023

Abstract
The grounded-source transient electromagnetic method has the characteristics of convenient installation of emission source and large emission power, and is being widely used. To get a fine interpretation of observation data, we introduce a three-dimensional inversion algorithm for the grounded-source transient electromagnetic data. Firstly, the unstructured time-domain finite-element method is used to calculate the electromagnetic response, and then the quasi Newton method is used for data inversion. Finally, the reliability of this algorithm is verified by applying it to the theoretical model.
3D Simulation of Semi-airborne Magnetometric Resistivity Data for the Monitoring of Water-rich Fracture Zones
Authors: Chen Zhongchang , Yang Dikun 
Published: December 2023

Abstract
Fracture zones, which are commonly saturated with water, pose significant risks during underground construction and the ongoing maintenance of infrastructure projects. Detecting such objects and monitoring their stability usually require surface geophysical methods over rough terrains that are slow and expensive, sometimes even impractical if the fracture zone is underwater. In this work, we propose using the semi-airborne magnetometric resistivity (SA-MMR) method to monitor the water content in the fracture zone rapidly. SA-MMR combines the advantages of efficiency from drone-borne geophysics and high data quality because of the measurements of a steady-state magnetic field by high-precision total-field magnetometers. We design our model based on an actual water gushing accident during the tunnel construction. The accident happened when the water from a reservoir above the route gushed into the tunnel through a weathered fault zone. In our synthetic survey, we utilize a set of electrodes that act as current sources, strategically placed along the strike of the fault; the total-field magnetometer, which is suspended 5 meters above the terrain using a drone that covers the entire survey area; two identical surveys are carried out before and after the fault’s water content increases. Our 3D forward modeling indicates that despite the low-resistivity water layer above the fracture zone, the SA-MMR data anomaly can be as large as 16 nT for a 10 A source current. The magnitude of the detected anomaly in question surpasses the noise level of contemporary airborne total-field magnetometers by multiple orders of magnitude, and our study has shown that SA-MMR has great potentials in quickly and economically mapping the variation of water content in water-rich fracture zones.
BSR Characteristics and Gas Hydrate Accumulation Mechanism in Qiongdongnan Basin
Authors: Fang Xiaoyu , Zhang Jinfeng , Luo Junsheng , Xiong Pengfei , Liao Jin , Yao Zhe , Li Xushen , Zhu Jitian 
Published: December 2023

Abstract
This paper makes full use of the high-precision three-dimensional seismic data in this area, combined with the differences in the source supply, migration and accumulation mode and occurrence characteristics of hydrate gas, analyzes and summarizes the gas hydrate migration and accumulation reservoir forming model in Qiongdongnan Basin. The hydrate migration and accumulation reservoir forming models in Qiongdongnan Basin are preliminarily divided into three categories: lower-generation and upper-storage type, self-generation and self-storage type and compound mixed type. The first two categories are further divided into five sub categories, of which the lower-generation and upper-storage types are divided into four sub categories: gas chimney dominated type, mud diapir dominated type, micro-fracture dominated type and fault dominated type. The self-generation and self-storage type can be regarded as: shallow in-situ migration and accumulation type.
Detection of Seepage Paths in Dam by Electrical Resistivity Tomography
Authors: Guo Youjun , Cui Yi-An , Xie Jing , Luo Yijian , Guan Junfeng 
Published: December 2023

Abstract
The stability of the dam can be compromised by water erosion and seepage, which primarily affect the resistivity distribution underground. Seepage pathways in the dam are detected through electrical resistivity tomography (ERT), utilizing variations in resistivity for delineation. The 2D profiles show that the resistivity structure of the dam is relatively higher resistivity values (100~400Ωm), while the seepage paths exhibit significantly lower resistivity values (10–50 Ω m). it can outline five seepage paths.
Application Prospect of Airborne Electromagnetic Method in Engineering Exploration
Authors: Wang Peijian , Niu Yu , Wang Lai 
Published: December 2023

