Chen Jiangxin, Song Hai-bin, Guan Yongxian, Yang Sheng-xiong, Bai Yang, Geng Ming‐Hui
Submarine cold seeps are widely distributed in the continental margin seas around the world. In this study, we apply a conventional multichannel seismic reflection (seismic oceanography) method to image the water column near the seafloor in order to detect cold seeps. In addition to analyzing the fluid escape structures, we also describe and discuss the development positions, seismic reflection characteristics as well as features of the cold seeps. The seismic reflection from the water column is very weak; therefore, the seismic sections above and below the seafloor are processed in two different sequences as follows:(1) geometry definition, direct wave attenuation and amplitude recovery, high-pass filter, common midpoint sorting, constant velocity (seawater sound velocity) stack, and post-stack FK filter in some sections; and (2) data quality control, amplitude recovery, 6~100 Hz bandpass filter, multiple attenuation, deconvolution, velocity analysis, normal move-out correction, common midpoint stack, post-stack noise attenuation, 4~70 Hz bandpass filter, and FX migration. The processed sections are then assembled together along the seafloor after carefully adjusting the color scale. The analysis shows that active cold seeps primarily present plume, broom, and/or irregular shapes that have weak and chaotic seismic reflections in the water column. The seismic reflection amplitude is enhanced at times; this could be attributed to the suspension of mud or particles in the water column. Cold seepage activities are typically associated with fluid escape structures, including mud diapirs, pipes, faults, fractures, gas chimneys, seabed pockmarks, and mud volcanoes. This indicates fluid migration from deep to shallow strata, fluid seepage or escape at the seafloor, as well as the formation of widespread cold seep activities. All the results herein are derived from a comprehensive interpretation of the seismic sections of the water columns and strata; however, further field studies, theoretical simulations, and experiments are required to confirm these conclusions.
{"title":"A PRELIMINARY STUDY OF SUBMARINE COLD SEEPS BY SEISMIC OCEANOGRAPHY TECHNIQUES","authors":"Chen Jiangxin, Song Hai-bin, Guan Yongxian, Yang Sheng-xiong, Bai Yang, Geng Ming‐Hui","doi":"10.1002/CJG2.30032","DOIUrl":"https://doi.org/10.1002/CJG2.30032","url":null,"abstract":"Submarine cold seeps are widely distributed in the continental margin seas around the world. In this study, we apply a conventional multichannel seismic reflection (seismic oceanography) method to image the water column near the seafloor in order to detect cold seeps. In addition to analyzing the fluid escape structures, we also describe and discuss the development positions, seismic reflection characteristics as well as features of the cold seeps. The seismic reflection from the water column is very weak; therefore, the seismic sections above and below the seafloor are processed in two different sequences as follows:(1) geometry definition, direct wave attenuation and amplitude recovery, high-pass filter, common midpoint sorting, constant velocity (seawater sound velocity) stack, and post-stack FK filter in some sections; and (2) data quality control, amplitude recovery, 6~100 Hz bandpass filter, multiple attenuation, deconvolution, velocity analysis, normal move-out correction, common midpoint stack, post-stack noise attenuation, 4~70 Hz bandpass filter, and FX migration. The processed sections are then assembled together along the seafloor after carefully adjusting the color scale. The analysis shows that active cold seeps primarily present plume, broom, and/or irregular shapes that have weak and chaotic seismic reflections in the water column. The seismic reflection amplitude is enhanced at times; this could be attributed to the suspension of mud or particles in the water column. Cold seepage activities are typically associated with fluid escape structures, including mud diapirs, pipes, faults, fractures, gas chimneys, seabed pockmarks, and mud volcanoes. This indicates fluid migration from deep to shallow strata, fluid seepage or escape at the seafloor, as well as the formation of widespread cold seep activities. All the results herein are derived from a comprehensive interpretation of the seismic sections of the water columns and strata; however, further field studies, theoretical simulations, and experiments are required to confirm these conclusions.","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":"60 1","pages":"117-129"},"PeriodicalIF":1.4,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CJG2.30032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51232487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ma Qin-zhong, Qian Jia-dong, Li Wei, Zhao Wenzhou, Fang Guoqing
