bluuebunny/crossref_metadata_2025 huggingface dataset:
The use of soil ameliorants and fertilizers to increase the yields of rice and maize in ultisols Lampung, Indonesia
Authors: Septiyana  , Husnain  , Widowati L R , Siregar A F , Samsun A
Published: February 2021

The Ultisols has high soil acidity, Al and Fe concentration and low organic matter, nutrients, base saturation, and CEC, that limit the growth of rice and maize. The research aimed to evaluate the effectiveness of the application of fertilizers, soil ameliorant, and their combinations to improve Ultisol productivity including to increase rice and maize crops yields. This research was conducted at the Taman Bogo experimental station, Lampung Timur District, for two growing seasons (GS-1 and GS-2) in 2019. Field experiment used randomized block design with eight treatments and three replications. The treatments were included control, recommendation dosage of fertilizers (for rice: 250 kg urea ha−1, 200 kg SP-36 ha−1, 75 kg KCl ha−1; for maize: 300 kg urea ha, 175 kg SP-36 ha−1, 100 kg KCl ha−1), and combination of the recommendation dosage of fertilizers, manure, biofertilizer, and rock phosphate. Recommendation dosage of fertilizer was determined using upland soil test kit (made by Indonesian Soil Research Institute). The result showed that soil ameliorant and biofertilizer application gave significant effect to improve soil chemical physic properties and plant yields.
Analysis of peat bacterial diversity in oil palm plantations and a logged forest in Jambi, Indonesia, using PCR-DGGE technique
Authors: Pratiwi E , Satwika T D , Agus F
Published: February 2021

Jambi Province has around 617,000 hectares of peatlands spread across six districts, including Tanjung Jabung Timur. Reports on microbial diversity under different land cover, especially those using molecular techniques, were very limited. The study aimed to evaluate the impact of peatlands conversion on soil bacterial biodiversity, through the analysis of 16S-rDNA gene employing polymerase chain reaction combined with denaturing gradient gel electrophoresis (PCR-DGGE). Peat soil samples were taken from the topsoil (rhizosphere) of 3 sites, i.e. (A) conventional drained (50 to 70 cm) oil palm plantation, (B) shallow drained (30 to 50 cm) oil palm plantation, and (C) logged-over peat forest. Sequential analysis based on the 16S rRNA gene showed that 15 operational taxonomic units (OTUs) could be grouped into 3 phyla, namely Proteobacteria, Acidobacteria, and Actinobacteria. The alignment result of nucleotide shows that 4 of 15 bands of DGGE were identified as the uncultured bacterium (Sulfurospirillum, Acidobacteria, Rhodoplane, and Magnetospirillum). Overall, the Shannon-Weaver biodiversity index showed that the conversion of peatlands to oil palm plantation increased bacterial biodiversity. This could be attributed to drainage, ferlilization, and biomass inputs under the oil palm plantations. The higher biodiversity under oil palm plantations also implies a higher rate of peat decomposition under this land use, relative to the forest.
The efficacy of biofertilizer contains Bradyrhizobium japonicum isolates on soybean yields grown in Inceptisols, Bogor, West Java, Indonesia
Authors: Purwani J , Sucahyono D , Wardana I P
Published: February 2021

The use of biofertilizers is growing rapidly and promising for food crops and horticulture. They are capable to improve soil fertility, increase crop growth and yield, and environment friendly. Soybean is a strategic commodity in Indonesia. Various ways of cultural practice to improve soybean yield have been reported. The biofertilizer containing six Bradyrhizobium japonicum isolates with husk charcoal powder carrier material has been tested on soybean in Cibungbulang Bogor. Our objective was to evaluate the efficacy of Bradyrhizobium japonicum biofertilizer on soybean growth and the yield on Inceptisols Cibungbulang Bogor. The experiment was a randomized block design consisted of seven treatments with four replications. The treatments were (1) Control, no fertilizer (2) 100% NPK (3) Biofertilizer, (4) Biofertilizer + 25%NPK, (5) Biofertilizer + 50% NPK, (6) Biofertilizer + 75% NPK and (7) Biofertilizer + 100% NPK. The results showed that the promising treatment to improve soybean yield was Biofertilizer + 50% NPK and Biofertilizer + 75% NPK as indicated by significantly increase of soybean yield from 18.56 to 25.77% compared to the treatments of 100% NPK, reduced NPK fertilizer 25 to 50%. The values of Relative Agronomic Effectiveness were 191% and 165%. This study implies that the application of biofertilizer gave a positive result both on the growth and yield of soybean.
The effect of the number of rows and varieties of soybean on growth and yield in intercropping with corn
Authors: Hafid H , Syaiful S A , Kaimuddin  , Fattah A , Djufry F
Published: February 2021