Abstract
Airborne electromagnetic method has developed rapidly since the twentieth century and has been maturely applied to uranium and polymetallic mineral exploration and railroad engineering survey in China. Engineering survey is an important foundation to guarantee the construction of cities and infrastructure in China, Further exploration of the introduction of airborne electromagnetic method in engineering survey can greatly promote the process of engineering construction in China and guarantee the strategic needs of national key projects.
Audio Magnetotelluric Imaging of a Concealed Mineral Deposit: A Case Study of Carbonate Hosted Zhugongtang lead-zinc Deposit, NW Guizhou Province, China
Authors: Pitiya Regean , Lu Mao , Chen Rujun , Nong Guanhai , Chen Siwen , Yao Hongchun , Shen Ruijie , Jiang Enhua 
Published: December 2023

Abstract
Non-intrusive geophysical exploration methods play a major role in ore deposit detection. This study aimed to characterize the subsurface electrical resistivity structure across the recently discovered super-large Zhugongtang lead-zinc deposit in north-western Guizhou province of China, using audio magnetotellurics (AMT) method. The results of this procedure were compared with available geological information. The estimated geoelectrical strike by impedance tensor invariants ranged between N285°E and N315°E. This range is consistent with known NW-SE trending structures in the Zhugongtang mining area. The obtained 2D inversion models revealed the presence of formations with an exceptionally low resistivity (< 15 Ωm), which corresponded to the known location of lead-zinc bearing formations. Moderate to low resistivity anomalies (< 63 Ωm) were observed at both shallow and greater depths. These anomalies were interpreted as indicative of geological formations composed of shale, sandstone, claystone, and silty mudstone. In addition, the resistivity models also revealed widespread high resistivity anomalies (> 1000 Ωm). These anomalies were thought to represent dolomite and limestone lithologies. In summary, the results presented in this study make a valuable contribution to the existing body of literature on the Zhugongtang deposit.
Three-Dimensional Profiling of Drilled Shafts Based on Four-Point Ultrasonic Measurement
Authors: Wang Jinchao , Wang Chuanying , Han Zengqiang , Wang Yiteng 
Published: December 2023

Abstract
Drilled piles are one of the most important foundation systems, and the shapes of the shafts prior to casting have a significant impact on their quality. In order to better obtain geometrical information on the shafts, this study proposes a profiling approach based on four-point ultrasonic measurement. First, data from horizontal sections are fitted using least squares to obtain sectional contour curves. Vertical contours are generated by iterative fitting to ensure the smoothness of the curves. Data-processing software is then used to merge the horizontal sectional curves and the vertical curves into a three-dimensional image that approximates the actual contours of the shaft.
Research and Application of 3D High Density Electrical Method
Authors: Han Yalu , Wang Yanlong , Tan Chun , Du Lizhi 
Published: December 2023

Abstract
3D high-density electrical method is a kind of artificial underground stable flow field established by setting electrodes on the ground, which is used to analyze the underground distribution of geological bodies, so as to predict or solve the problems in the planning, design and construction of projects. However, 3D high-density electrical method still has its limitations. In order to study the resolution ability of 3D high-density electrical method in actual underground cavity investigation, a comparative test of two-pole device and dipole device was established in this paper. The results show that the two-pole device can detect large depth but low resolution, while the dipole device is more affected by depth and has better effect in the measurement of low resistance abnormal body.
3D Inversion of Transient Electromagnetic Data for Concealed Karst Cavern Detection
Authors: Li Shicong , Liu Yajun , Peng Ronghua , Guo Peng , Yu Gang 
Published: December 2023

Abstract
The karst cavern is common undesirable geological body in limestone areas, which can bring great safety hazards to the construction and operation of tunnels, bridges and highways. Transient electromagnetic method (TEM) can effectively detect hidden karst structures based on the difference in electrical property between the karst cavern and the surroundings. Traditionally, 1D inversion is commonly used for the interpretation of TEM data due to its high efficiency. However, this may lead to artifacts due to 2D or 3D effects in practical surveys. In this study, we present a Gaussian-Newton approach to 3D inversion of TEM data for karst cavern detection. The numerical test on synthetic TEM data demonstrates that 3D inversion can effectively delineate the location and geometry of concealed karst cavern compared to the 1D inversion results.
Study on Geoelectrical Structure Based on Audio Magnetotelluric Inversion in Gudui, Tibet
Authors: Yan Jiahe , Zeng Zhaofa , Zhou Shuai , Ming Yuanyuan , Wang Lingxu , Zhao Jianwei 
Published: December 2023

