bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of GPR in Rebar Detection of Building Structures
Authors: Li Bo , Zhao Yonghui , Shen Ruiqing , Bi Wenda , Hu Shufan , Huang Hai 
Published: February 2021

Abstract
The detection of rebar in pillars, beams and floor slabs of building structures is a critical issue in urbanized areas. However, due to some natural and artificial objective factors, the quantity of various rebars is not always consistent with the design data, which directly affects the quality and safety of the building. To ensure structural integrity, quality inspectors must make full use of GPR testing technology. In this paper, we discuss, compare and evaluate the geophysical detection methods and effects of GPR technology regarding the possible hidden safety hazards of reinforced concrete structures. Real testing data shows that GPR detection can provide the precise quantity and positioning of rebars within buildings.
Numerical Simulation of Subsurface Penetrating Radar in Isidis Planitia on Mars for China’s First Mission to Mars
Authors: Wang Ying , Feng Xuan , Liang Wenjing , Zhou Haoqiu , Dong Zejun , Li Xiaotian , Xue Cewen 
Published: February 2021

Abstract
The water ice exploration mission is an important scientific target of China’s first Mission to Mars. The high frequency full polarimetric subsurface penetrating radar (SPR) system onboard the landing rover can carry out high-resolution imaging of the near-surface area of Mars, which is an important tool for detecting the presence of shallow water ice and soil structure. At present, most of the radar detection simulations are based on low-frequency antennas to analyze the geological structure of Mars down to several kilometers, with low resolution, which is difficult to detect the subsurface structure in the near-surface accurately. Considering topographic relief, interface roughness, subsurface rock, water ice, and permittivity changes at different layers, a three-dimensional near-surface model in the Isidis Planitia on Mars is established. The interpretation of the forward simulation results is of reference value for future Mars exploration missions.
A full-polarimetric GPR system and its application in ice crack detection
Authors: Li Xiaotian , Feng Xuan , Liang Wenjing , Xue Cewen , Zhou Haoqiu , Wang Ying 
Published: February 2021

AbstractThe warming season of Antarctica, where sea ice melts and breaks, is often the golden time for Antarctic research. But this season is also a high frequency season for the formation of ice crack, the existence of which poses a serious threat to Antarctic scientific research. Therefore, it is of important significance to monitor the trend, location, and depth of Antarctic sea ice crack in real time. Ice crack detection often uses ground penetrating radar (GPR) technology. Compared with the single-polarimetric GPR, full-polarimetric GPR can obtain more comprehensive polarization information. Therefore, a full-polarimetric GPR system based on the horn antenna is built in this paper to obtain more abundant ice crack information. Then we apply it to detect a small-scale ice crack atop frozen lakes. The analysis of the experiments and data fusion processing results can verify the effectiveness of the system for the detection of ice crack and lay the foundation for subsequent actual detection.
Multi-scale phase waveform inversion method of on-ground GPR data
Authors: Liu Xintong , Liu Sixin 
Published: February 2021

Abstract
Full waveform inversion of ground penetrating radar (GPR) based on Maxwell’s equations can invert the permittivity and conductivity of the underground medium, and achieve quantitative interpretation of the target formation. Here, we present a GPR waveform inversion method based on the phase misfit function, and inverts the phase information in the GPR data. By analyzing the characteristics of phase transformation, the misfit function of PWI is given. The gradient is constructed by the convolution of the forward and reverse fields, and its gradient formula is derived. When the transmitting source and receiver of GPR are arranged on the ground, the waveform inversion can only use the scattered field to obtain the effective information of the underground medium, and the inversion will face a strong indetermination. The inversion is more dependent on the initial model than the cross-hole GPR waveform inversion, but non-destructive detection often lacks prior information. In order to solve this problem, this paper makes use of the characteristics of integral operation and formulates a multi-scale inversion strategy. In the iterative process of inversion, high integration times are preferentially used to restore long wavelength information. This can reduce the dependence of the waveform inversion on the initial model as much as possible, implement the waveform inversion method for on-ground GPR data, and verify it with two sets of synthetic data.
On application of seismic reflection method in investigation of urban underground active faults: A case study in Jiangdong New District of Haikou in Hainan Province, China
Authors: Wang Limin , Chen Chao , Liu Jiangping , Wang Linsong , Hu Zhengwang , Hu Daogong , Jia Liyun 
Published: February 2021