Intercropping is a breakthrough in land use optimization. This study aim is to determine the effect of the number of rows and soybean varieties on the growth and yield of soybean in intercropping with corn. This study was set in a split plot design with three replication. The main plot was soybean varieties: Dena-1 (V1), Detap-1 (V2) and Deja-1 (V3), while subplots were the number of rows of soybean planting lines: Monoculture (B0), 3 rows of soybean-3 rows of corn (B1), 4 rows of soybean-3 rows of corn (B2), and 6 rows of soybean-3 rows of corn (B3). The results show that V1 has the lowest plant height as 83.04 cm. The highest number of filled pods is achieved at V2B0 with 78.53 pods but not significantly different with V2B3 as 71.77 pods. B3 gave the lowest plant height 82.74 cm, weight of 100 seeds 15.93 g, and yield weight of 1.13 t ha−1. The lowest populations of Nezara viridula and Bemisia
tabaci was produced in V2B3. The highest land equivalent ratio (LER) is achieved in V3B3 1.45. This present study shows that implementing Detap-1 with 6 rows of soybean is better than other treatment in the intercropping with corn.
Comparison of appropriate cation exchange capacity (CEC) extraction methods for soils from several regions of Indonesia
Authors: Purnamasari L , Rostaman T , Widowati L R , Anggria L
Published: February 2021

Soil-forming factors strongly influence soil diversity in Indonesia. Indonesia is rich in variations of tropical soil types that have distinctive characteristics. Cation exchange capacity (CEC) is an indicator of the soil ability to absorb and supply nutrients so that CEC is used as an index of soil chemical fertility. The factors that affected CEC are the amount of clay texture, organic matter content, and pH. In standard method, CEC is obtained by ammonium acetate 1 N pH 7 method, while the distribution of soil pH in Indonesia is very diverse from pH 4 to pH 8. Also, there are differences in factors that affect CEC, causing the CEC values to be biased or does not reflect the real conditions. The purpose of this study was to obtain the best soil CEC extraction method. 97 soil samples were analyzed with 1 N ammonium acetate extract pH 4.8, pH 6.0, pH 7.0, and compulsive cation exchange extraction method. The result showed that the ammonium acetate pH 7.0 method had a significant correlation to other methods and to pH (H2O). The ammonium acetate pH 7.0 method could be applicated for acidic and alkaline soil.
Subsurface space investigation jointly using seismic reflection and refraction tomography in urban area: a case study of Hangzhou, China
Authors: Fang Ziyan , Shi Zhanjie , Liu Jie
Published: February 2021

Seismic reflection method is one of the commonly used techniques in urban underground space exploration. However, in some areas, the effect of reflection seismic exploration is limited because of the difficulty of interpretation. In this paper, seismic reflection exploration and refraction travel time tomography are jointly used in Hangzhou to increase detection accuracy. The results show that different layers can be discerned for Quaternary sedimentary. The combined use of the two methods has obvious advantages and good practical value.
High-resolution reflected P- and SH-wave imaging for the shallow subsurface in the thick Quaternary area
Authors: Wang Kai , Feng Xuan , Wang Xiaojiang , Yue Hangyu , Zhang Baowei
Published: February 2021

For the construction of urban underground space, the shallow stratum structure from surface to 200 meters needs to be high-precision investigated. As limited in the theoretical level, the normal reflection P-wave can’t image in the very shallow subsurface especially in a thick Quaternary area. The SH-wave survey has a higher resolution in the theoretical level because the SH-wave has a lower velocity and shorter wavelength. The aim of this paper is to present a combined seismic reflection survey of P- and SH-wave in a thick Quaternary area where is close to Xiong’an New Area. By using the (λ/4) criterion, we obtain a resolution around 1.4m and 2.4 m for the SH-wave section in 9 m (v=169 m/s and f=30 Hz) and 50 m (v=209 m/s and f=22 Hz) depth separately and a resolution around 3.8m for the P-wave section in 200 meters depth (v=1878 m/s and f=125 Hz).
Monitoring surface deformation of high-speed railway using time-series InSAR method in northeast China
Authors: Meng Zhiguo , Shu Chuanzeng , Wu Qiong , Yang Ying , Fu Zhe
Published: February 2021

It is difficult to monitor the surface deformation along the high-speed railway for the complexity of the surface texture in extensive region. In this paper, based on sentinel-1A /B data, the surface deformation along the high-speed railway from Fuyu to Dehui was tried to evaluate using time-series PS-InSAR method. The results indicate that the surface deformation is not dangerous for the safe operation of the railway. Moreover, the surface depression near Dehuixi station is potentially dangerous for the safety of the railway. Finally, the cause of the surface deformation along the railway is mainly attributed to the human activity and the seasonal subgrade frost heave in the seasonal frozen soil.
Research on the detection effect of microgravity method in urban mined-out area
Authors: Zhang Youan , Lu Lichun , Deng Guocheng , Quan Haoli , Zhang Pei , Zhang Chong
Published: February 2021

The mined-out area is a potential geological hazard for urban safety. In particular, there are many mined-out areas in the Longgui nitrate mine in Guangzhou, which poses a serious threat to the safety of large-scale buildings in the city. Therefore, it is necessary to find out its specific spatial distribution location and center depth information. The micro-gravity detection method uses the residual density inversion and the re-focus weighted inversion method to identify the spatial distribution of urban underground goaf by observing the weak change of gravity field in the area The microgravity detection method combined with the effective processing and inversion interpretation method can realize the delineation of the specific distribution range and spatial distribution form of the cave in the goaf.
The Research of HuiZhou Urban Active Fault Detection
Authors: Li Yuhui
Published: February 2021