Abstract
Gudui geothermal field in Shannan, Tibet has great potential for geothermal energy development. The main purpose of our geophysical investigation is to study the geothermal structure in this region. Therefore, 363 stations were deployed around the intersection region of numerous faults to measure AMT observe data. The 2D and 3D inversion were carried out by optimal inversion method. The result shows that the geothermal reservoir under the three springs areas combine together and the source of this reservoir comes from a deeper geothermal reservoir.
Exploration of Undercurrent Path for Hot Springs in Tibet by UAV-based Frequency Electromagnetic Induce Method
Authors: Cheng QinBo , Tan MengXin , Liu Jintao , Zhang Zhicai 
Published: December 2023

Abstract
Hot springs are useful resources for a wide range of fields, including tourist industry and power generation. In this study, an UAV-FDEM instrument is proposed, which use the unmanned aerial vehicle (UAV) to carry a multi-coil Frequency Electromagnetic induce (FDEM) instrument for scanning survey in the field. We exploit the new method to investigate the electrical conductivity (EC) distribution around the hot springs in the Yangbajing, Tibet. The results clearly present the boundary of high and low EC zones, and indicate the undercurrent path of hot spring based on the measured EC values. These discoveries by UAV-FDEM are confirmed by the electric resistivity tomography (ERT) measurements. Our investigations also reveal the causes of hot spring formation i.e., the exposure of shallow groundwater or the eruption of deep conduit hot water.
Assessment of Salinity in Fresh and Saline Aquifers in the Coastal Area of Jiangsu Province
Authors: Shang Tongxiao , Guan Yixiao , Xu Zhengwei , Hao Shefeng , Gong Xulong , Mei Rong , Liu Xiaoyu 
Published: December 2023

Abstract
Within the littoral alluvial expanse of the Yangtze River Delta, the phreatic zone encompassing the aquifer represents a prolific ecosystem, which has been subjected to an enduring epoch of marine sediment deposition, and is conspicuously susceptible to the escalating phenomenon of urbanization. The prodigious abstraction of the groundwater reserves has engendered a recent encroachment of seawater and leakage of connate saline water, culminating in the salinization of freshwater sources. For an incisive comprehension of the gradations of salinity (viz., fresh, brackish, and saline) and to execute evaluations of the groundwater’s quality, the spatial distributions of the total dissolved solids (TDS) were interpolated employing bifurcate power functions that establish a relationship between the Vertical Electrical Sounding (VES)-predicated transformation average resistivity and the assayed TDS from the systematically sampled boreholes corresponding to the aquifer stratum. The scrutiny of the groundwater’s physicochemical attributes is of paramount significance to efficaciously steer the exploitation and management of hydric resources within the area under investigation.
The CSEM Response in Horizontal Steel Casing for Geological Advance Forecast
Authors: Li Jintai , Liu Jianxin , Zhang Zihao , Liu Rong 
Published: December 2023

Abstract
Water inrush is a prevalent geological hazard that poses a significant threat to human safety and property in underground mining operations. As deep mines are being rapidly exploited through tunnel construction, accurately predicting and detecting water inrush has become increasingly crucial. The land-based controlled source electromagnetic method (CSEM) is commonly employed to identify water-bearing structures. In order to enhance its sensitivity, we have proposed a novel measurement approach for CSEM, which involves deploying electromagnetic sensors within horizontally positioned steel-cased wells embedded in the coal seam. To evaluate the feasibility of this new approach, numerical modeling was conducted using COMSOL to address the challenges posed by the casing. The influence of the steel casing was investigated, and the results demonstrated that it has minimal impact on the measured magnetic field amplitude. Moreover, the magnetic field distribution along the horizontal casing well provided straightforward indication of any anomalous bodies surrounding the coal seam. Through numerical simulations, we have validated the proposed method as a viable and effective technique for detecting water-bearing structures during deep mineral exploration.
Analysing the Relationship Between the Fault’s Distribution and the Earthquake Actives Near Gongxian China Based on Gravity Data
Authors: Xu Menglong , Yang Yabin , Sun Chengye , Chen Liang , Qiu Gengen 
Published: December 2023