Abstract
In 1605, a magnitude of 7.5 grade earthquake was occurred in the northeast of Hainan island, which caused a large area of land subsidence into sea. Previous studies have shown that the seismogenic fault of this earthquake is the Maniao-Puqian fault. About this fault, there has been a lack of in-depth research on the fault activity, the controlled subsidence process and the state of underground structure in this area since the late Cenozoic. To investigate the latest active age and the specific location distribution of the Maniao-Puqian fault, and the influence of its normal fault on the subsidence of Dongzhaigang area, detailed investigation work has been done on this fault area, through the near-surface seismic reflection method. This work can provide important technical support for the construction of Jiangdong New district of Haikou City.
Simultaneous Inversion of Multiwindow Surface Wave Dispersion Data in 2D Layered Media
Authors: Hu Shufan , Zhao Yonghui , Ge Shuangcheng , Bi Wenda , Shen Ruiqing 
Published: February 2021

Abstract
Seismic Surface Wave Methods (SWMs) have been one of the effective tools for retrieving near-surface shear-wave velocity (Vs). However, a critical problem associated with the SWMs is that using a horizontally layered model assumption in inversion may introduce blurred errors into 2D Vs imaging due to the presence of lateral variations. In addition, the increase of investigation depth necessary for the SWMs may cause an increase in errors since a wider acquisition array is essential to acquire longer wavelength data precisely. In this study, we analyzed the relationship between the output power, calculated by an amplitude normalized frequency-domain beamforming and the local phase velocity following the ray-theory approximation. Based on this relationship, we calculated the theoretical dispersion curves of multichannel surface wave data using a local maximum search algorithm. Then, we presented an algorithm for simultaneously inverting surface wave dispersion data extracted from multi-size spatial windows. We parametrized the inverted model in a 2D layered pattern. Finally, we used synthetic and field data sets to test the effectivity of the proposed method. Both results showed that the lateral resolution of the Vs model retrieved by the simultaneous inversion is improved compared to the horizontally layered model-based inversion.
Elastic FWI Without Low Frequencies Based on n-th Power Operation and Convolved Wavefields
Authors: Zhang Pan , Han Liguo , Zhao Jianwei , Yin Yuchen 
Published: February 2021

Abstract
The elastic full-waveform inversion (FWI) can use the recorded multi-component seismic data to construct high-precision multi-parameter models of the subsurface media such as P- and S-wave velocity models. However, due to the reasons such as data quality and algorithm limitations, there are still many problems in the promotion and application of elastic FWI method. Aiming at alleviating the influence of low-frequency data absence on the inversion results, we propose a robust elastic FWI method based on the n-th power operation. The n-th power of the seismic data can compress the time-domain waveform and expand its frequency-band. The FWI objective function constructed using the n-th power wavefields shows better convexity. By successively lowering the power during the inversion, we can realize a new multiscale FWI strategy, which is also a data-domain layer-stripping strategy. Seismic data will be more sensitive to the source wavelet errors after the n-th power operation. To mitigate this problem, we propose a robust objective function for elastic FWI using the n-th power operation and the convolved wavefields. Finally, the validity of the method is verified by numerical examples.
Modified Frequency-Bessel Transform Method for Dispersion Imaging of Rayleigh Wave from Ambient Seismic Noise
Authors: Xi Chaoqiang , Xia Jianghai , Dai Tianyu , Liu Ya , Ning Ling 
Published: February 2021

