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Dynamic imaging of metallic contamination plume based on self-potential data

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Transactions of Nonferrous Metals Society of China 2017年第8期27卷 1822-1830页

作者： Yi-an CUI Xiao-xiong ZHU Wen-sheng WEI Jian-xin LIU Tie-gang TONG School of Geosciences and Info-Physics Central South University Changsha 410083 China Hunan Key Laboratory of Non-ferrous Resources and Geological Hazard Detection Central South University Changsha 410083 China Key Laboratory of Metallogenic Prediction of Nonferrous Metals Ministry of EducationCentral South University Changsha 410083 China

A dynamic imaging method for monitoring self-potential data was *** on the Darcy’s law and Archie’sformulas,a dynamic model was built as a state model to simulate the transportation of metallic ions in porous medium,and theNernst equation was used to calculate the redox potential of metallic ions for observation ***,the state model andobservation model form an extended Kalman filter cycle to perform dynamic *** noise added synthetic data imaging testshows that the extended Kalman filter can effectively fuse the model evolution and observed self-potential *** further sandboxmonitoring experiment also demonstrates that the self-potential can be used to monitor the activities of metallic ions and exactlyretrieve the dynamic process of metallic contamination.

关键词： dynamic imaging self-potential metallic contamination extended Kalman filter

Inversion of self-potential anomalies caused by simple polarized bodies based on particle swarm optimization

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Journal of Central South University 2021年第6期28卷 1797-1812页

作者： LUO Yi-jian CUI Yi-an XIE Jing LU He-shun-zi LIU Jian-xin School of Geosciences and Info-Physics Central South UniversityChangsha 410083China Hunan Key Laboratory of Nonferrous Resources and Geological Hazard Detection Central South UniversityChangsha 410083China Key Laboratory of Metallogenic Prediction of Nonferrous Metals Ministry of EducationCentral South UniversityChangsha 410083China

Prticle swarm optimization(PSO)is adopted to invert the self-potential anomalies of simple *** the vertical semi-infinite cylinder model as an example,the model parameters are first inverted using standard particle swarm optimization(SPSO),and then the searching behavior of the particle swarm is discussed and the change of the particles’distribution during the iteration process is *** existence of different particle behaviors enables the particle swarm to explore the searching space more comprehensively,thus PSO achieves remarkable results in the inversion of SP ***,six improved PSOs aiming at improving the inversion accuracy and the convergence speed by changing the update of particle positions,inertia weights and learning factors are introduced for the inversion of the cylinder model,and the effectiveness of these algorithms is verified by numerical *** inversion results show that these improved PSOs successfully give the model parameters which are very close to the theoretical value,and simultaneously provide guidance when determining which strategy is suitable for the inversion of the regular polarized bodies and similar geophysical problems.

关键词： self-potential inversion particle swarm optimization

Investigation of fractured rock aquifer in South China using electrical resistivity tomography and self-potential methods

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Journal of Mountain Science 2019年第4期16卷 850-869页

作者： Muhammad HASAN SHANG Yan-jun JIN Wei-jun Gulraiz AKHTER Key Laboratory of Shale Gas and Geoengineering Institute of Geology and Geophysics Chinese Academy of Sciences Institutions of Earth Science Chinese Academy of Sciences University of Chinese Academy of Sciences Department of Earth Sciences Quaid-i-Azam University

Assessment of fractured rock aquifers in many parts of the world is complicated given their strong heterogeneity. Delineation of the subsurface geological formation in the weathered terrain is essential for groundwater exploration. To achieve this goal, 2D electrical resistivity tomography(ERT) and self-potential(SP) in combination with joint profile method(JPM) and boreholes have been carried out to delineate the subsurface geological units, detect the fracture/fault zones in hard rock, monitor the groundwater flow, and estimate the groundwater reserves contained within the weathered terrain at a complex heterogeneous site of Huangbu, South Guangdong of China. The integration of resistivity images with the borehole lithology along three profiles delineates three subsurface distinct layers namely topsoil cover, weathered and unweathered layers. The incorporation of ERT and SP with JPM reveal five fractures/faults, i.e., F_1, F_2, F_3, F_4 and F_5. 2D ERT models interpret the less resistive anomalies as the fractures/faults zones, and high resistive anomalies as the fresh bedrock. The inversion program based on the smoothness-constraint is used on the resistivity field data to get more realistic three layered model. SP measurements are obtained along the same electrical profiles which provide the negative anomalies clearly indicating the groundwater preferential flow pathways along the fracture/fault zones. Hydraulic parameters namely hydraulic conductivity and transmissivity were determined to estimate the groundwater resources contained within the fractures/faults. The integrated results suggest that the fractures/faults zones are most appropriate places of drilling for groundwater exploration in the investigated area. Geophysical methods coupled with the upfront borehole data provides better understanding about the conceptual model of the subsurface geological formations. The current investigation demonstrates the importance of the integrated geophysical methods a