With the rapid development of society and economy, the speed of urban construction is accelerating, social wealth is rapidly gathering and the population is high. The degree of concentration is obvious and the damage caused by urban earthquakes are obviously on the rise. Underground fault zone activity causes the culprit of an urban earthquake. The ground rupture caused by the earthquake is causing damage to buildings and people’s lives. This paper studies the activity of Huizhou urban active faults by comprehensive methods such as drilling, earthquake, chronology analysis, and sedimentary environment analysis. It is determined that the Huizhou fault is an early Quaternary fault and is currently not active.
Three dimensional reverse time migration on common offset GPR data for void imaging
Authors: Wang Honghua , Gong Junbo , Liang Zhihuan
Published: February 2021

Three dimensional (3D) Reverse time migration (RTM), as an indispensable imaging technique, has been widely applied to the observed seismic data imaging. However, the RTM of Ground Penetrating radar (GPR) is usually implemented in its two-dimensional (2D) from. This paper proposes a 3D RTM algorithm on common offset GPR data for void imaging. In this algorithm, the 3D finite difference time domain (FDTD) method is applied to calculate the backward extrapolation of electromagnetic fields. And the time zero imaging condition is applied to obtain the final RTM results. Comparisons of the imaging results of 3D and 2D RTM demonstrated that the 3D RTM imaging results were superior to those of 2D RTM. And 3D spatial distribution of Void can be imaged by the proposed 3D RTM algorithm with high accuracy, which can help the subsequent interpretation of GPR profile.
Frequency 3D slice image visualization for GPR applications
Authors: He Wenchao , Hao Tong , Ke Hainan
Published: February 2021

Ground Penetrating Radar (GPR) is an efficient tool for the detection of the underground utilities. However, most data collected by GPR are in the spatial/time domain, the information in frequency domain is sometimes neglected. Joint Time-frequency Analysis (JTFA) methods are widely used to deal with the problem. In this paper, we propose a further application based on JTFA method to re-construct the frequency 3D slice image visualization (frequency C-scan) to represent the distributions of the main frequency components of the surveying area. The experiments are conducted in our sandbox with a PVC pipe buried in. After employing the proposed signal processing flow, the frequency C-scan can be re-constructed. By segmenting the frequency C-scan, frequency distribution over a surface at particular radar time/depth can be obtained. The results exhibit the capability of the proposed method to show the spatial and frequency signatures of the buried objects at certain depth.
Roadbed defect detection from ground penetrating radar B-scan data using Faster RCNN
Authors: Fang Zheng , Shi Zhensheng , Wang Xiaokai , Chen Wenchao
Published: February 2021

Ground penetrating radar (GPR) is the main technical method to detect roadbed subgrade defect. The recognition of subgrade defect is still mainly based on manual interpretation, which requires high professional knowledge of interpreters, resulting in the demand for automatic detection technology. In this paper, a solution for automatic detection of roadbed defect by implementing Faster RCNN with GPR system is presented. We simulated 30000 roadbed defect GPR B-scan data by simulation software gprMax, labeled them appropriately and automatically. Specifically, Faster RCNN was chosen, as a compromise between accuracy and ease of comparison. Preliminary detection results show that the AP (Average Precision) is 0.8067, proving that our simulation for defect is reasonable and reliable. And the Faster RCNN trained on the simulation dataset without any actual data also has excellent performance on the actual GPR data. Our method of detecting defects automatically with CNN can be easily generalized to other GPR tasks, e.g., detecting pipe, horizon extraction. It’s the biggest open-source GPR B-scan dataset as far as we know. Our simulation dataset and trained model will be made available.
Modeling of near-surface structure and Response simulation of GPR in the Jezero crater, Mars
Authors: Zhang Ling , Zeng Zhaofa , Xu Yi
Published: February 2021

NASA’s upcoming Mars 2020 will carry Ground Penetrating Radar (GPR) named RIMFAX to Mars for exploration. Mars 2020 will land at Jezero crater, located to the northwest of the Isidis basin. The landing site experienced series of geological processes such as delta formation, lavas coverage and surface weathering. Establishing the electromagnetic model here, which is used for forward simulation of RIMFAX will help the later data processing and interpretation. This paper considers the interface fluctuations, the randomness of the background medium, and the randomness of the cracks to establish a Mars near-surface electrical model, and performs forward result based on the parameters of RIMFAX. The research will support the later data processing and interpretation.
A High-resolution GPR horizon extraction method based on local reflection and global correlation
Authors: Zhu Dongyi , Shi Zhensheng , Wang Xiaokai , Chen Wenchao
Published: February 2021