Abstract
Huaying Mountain fault zone, the largest fault zone in the Sichuan Basin, is playing an important role to geological studies, such as the characterization of structural features, earthquakes occurrence, oil and gas reservoir distribution. However, the complexity and lack of consensus on deformation mechanisms necessitate further investigation of fold and thrust belts in the SB. Therefore, based on the real areal gravity exploration data and magneto-telluric (MT) data, it characterizes the spatial distribution of HMFZ in this region. Further, it gives the analysis combining the gravity anomaly, fault distribution data, and frequent earthquake activity around the study area, which provides insights that can be exploited for the evaluation of seismogenic tectonics in this region.
Investigation of Landslide by Comprehensive Geophysical Exploration in Northeast Chongqing: Taking Xiawafang Landslide as Example
Authors: Li Qiuchen , Cui Fangzi , Niu Xue , Xie Xinglong 
Published: December 2023

Abstract
Aiming at the characteristics of geological structure of Xiawafang landslide in Wuxi County, northeast Chongqing, high density resistivity method and seismic image method are used to comprehensively analyze the differences between conductivity and impedance of rock stratum in this area. At the same time, the geological survey results and drilling data are taken as the basis. With the fusion of geology-geophysics analysis and interpretation, this paper shows the characteristics of geological structure and spatial distribution in the exploration area, and landslides can be analyzed according to their mode of deformation and destruction, which provides a basis of comprehensive geology-geophysics interpretation for the treatment of geological landslide.
Practical Application of UAV Source in Complex Area Exploration
Authors: Ju Mingfeng , Qian Rongyi 
Published: December 2023

Abstract
Unmanned Aerial Vehicle(UAV) source is a new source for shallow seismic exploration. UAV source is based upon the principle of an accelerated weight drop from a high altitude. A 5-kilogram object is carried 500 meters above the surface, controlled by special remote control equipment to free fall at the exact moment we need it, and by hitting the ground at high speed, it generates a powerful amount of seismic waves. Different from traditional seismic sources, such as explosive sources and vibroseis, UAVs are not limited by terrain and it can generate seismic waves in complex environments such as mountains and rivers, with strong flexibility. Meanwhile, it’s impact object is recyclable, so the cost per excitation is minimal. In this paper, Firstly, we analyze the frequency information of the reflected signal in the seismic record obtained by the UAV source in the actual mountainous area, and then discuss the influence of different excitation positions on the record. Finally, we obtain the reflected seismic profile of the region through seismic data processing. It has been proven that UAV source can achieve low-cost and high-quality acquisition in complex environments
Study on the Three-component Response Characteristics of Ground-airborne Electromagnetic Field
Authors: Liu Zhixin , Yang Haiyan , Liu Chang 
Published: December 2023

Abstract
At any point in space, an electromagnetic field consists of three components: Hx, Hy, and Hz. The ground airborne electromagnetic method (GAEM) does not usually retrieve the Hx and Hy components of the electromagnetic field, less data may result in less accurate goaf interpretations. In this study, we numerically simulate the characteristics of the frequency-domain ground-airborne electromagnetic signal sources, quantify the induction signal distribution laws in the x-, y-, and z- directions, and identify the various factors that influence ground-airborne electromagnetic signals. The results of this study provide theoretical support for the future development of a three-component receiver for ground airborne electromagnetic field surveys. Furthermore, this data also provides information that will prove valuable in the design of field work construction.
Generative Adversarial Network Based Inversion of Cross-hole Radar Data
Authors: Zhang Donghao , Tang Yu , Qin Hui , Wang Yuanzheng , Yao Yao , Zhang Lin 
Published: December 2023

Abstract
Cross-hole radar is a popular method to characterize subsurface structures, yet traditional data interpretation methods have limitations: tomography method has poor inversion accuracy, while the full waveform inversion method costs huge computing time. In order to solve the above problems, an automatic inversion algorithm based on generative adversarial networks (GAN) is developed in this paper to interpret the permittivity from cross-hole radar B-scan images. This algorithm uses a low-resolution GAN to extract the global features in the cross-hole radar data to reconstruct the dielectric constant distribution map with low resolution, and then adopts a high-resolution GAN to enhance the resolution of the inversion results. The algorithm is trained on 1000 pairs of cross-hole radar data obtained from the finite-difference time-domain (FDTD) method. Finally, 100 pairs of similar data which has never been shown in the network are used to verify the inversion performance of the algorithm. The results show that the inversion accuracy of is greater than 90%, and the structural similarity index measure (SSIM) of the reconstructed image reaches 0.9. In addition, the proposed method also has rapid computing speed.