关键词： Electrical resistivity tomography self-potential Groundwater flow Hard rock Heterogeneity Hydraulic parameters

Detection of the Possible Buried Archeological Targets Using the Geophysical Methods of Ground Penetrating Radar (GPR) and self potential (SP), Kom Ombo Temple, Aswan Governorate, Egypt

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Geomaterials 2020年第4期10卷 105-117页

作者： Salem B. A. Yousef Mohamed H. M. Yousef Hussein F. Abd-Elsalam Mohamed A. M. Shaheen Nuclear Materials Authority Cairo Egypt

Kom Ombo temple is one of temples which were belted over high plateau close to the River Nile, near to Aswan in Egypt in the Greek-Roman period. The expected archaeological remains in the selected area are the hidden tunnels of the mummified crocodiles. The aim of the present work is to detect any of these tunnels by the application of the (GPR) and (SP) methods. The interpretation of the 10 GPR profiles revealed some locations of possible hidden tunnels. These locations show different contrasts and high amplitudes of the reflected signals, compared to the enclosing soil;also the scattering of the signals is higher than the bed layer in these locations, which may reveal the possible buried mummified crocodile tunnels in the study area. The depths of the possible targets range from 2.0 m to 2.5 m. The SP electric map shows that the study area possesses a range of about 135 mV of the potential differences between the measured stations. The positive response of the SP data is mainly concentrated at the central part of the study area. The relatively weak, negative SP anomalies may be related to moisture in the soil. The positive SP anomalies on the SP electric map display possible significant correlation between them and the inferred tunnel locations from the GPR data. The calculated depths from the SP profiles show significant agreement with that estimated from GPR data depths, which indicate that the SP electric method can be used as a successful tool in detecting buried archaeological remains in support of GPR.

关键词： Ground Penetrating Radar self-potential Kom Ombo Temple Aswan Egypt

ULF electric and magnetic anomalies accompanying the cracking of rock sample

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Acta Seismologica Sinica(English Edition) 2003年第1期16卷 113-123页

作者：郝锦绮钱书清高金田周建国朱涛 InstituteofGeophysicsandLaboratoryofTectonophysics ChinaSeismologicalBureau

The anomalies of electric-magnetic field and self-potential before earthquakes are important precursory phenom-ena. A simulating experiment study on the variations in ultra-low frequency (ULF) magnetic field and self-poten-tial during rock cracking was carried out in a magnetic field-free space. The results revealing in detail the whole process of the occurrences of electric and magnetic anomalies are significant for understanding the microscopic mechanism of ULF electric and magnetic signals. The experiment indicated that at the initial stage the slow changes in strain, self-potential and magnetic field with small amounts appeared firstly near the source of initial cracking, and then extended as the crack developed on. In the time domain, the self-potential anomaly emerged first and ULF magnetic field changes arose then. The shape of the ULF electric and magnetic anomaly varied ob-viously in early-, mid- and late-term of the test. The authors attributed the pulse-like changes of self-potential to the generation and movement of the accumulated electric charges during the cracking caused by charge separation on the crack tips within the sample. While the magnetic pulses of shorter-period at the last stage of the test, may be induced by instantaneous electric current of the accumulated charge during the cracking acceleration. The technical method and the observational results of this experiment are given in detail and the microscopic mechanism of elec-tric and magnetic precursors before earthquake are discussed in the present paper as well.

关键词： ultra-low frequency (ULF) self-potential magnetic field rock cracking magnetic field-free space