Horizon extraction is a very basic and important part of ground penetrating radar (GPR) interpretation. Most GPR horizon extraction methods are based on local reflection of the GPR event such as the trace correlation algorithm, and hidden Markov model algorithm. These methods use only local structural characteristics of the GPR data and often fail to pick the layer correctly across discontinuous caused by faults and noise. In order to overcome shortcomings of the above methods, a novel method based on gradient structure tensor algorithm (GST) and dynamic time warping algorithm (DTW) is used in this paper to extract the horizon accurately which has been proved to be effective in the complex seismic data. GPR electromagnetic wave and seismic wave have certain similarity in kinematics and dynamics, we apply this method to realistic GPR data and prove its effectiveness.
Experimental study on the refinement detection at the bottom of foundation pit used by GPR in the strong interference environment
Authors: Li Yaohua , Li Xu
Published: February 2021

Due to the refraction of the detection environment and conditions, the electromagnetic waves emitted by the ground penetrating radar are susceptible to interference from external factors. The received reflected waves often have the characteristics of “weak signals and strong interference”, resulting in low sensitivity and low signal-to-noise in the collected data. Resolution tolerances cause difficulties in data interpretation. Based on the uniqueness characteristics of spectral response for the single medium, and the differences of energy intensity between effective signal and interference signal, the spectrum energy intensity analysis is introduced into signal processing in this article, the spectral response feature of different target mediums have been extract from the signal of radar reflected wave, the spectral energy strength about the underground target medium has been calculated, and the geological distribution feature of underground soil has been inversed according to three-dimensional reconstruction technology in further. It showed that this data processing method proposed in this article can remove interference and preserve effective signal which even weak and deep at the same time by the detection and application effect in the strong interference environment at the bottom of construction foundation pit, the interpretation accuracy of ground penetrating radar had improved and the purpose of refinement data processing had achieved.
Targets Imaging Method for A New MIMO Through-wall Radar
Authors: Cheng Dandan , Zeng Zhaofa , Hu Zhipeng , Kang Xiaoqian
Published: February 2021

The ultra-wideband (UWB) multi-input multi-output (MIMO) radar technique is playing a more and more important role in the application of through-wall detection because of its high resolution, lower antenna requirements, and efficient data capturing ability. A new UWB MIMO sparse array radar system with eight pairs of transmitting and receiving miniaturized Vivaldi antennas is designed in this paper and reverse time migration of the acoustic wave equation based on finite difference is used for target imaging. How to locate the target and reconstruct velocity model is the key in this paper. Finally, we found that this processing method is completely effective for forward single-target imaging, but there is still a lot of research space, and if we want to apply them in practice, further study must be done.
Stratification of Lunar Regolith Based on Attribute Analysis
Authors: Cheng Siyuan , Zhang Ling , Jia Zhuo , Zhao Xueran , Lu Qi , Liu Sixin
Published: February 2021

On December 14, 2013, China’s Chang ’e-3 missions landed on the lunar surface, providing valuable information for better study of the moon. LPR (Lunar penetrating radar) is a very important and effective detection method. The lunar surface shallow radar data we obtained through the lunar exploration radar can be used to understand the geological structure of the lunar surface and the thickness of the lunar regolith. This paper analyzes the processed LPR data of “Chang’e-3” by using instantaneous attributes, and obtains the instantaneous amplitude attributes, instantaneous phase attributes, and instantaneous frequency attributes of the radar profile. According to the results of the instantaneous attribute analysis, the lunar regolith structure of the radar profile is divided, and it is found that it can be well matched with the previous research results.
PCA applied to Data Fusion for Subsurface Target Imaging of Full-polarimetric GPR
Authors: Xue Cewen , Feng Xuan , Zhou Haoqiu , Li Xiaotian , Liang Wenjing , Wang Ying
Published: February 2021

Full-polarimetric ground penetrating radar (GPR) can obtain more comprehensive polarization data (called VV, HH, VH) for the same target than traditional commercial radar (only VV). We need to use data fusion technology to combine the polarization information of the three different polarization modes. However, the full-polarimetric GPR data fusion method has one weighted average fusion, which will mask the advantages of full polarization. Principal component analysis (PCA) is a technology of data dimensionality reduction and compression which can use VV, HH and VH as a three-dimensional data to conduct data dimensionality reduction and find the best data fusion results. In order to check the reliability, we obtained the full-polarimetric GPR data of three typical targets in the laboratory for analysis. Then we compare PCA with the weighted average fusion method by using the instantaneous amplitude and conclude that PCA can fuse full-polarimetric GPR data better than weighted average fusion.
GPR attribute analysis for the detection of LNAPL contaminated soils
Authors: Lu Qi , Wang Yan , Li Hongli
Published: February 2021

Light non-aqueous phase liquids (LNAPL) are hydrocarbons, immiscible in water and less dense than water. This paper uses GPR attribute analysis to evaluate the LNAPL contaminated soils. A GPR experiment for LNAPL leakage in a sand box is set up in the laboratory. After GPR data processing, three types of attributes are calculated. The instantaneous amplitude attribute describes the LNAPL pollution range even though the difference of electromagnetic properties is small between the target and the surrounding media. The similarity attribute delineates the boundary of LNAPL contaminated area based on the variations of the media through calculating the similarity of the adjacent traces’ waveforms and amplitude. The energy attribute helps to determine the source point of LNAPL leakage in recent LNAPL leakages. We believe that the GPR attribute analysis has a great potential to improve the interpretation of the GPR detection at actual LNAPL contaminated sites.
Three-Dimensional Inversion of Controlled-Source Electromagnetic Data in Fanchang Region, Anhui Province
Authors: Zhou Zikun , Wang Xueqiu , Yin Jian , Zhang Jinhui , Weng Aihua , Wang Tianqi
Published: February 2021