Abstract
Surface wave methods based on ambient noise have gained much attention from geophysical and civil engineering communities because of the limited application of traditional seismic surveys in highly populated urban areas. Higher modes information is important in dispersion curve inversion for shear-wave velocity structure. A method using the Frequency-Bessel (F-J) transform is for extracting the multimode dispersion curves from ambient seismic noise recordings. At high frequencies, the measured dispersion energy image by the F-J transform, however, would usually be polluted by a type of “crossed” artifacts. We proposed a modified frequency-Bessel (MFJ) transform by replacing the Bessel function in the F-J method with the Hankel function to attenuate the artifacts. A numerical simulation and a real-world example indicate the effectiveness of the proposed MFJ method in improving the accuracy of Rayleigh wave dispersion measurements, compared with the F-J method.
Stability analysis of constrained L1 inversion of gravity data for estimating discontinuous basement relief
Authors: Li Jiawei , Liang Qing 
Published: February 2021

Abstract
L1 inversion of gravity data is widely used to estimate the discontinuous relief of basement. We used the L1 inversion method to recover a complex model with faults, a smooth feature, and a V-shaped interface. The noise of data, the constraints with errors and the incorrect density contrast are considered in the stability analysis of inversion. The results show that the constrained L1 inversion of gravity data is stable and efficient for complex discontinuous relief of basement.
A Multi-scale Inversion Method Based on Convolutional Wavelet Transform Applied in Cross-Hole Resistivity Electrical Tomography
Authors: Pang Yonghao , Liu Zhengyu , Wang Ning , Nie Lichao , Wang Huaihong 
Published: February 2021

Abstract
With the increasing demand for fine exploration, there is also a growing demand on the use of the cross-hole electrical resistivity tomography (ERT). However, the boundaries of geological bodies cannot be accurately described when traditional smooth constraint method was adopted. To solve this problem, we studied a multi-scale inversion method based on convolution wavelet transform. The finite element method is used in the modeling process. The imaging effects of numerical simulation are discussed, such as a single rectangular target, two rectangular targets, Irregular targets, and layered models. The effectiveness of multi-scale methods in cross-hole ERT has been revealed in this work.
Rayleigh Wave Reconstruction from Ambient Noise Cross-Correlation Function by Radon-Wigner Transform
Authors: Li Xinxin , Xu Cheng , Shen Hongyan 
Published: February 2021

Abstract
The ambient noise tomography is a powerful underground-structure-detection method developed in recent years. The key of this technique is to extract Rayleigh-wave signals from cross-correlation functions (CCF). It is important to suppress the noise in Rayleigh wave signals to increase the accuracy of dispersion-curve extraction. In this paper, a Radon-Wigner Transform (RWT) method is used for Rayleigh-wave reconstruction from CCF. We first introduce the principles of RTW, and then use a multi-component synthetic seismic data to show the processing steps of RWT. Finally, we process actual ambient noise CCF with RWT to reconstruct Rayleigh waves. The results of the synthetic and actual data examples indicate that RWT successfully reconstructed the Rayleigh waves from CCF and improved the signal-to-ratio of the signal.
Groundwater Flow Monitoring via Joint Time-lapse Electrical Resistivity and Self Potential Data Tomography
Authors: Bai Lige , Li Jing , Zeng Zhaofa 
Published: February 2021

Abstract
Revealing the dynamics of groundwater movement in the vadose zone is crucial to groundwater management and artificial recharge development. In this study, the groundwater flow characterization of the pumping process is monitored by the time-lapse electrical resistivity tomography (ERT) and self-potential (SP)data tomography. The ERT data invert the resistivity distribution. Then, we combine the SP data and resistivity result to invert the apparent current density and estimate the permeability based on the Poisson equation. A total of 24 hours of time-lapse surveys are taken during the pumping and recharge of groundwater. The results show a significant increase in in resistivity and permeability during pumping water, which suggests groundwater drawdown. Similarly, significant decrease resistivity and permeability are observed during the recovery indicating groundwater recharge. These results have a significant agreement with the groundwater table monitoring result. Our experiment test suggests that combine ERT and SP data could provide a reliable way in groundwater or other hydrogeological surveys.
The application on the towed-type shallow high-accuracy seismic detection for coastal tidal flats
Authors: Yue Hangyu , Zhang Baowei , Wang Kai , Wang Xiaojiang , Zhang Kai , Wang Guangke 
Published: February 2021