Fanchang area of Anhui Province is an important link in the middle and lower reaches of the Yangtze River. To study the distribution of rock mass near the surface of the area and the contact relationship between the strata, and to determine the possible ore body space, we carry out a 15km controlled-source electromagnetic(CSEM) survey. The observed data is the electric field amplitude data simulating wide-area electromagnetic. For the single-section electric field amplitude data of controlled source, because of the lack of magnetic field data, the impedance data needed for audio geomagnetic inversion cannot be formed. This paper uses the limited memory quasi-Newton(L-BFGS) method to perform a three-dimensional inversion with the source directly. The theoretical model test results show that the inversion method can recover the underground resistivity structure and obtain better anomalous body resolution. The three-dimensional inversion of the CSEM data in Fanchang area shows that we could get the best inversion results when the grid size is about 1/3~1/2 of the dot pitch, the background resistivity is 100 Ω·m, and the error level is 5%. The inversion result of the full-section data, including two sources, shows that the south and north end of the profile is high-resistivity, and the intermediate resistivity is low. However, in the middle of the profile, the resistivity is significantly higher than the two sides. Combined with geological data, this change reflects the distribution of strata/rock masses on the surface of the work area and the contact relationship between them. This consistency verifies the feasibility and necessity of three-dimensional source inversion for the CSEM field amplitude |Ex| data of multi-source and single profile. The underground three-dimensional resistivity structure can be effectively obtained by using the L-BFGS method with the controlled source.
Comparative Analysis on Multimode Sensitivity Kernels of Rayleigh Wave Based on Adjoint Method
Authors: Yao Yongkang , Zhang Yu , Cai Jianfeng , Zhang Shuangxi
Published: February 2021

Different modes of surface waves possess different phase velocities for each wavelength, which reflects the layer information of different depths. Penetrating depth of surface wave data is significant to determine stratigraphic models and invert their velocity structures. Instead of ray theory, we use the sensitivity kernels to investigate the relationship between multimode wavelengths and penetrating depth for a layered model based on the adjoint wave equation. We use linear Radon transform to perform Rayleigh-wave multimode separation and reconstruction. The results confirm that longer wavelength components are sensitive to deeper layers. Different modes of surface waves are sensitive to different depths. The kernels in HVL (high-velocity-layer model) and LVL (low-velocity-layer model) suggest that the velocity anomaly layer has a shielding effect on sensitivity penetrating. Rayleigh waves are insensitive to the layers beneath a velocity anomaly layer and the HVL itself.
Application of In-situ Stress Calculation in Engineering
Authors: Wang Shengao , Han Fuxing , Bing Qi
Published: February 2021

In-situ stress is an important factor affecting the stability of underground structure and the main driving force of oil and gas migration in underground. It is of great significance to the implementation of engineering, the exploitation of oil and gas and the guarantee of safety. Therefore, through the analysis of logging curves, the relevant rock mechanical parameters are extracted, then a layered model is established to calculate the ground stress and evaluate the stability of the surrounding rock. The in-situ stress obtained by parameter extraction also plays a guiding role in oil and gas exploitation and drilling target implementation.
An Automated Segment Selection Algorithm Based on the Assessment of Surface Wave Characteristic in Ambient Noise Recordings
Authors: Liu Ya , Xia Jianghai , Dai Tianyu , Xi Chaoqiang , Ning Ling , Xing Huaixue , Chang Xiaojun
Published: February 2021

Passive surface wave methods have been widely used to reconstruct velocity structures on different scales. The methods are becoming increasingly popular in urban areas because of the urgent needs of urban development. Unlike years of recordings on continental scales, the duration of recordings in urban areas usually lasts only for hours, even minutes. Thanks to huge amounts of cultural noise, especially from traffic, passive surface wave methods have proved their efficiency in urban areas, even with relatively short-time recordings. However, data needs to be processed more carefully for obtaining valuable information with limited recordings. Based on the characteristic of surface waves in − domain, we propose a formula to assess the intensity of surface waves in a linear array, thereby forming an automated data selection algorithm by selecting those segments with energetic surface waves. Results of a real-world example demonstrated the procedures of the proposed algorithm, and its effectiveness and reliability are therefore validated.
A Comparative Study on the Exploration Depth and Resolution of Winner and Schlenberg Methods Based on Potential, Current and Field Fields
Authors: Mu Qian , Liu Lijia , Han Jiangtao
Published: February 2021

High-density electrical method is widely used in hydrology, engineering, environment, and other fields. It is of great practical significance to study its exploration depth and resolution. The traditional theoretical research is to analyze and explore the exploration depth and resolution through the current density. Based on the theory of field theory, this paper proposes to study the depth and resolution of high-density electrical exploration based on a stable DC electric field. First, the derivation of the three field quantities of potential, current, and field lines in the normal field was completed, and related numerical simulation calculations were realized. Through theoretical model calculation and analysis, qualitative comparison conclusions of the two methods of Winner and Schlumberger are obtained. It is believed that the detection depth and resolution of the Winner method are lower than those of the Schlumberger, but the observation accuracy of the Winner method is higher than the Schlumberger method. Furthermore, the reliability of this conclusion is verified by physical model experiments. At the same time, the feasibility of the research on exploration depth and resolution based on the three electric field components of potential, current, and field lines is also proved.
Bidirectional Angle Limited Shortest Path Ray Tracing in Complex Topographical Conditions
Authors: Bing Qi , Sun Zhangqing , Wang Shengao
Published: February 2021

Ray tracing technology in complex topographical conditions has an important influence on mountain velocity modeling and migration imaging. In order to realize the stable and high precision ray tracing in the conditions, the bidirectional angle limited shortest path ray tracing method with under the condition of irregular calculation boundary is proposed. Firstly, based on the shortest path ray-tracing method, a new algorithm of local traveltime is given under the condition of bidirectional angle limited. Secondly, combining this algorithm with narrowband technology, a ray-tracing algorithm is proposed to adapt to arbitrary complex terrain; Then, we compare the accuracy of this method and the first-order finite-difference method; Finally, the adaptability and stability of the complex surface are verified by the calculation example, and the corresponding conclusions are given.
Numerical Analysis of Distributed Acoustic Sensing Data Full-waveform Inversion
Authors: Liu Hui , Li Jing
Published: February 2021

Distributed Acoustic Sensing (DAS) is a new type of seismic technique developed rapidly in recent years. Compared with conventional geophones, DAS receives strain rate signals with a continuous density survey. It has the advantages of low cost, high resolution, and wide application range. This abstract uses the elastic wave finite-difference method to simulate the DAS signal response and analyze surface wave dispersion characteristics. Then, we carry out 1-D dispersion curve inversion and revised 2-D DAS full-waveform inversion (FWI) tests on the DAS data under different gauge length conditions. The results show that our proposed DAS 1D dispersion inversion and 2D FWI method can provide a reliable velocity inversion result similar to conventional geophone data.
Deep learning inversion of seismic data under various observation setups
Authors: Li Duo , Cao Shuai , Yang Senlin , Xu Xinji , Jiang Peng
Published: February 2021

Deep learning has recently drawn massive attention for the task of geophysical inversion because of its strong non-linear mapping ability, especially for seismic inversion. Many works have been proposed. However, to simplify the problem, most of researchers only consider the simple observation setup and regard the task as the directive mapping between seismic data and velocity model, which limits the application in the real scenario. To solve this problem, we adopt the recent proposed SeisInvNet, which reconstructs the velocity model by treating each seismic trace as the essential element. Furthermore, we further extend its encoder part to make it accept randomly sampled traces as input so that it can be suitable for the inversion of seismic data under various observation setups. By comparing with the inversion results, we find that the modified SeisInvNet not only can adapt to various observation setups but also performs slightly better than the original method.
Research on the Universality of Convolutional Networks in Resistivity Inversion
Authors: Liu Benchao , Guo Qian , Pang Yonghao , Jiang Peng
Published: February 2021

Resistivity inversion, as an important method to study the relationship between geological models and apparent resistivity data, is a typical non-linear problem. Convolutional neural networks have huge advantages in processing complex mapping relationships between images, so they are used to solve resistivity inversion problems. The convolutional neural network’s weight sharing greatly improves the learning efficiency of the network, but there is a certain degree of incompatibility between this characteristic and the resistivity data model. In this work, the universality of the method was further verified by designing multiple complex anomalies and different background resistivities. The effectiveness of our proposed method is verified by comparing the inversion effects of different test sets with the results of traditional linear inversion.
Application of surface wave in reinforced concrete invert detection
Authors: Chen Kai , Zhang Zhifu , Zhou Yuteng
Published: February 2021

The thickness of reinforced concrete is an important parameter for tunnel safety, so it is necessary to detect it by non-destructive testing method. We used the multi-channel surface wave (MASW) method to derive velocity of tunnel lining structure in depth and detect thickness of reinforced concrete. The numerical experiment for irregularly dispersive media is conducted to simulate Rayleigh wave. The mode-kissing phenomenon in velocity spectrum is shown, and the modal dispersion curve can be inevitably misinterpreted. The field measurement is carried out on a new construction tunnel site and some Rayleigh wave data are acquired. We compute their velocity spectra. An alternative full velocity spectrum misfit function and a Bayesian inversion scheme are employed to retrieve tunnel lining structure. This study demonstrates that MASW method can effectively retrieve shear velocity of each layer in lining structure and detect the thickness of reinforced concrete inverts.
An application of electrical resistivity tomography to investigate leakage pathways in the exploitation of IREO
Authors: Chen Shu , Min Gang , Cheng Rong , Shu Rongbo , Qiu Lin , Liu Kang
Published: February 2021