Abstract
Restricted by the geological exploration equipment and tidal time, the deep seismic detection technology with large offset for exploration of oil and gas resources is often used in the seismic survey of the coastal tidal flats. Furthermore, the coastal tidal flats are only treated as the transition belt of the paralic zone, resulting in the low degree of geological exploration and low detection accuracy, which cannot meet the requirement for high-accuracy exploration in the coastal tidal flats. Conventional shallow seismic exploration technology can detect effectively the bottom interface and internal horizon of the shallow Quaternary system in the coastal tidal flats, but the equipment for data acquisition is complex, and the acquisition efficiency is low, restricting directly the seismic exploration in the coastal tidal flats. Therefore, a shallow high-accuracy seismic detection technology has been developed in this study, which is suitable for the coastal tidal flats. By making full use of the characteristics of the flat terrain in the coastal tidal flats, the method for towed data acquisition has been used, and the seismic detection equipment has been simplified in the tidal flats. With this method, the exploration cost has been reduced, and the data acquisition efficiency has been improved. The detection accuracy can reach the level of meters, and the detection depth is more than 800m with this method. With this technology, the shallow stratigraphic structure and interface in the coastal tidal flats can be detected effectively, and the location of paleochannels, concealed faults and shallow gas can be determined, which support effectively the geological survey of the coastal zone and offshore engineering, being of great practical significance for scientific disaster prevention and mitigation.
Study of mm-Wave Scattering of Roadside Targets for Vehicular Road Departure Detection Applications
Authors: Yu Yue , Feng Xuan , Liu Cai 
Published: February 2021

Abstract
The main objectives of this study were characterizing the radar scattering properties of common highway roadside objects in 24 GHz and 77 GHz bands. So far, we have developed measurement methodology and studied scattering properties of concrete curb and concrete. This paper focused on collecting initial scattering data of roadside objects under stationary. The measurements were conducted at 24 GHz with 1 GHz bandwidth using a commercial software-defined radar (SDR) manufactured by Ancortek. These measurements were mainly conducted for understanding the general scatting strength and measurement setup requirements, and were not for detail characterization of the radar cross section (RCS) properties. We also measured the reflection coefficient of concrete for spaying water. In preparation for fabricating roadside surrogates, we also began to measure the reflectivity of several conductive fabric in our possession to determine if any of them could be suitable for dressing the roadside surrogates for producing similar reflectivity as the surface of selected representative roadside objects.
One-dimensional constrained inversion of electrical source transient electromagnetic method
Authors: Nai Guoru , Wang Xuben , Xie Zhuoliang , Chen Xianjie , Liu Wei 
Published: February 2021

Abstract
The damped least squares inversion principle is applied to the transient electromagnetic one-dimensional inversion of electrical sources, and a new model is obtained by continuously iterating the initial model, thereby fitting the observed transient electromagnetic response, and performing one-dimensional inversion through induced electromotive force play. In the damped least squares inversion, constraints are added to the Jacobian matrix, and simultaneous constraint equations and conventional inversion equations are solved. By weighting the constraint parameters, the difference between adjacent resistivities and layer thicknesses is minimized. Finally, K-type and H-type theoretical models were used to verify the reliability of the algorithm, and compared with the conventional transient electromagnetic damping least squares inversion.
Mapping complex reservoir targets by electromagnetic multi-attributes
Authors: He Zhanxiang , Dong Weibin , Shen Yibin , Shi Yanlin , Zhao Yunsheng , Cao Yang 
Published: February 2021