For the mining of ionic rare earth ore (IREO) by in-situ leaching, the fracture structure, underground river and karst cave developed beneath the ore body, will become leakage pathways for the leaching liquors to escape and seriously reduce the recovery rate of IREO, in addition, the leach liquor along leakage pathways will also cause environmental pollution. Therefore, it is of great significance to study the deep structures and identify the leakage pathways. Our study area situates in Chang Ting county of Fujian province, which is an important rare earth deposit of China, in order to obtain high resolution deep electrical model, the electrical resistivity tomography based on multi-electrode resistivity method was used in this paper. First, we carried out multi-electrode resistivity method parameter experiment and select appropriate exploration parameters; Then, the Multi-electrode resistivity method data acquisition of 11 lines is completed by using ws-2 device mode; After that, the deep electrical structure model of the study area is obtained by inversion calculation and the thickness of the granite weathering layer (the layer containing rare earth ore) and the spatial distribution characteristics of the deep fracture structure are delineated by the deep electrical structure model of the study area. The interpretation results are consistent with the drilling results laid out in the study area. The exploration results provide important reference for the reserve evaluation of ion type rare earth mine, the sealing of leakage pathways and the layout of recovery pathways.
Application of full waveform inversion method in underground pipeline detection
Authors: Yan Xuhao , Huang Zheng , Wang Zhenyi , Zhang Pan , Zhang Fengjiao
Published: February 2021

Urban underground pipelines are an important part of today’s urban infrastructure. A comprehensive and systematic grasp of the current status of urban underground pipelines can provide people with basic information on urban planning, construction and management, and help people better develop and use cities and their underground space. Full waveform inversion is a well-known method that could reconstruct the underground velocity structures with high resolution. In this paper, we test the ability of full waveform inversion method in underground pipeline detection. The numerical test shows that we could use full waveform inversion to detect the regular urban underground pipelines in different sizes and depths.
Application of update lifting morphological wavelet and non-negative matrix factorization for wheeled and tracked vehicles classification
Authors: Ding Kai , Du Kai , Qi Xiaogang , Xu Yuelin , Cui Junqi
Published: February 2021

This paper presents an available scheme based on update lifting morphological wavelet (ULMW) and Non-negative matrix factorization (NMF) for wheeled and tracked vehicles classification. The ULWM algorithm which utilizes the update operator, means the morphological filter to replace the linear filter can preserve the impulsive shape details in seismic signal. Meanwhile the NMF method can reduce the computation cost. The traditional linear wavelet analysis and statistical analysis are compared with the presented scheme. Experimental results demonstrate that the presented scheme achieves a promising performance on extracting impulsive features of seismic signal and recognizing ground moving target.
Surface-to-Underground Nuclear magnetic Resonance Detection of Aquifer
Authors: Liu Shucai , Qiao Shuai , Jiang Zhihai , Yin Zhixian
Published: February 2021

The water hazard is one of the major accidents in coal mines. The existing geophysical exploration methods do not meet the precise requirements for exploration accuracy. Nuclear magnetic resonance (NMR) is currently the only geophysical method that can directly detect groundwater. This paper firstly introduces the basic principles and working methods of surface-to-underground NMR, and then gave the NMR response of the uniform earth excited by a circular loop source, at last, the NMR responses of some aquifers at different depths were simulated by the numerical modeling. The response for the observation underground is higher than that on the surface, which shows that the surface-to-underground NMR can increase the detection depth.
Exploration of 3D Simulation of Geothermal Field Based on Geophysics Exploration — Geothermal Geological Modeling
Authors: Zhu Yongshan , Zhao Ning , Mi Xiaoli , Wang Mengya , Li Qing , Yao Yao , Wei Zhuohan
Published: February 2021

This paper introduces a method of three-dimensional simulation of geothermal field in the study area by using the finite element method after the geothermal geological modeling based on geophysical exploration. First of all, through geophysical exploration, the three-dimensional geological model of the study area is established, and the thermal conductivity of different strata and lithology of the geological model is assigned, then the three-dimensional geothermal geological model is established;Second, set initial conditions such as surface temperature and heat source for the geothermal geological model, and then use mesh adaptive technology to perform automatic mesh division; Finally, three-dimensional geothermal field was obtained by parallel calculation in three-dimensional simulation space. This method has been applied in geothermal research in Shuguang area of Liaohe Oilfield, and the simulation results are very well.
Lithology Identification of Alluvial and Lacustrine Aquifers in Baiyangdian Area by an Airborne Transient Electromagnetic Survey
Authors: He Yiyuan , Yu Xuezhong , Liang Shengjun , Xie Rukuan , Shan Xipeng , Li Shijun
Published: February 2021

An airborne transient electromagnetic (TEM) has been conducted in Baiyangdian Area to map resistivity distribution within the alluvial and lacustrine aquifers. This investigation evaluated the reliability of resistivity models of the TEM data to infer lithological distribution in alluvial and lacustrine aquifers. The collected airborne TEM data were processed and inverted using spatially constrained 1D inversion method. And the 3D electrical structure, which maps electrical resistivity trends to depths of about 160 m, can be established through interpolation. Comparison of the resistivity models to drill logs indicates resistive permeable coarse-grained sediments and conductive fine-grained sediments which are relatively impermeable. Hence, the 3D electrical structure that are related to lateral and vertical variation in lithology, can serve as baseline information for groundwater potential identification. This research indicates that groundwater detection is an ideal target for mapping with airborne TEM techniques because of the high electrical resistivity of permeable coarse-grained deposits and its contrast with impermeable fine-grained deposits.
Using GRACE and hydrological data to estimate changes of evapotranspiration in the Three Gorges Reservoir
Authors: Zheng Yuhao , Wang Linsong , Fu Zhengyan , Peng Zhenran , Chen Chao
Published: February 2021

The Three Gorges Project (TGP) has driven changes in water storage, which directly affected the migration and redistribution of land water in the Yangtze River Basin. As a result, a new water balance is established, regional or local evapotranspiration fluctuates, and it may change the climate and weaken geological stability. In this study, we use data from GRACE gravity satellites, hydrological models, remote sensing, and in-situ observations to monitor the spatiotemporal evolution of terrestrial water changes and in the Three Gorges Reservoir (TGR) area, and then to estimate the evapotranspiration induced by water storage fluctuations in the TGR. We calculated the downscaled GRACE results based on the Land Surface Models (LSMs) and scale factor method, which can improve the signal amplitude and spatial differences in the study area and its surrounding areas. Combining the scaled GRACE-derived total water storage changes, precipitation and surface runoff, our estimated evapotranspiration (ET) in the TGR area is highly consistent with the MOD16 global ET results from 2002 to 2016. Seasonal ET changes are mainly driven by climate and rainfall, but GRACE-derived ET shown that the fluctuations of evapotranspiration are also affected by artificial water storage directly, e.g., in the main three water impounding stages (2003, 2006, and 2008), the elevation of the water level caused an abnormal increase in regional ET, but during the water drainage period (spring and autumn), high precipitation did not have a great impact on ET. Our results show that the coverage area of the reservoir area and the short-term fluctuations of the reservoir capacity are the main factors determining the ET in the TGR area.
Inspiration of magma source and intrusion of Niukutou polymetallic ore area: evidence from audio frequency magnetotelluric(AMT)
Authors: Han Song , Lu Lichun , Li Ding , Guo Hua , Chang Chang , Zheng Qiang
Published: February 2021

Niukutou research area is located in the north slope of Qimantage mountain in the east Kunlun, which is an important part of the lead, zinc, copper and iron metallogenic belt. The regional mineralization is inseparable from Indosinian magmatism. However, the research area is covered by Quaternary stratum area and the trace of magmatic activity is difficult to find. In order to further understand the underground structure, the spatial distribution characteristics of magmatic rocks and the relationship with polymetallic mineralization of the research area, the audio-frequency magnetotelluric (AMT) survey is deployed. Through the comprehensive analysis based on the electrical structure, we found that the granites encountered in the research area are from the magma source corresponding to the deep F3 channel, the granites are occurred as the veins from multi-channels. There are no granites base in the profiles and the regional metallogeny are controlled by the magma activity and the fault F3.In geologic modeling process of groundwater system, block modeling needs to be established.
Analysis of IP response characteristics in wells on undulating topography
Authors: Wang Xinyu , Yan Liangjun , Mao Yurong , Zhou Lei , Xie Xingbin
Published: February 2021

This paper studies the effect of undulating topography on resistivity method and induced polarization (IP) method between the wells. The 3D forward modeling of borehole resistivity/induced polarization method is realized by abnormal potential algorithm based on unstructured finite-element method (FEM). The algorithm is verified in layered medium and spherical abnormal bodies. We studied the response characteristics of apparent resistivity and apparent polarizability in well-well mode and the situation when the source is at different positions in the well, and analyzed the effects of undulating topography on resistivity and induced polarization. The results show that the apparent polarizability and apparent resistivity response have a great relationship with the depth of the emission source in the well, the relative position of the emission source and the measurement electrode. The undulating topography only affects the measuring electrodes at a short distance, and it has a greater impact on the low-resistance anomalous body.
Magnetotelluric multi-reference array data processing algorithm
Authors: Zhou Cong , Tang Jingtian , Yuan Yuan , Deng Juzhi , Shi Fusheng , Li Yong
Published: February 2021

Rational use of multiple remote reference data is an important way to improve the data quality of MT method. Based on the electromagnetic array data processing model, a data processing algorithm with multiple reference stations is proposed. Firstly, reference channels are selected from multiple remote stations to construct the natural field dominated reference data array; then the polarization parameters of natural sources are extracted from the reference data array by robust principal component analysis method; the parameters are then applied to the target array, which constructed by data from the stations to be processed, to estimate the target tensor impedances by robust estimation method. Finally, the effectiveness of the proposed algorithm is discussed by comparing it with the robust least squares and conventional remote reference methods, using a case study in east China. The results show that the new scheme is an effective strategy by using the multiple reference channel data, which can improve the quality of MT data processing in noisy environment and provide a reasonable correction for MT “dead band” distortions.