Abstract
In development of oil and gas exploration, complex reservoirs have become a key problem for increasing production capacity. It is of great significance to develop novel technologies for reservoir prediction and evaluation. Non-seismic methods such as time-frequency electromagnetics and well-ground electromagnetics have been applied to the study of complex reservoirs, oil and gas detection methods of electromagnetic properties based on the analysis of dispersion characteristics and a method of oil and gas target identification based on complex resistivity equivalent models have been proposed and the method of inversion of electromagnetic properties of complex reservoirs using the well-ground multi-scale sequential constraint inversion method, etc., introduces the actual profiles applied to the development of exploration of igneous rocks and complicated fault-block lithological reservoirs. It provides an effective method for oil and gas detection of knew hydrocarbon traps in complex targets of oil and gas.
Inversion of Fracture Parameters in Anisotropic Coal Seam
Authors: Li Qin , Wang Wei , Ma Suibo , Zhao Bin 
Published: February 2021

Abstract
Inversion of coal seam fracture parameters is of great significance to identify and predict the distribution state of coal seam fractures, and also provides certain theoretical support for the detection and identification of coalbed methane. According to the formula of PP wave reflection coefficient, this paper uses genetic algorithm to carry out inversion of coal seam fracture parameters and Thomsen anisotropy parameters, and analyzes the accuracy and stability of inversion results. The results show that the genetic algorithm has high inversion accuracy for density, shear wave velocity and fracture density of background medium, and has certain reference significance for fracture identification.
Application of electrical resistivity tomography (ERT) in archaeological investigation of Chengsijiazi Ancient City ruins
Authors: Xin Zhonghua , Liu Lijia , Han Jiangtao , Liang Huili 
Published: February 2021

Abstract
The electrical resistivity tomography (ERT) has the characteristics of low cost, high efficiency, rich information, non-destructive exploration, and large detection depth. At present, it is being widely used in archaeological exploration. It can provide a more accurate result whether it is the preliminary survey delineation or the later detailed exploration. Chengsijiazi ancient city, located at the bank of Tao’er river, was built during the Liao and Jin dynasties. Except for the western wall destroyed by the river, the rest of the city walls were well preserved. The main target body of this survey is a part of wall foundation of an ancient building in the ancient city ruins. The ERT data are acquired along 55 survey lines and the horizontal differential field line method is introduced to interpret the inversion results of the measurement data. The horizontal differential field line method could more accurately describe the structure and boundary characteristics of the target body. The ancient building wall foundation is characterized by obvious high-gradient dense field line, so that we can accurately delineates the position of the wall base, which was excavated by archaeologists and has been verified.
Characteristic of Fault Structures in the south coastal Zone of Taizhou Based on High-Precision Aeromagnetic Data
Authors: Wang Ming , Lin Xiaoxing , Li Jiaojiao , Zhang Yongjun 
Published: February 2021

Abstract
The south coastal zone of Taizhou lies on the magmatic rock belt of southeast coast of China, which has complex regional geological structure, intense tectonic movement and frequent magmatic activities. Based on the latest high-precision aeromagnetic data, integrated interpretation was completed, combining with regional geology, regional gravity and magnetic susceptibility information. According to the block features in different zones of the RTP aeromagnetic data, the magnetic field characteristics and the relationship with the structure division were described in detail. It showed that the different characteristics of magnetic field is the concentrated reflection such as tectonic movement, magmatic activity and stratigraphic distribution, and the fault structure was inferred and studied, especially the deep and large fault structures. The fault structures were mainly distributed in NE, NNE and NW direction, with approximately equal spacing distribution. The magnetic anomaly is mainly characterized by the boundary, gradient zones and beaded anomalies in different magnetic field. The faults act not only as the important tectonic boundaries in this region, but also the important tectonic belts, controlling the distribution of mineralization. Under the interaction of these faults, they form the basic structural pattern of East-West zone and North-South block; Among them, the NE faults have the largest scale and obviously control over different magnetic field and magmatic activity. The results presented in the paper can provide reference for further study on the distribution and activity characteristics of magmatic rocks in the coastal zone.