The relation between the flowing characteristics of electric current and the geological structure is one of very important issues in the study of geoelectric field in seismo-electromagnetics. This paper deals with heavy currents from four different sources injected into the underground and their consequences in the observations from the network of geoelectric field stations associated with the currents, which provides us with a good opportunity to study the issues. The sources are the earth electrodes of some substations of HVDC transmission line systems in East-south China around Shanghai area (Huadong area) with the currents of 1200 to 4780A injected. The recordings of the additional signals of geoelectric field corresponding to the currents have been collected at eight geoelectric field stations in the same area. The following features could be seen in the study. ① Some stations show the selectivity effect. The magnitude of the additional geoelectric field recorded at different stations varied from one source to another, for example Pudong station is near all the heavy current sources, but only the clear signals originated from Nanqiao earth electrode were recorded while no signals from other sources (Tongli, Huaxin, and Fengxian), which shows so-called selectivity effect of the site; ② Station-source distance effect. The maximum observation distance is 350 km, beyond that no additional geoelectric signals from the sources could be recorded; ③ The source azimuth determination has complicated characteristics. For example, at Chongming station the errors are minimum, only 0.2° and 0.8°, respectively, between the actual and calculated source azimuths determined by the signals from Tongli and Xinhua earth electrodes. However, Qingpu station is the nearest station from the heavy current sources, these errors are larger than that obtained from Chongming station due to some unknown reasons; ④ The effect of non-uniformity of the geoelectric field. At the stations in the studied area, the ratios of signals from long dipole over that of short dipoles do not follow the regular patterns which appear in the cases of homogeneous medium structure underneath the observation stations, which illustrates a kind of non-uniformity effect, which is discussed in detail in this paper and proved by the results from a 2-D high density geoelectrical prospecting in the studied area. ⑤ The peculiar reverse effect of polarization direction. For the additional geoelectric field signals recorded at Qingpu and Chongming stations the polarization directions on the long diploes and short diploes are reverse, which need to be further studied in the future to explain the phenomenon. The influence of the three factors, i.e., the configuration of a point source and the electrode distribution of station, the heterogeneity of medium in a large area, as well as the fine structure of the underground medium at a station, is discussed in this paper which might give a relatively clear exp
{"title":"CHARACTERISTICS OF THE SPATIAL VARIATION OF GEOELECTRIC FIELD SIGNALS RECORDED AT THE STATIONS IN HUADONG AREA (SOUTH‐EAST CHINA) FROM 4 HEAVY CURRENT SOURCES","authors":"Ma Qin-zhong, Qian Jia-dong, Li Wei, Zhao Wenzhou, Fang Guoqing","doi":"10.1002/CJG2.30024","DOIUrl":"https://doi.org/10.1002/CJG2.30024","url":null,"abstract":"The relation between the flowing characteristics of electric current and the geological structure is one of very important issues in the study of geoelectric field in seismo-electromagnetics. This paper deals with heavy currents from four different sources injected into the underground and their consequences in the observations from the network of geoelectric field stations associated with the currents, which provides us with a good opportunity to study the issues. The sources are the earth electrodes of some substations of HVDC transmission line systems in East-south China around Shanghai area (Huadong area) with the currents of 1200 to 4780A injected. The recordings of the additional signals of geoelectric field corresponding to the currents have been collected at eight geoelectric field stations in the same area. The following features could be seen in the study. ① Some stations show the selectivity effect. The magnitude of the additional geoelectric field recorded at different stations varied from one source to another, for example Pudong station is near all the heavy current sources, but only the clear signals originated from Nanqiao earth electrode were recorded while no signals from other sources (Tongli, Huaxin, and Fengxian), which shows so-called selectivity effect of the site; ② Station-source distance effect. The maximum observation distance is 350 km, beyond that no additional geoelectric signals from the sources could be recorded; ③ The source azimuth determination has complicated characteristics. For example, at Chongming station the errors are minimum, only 0.2° and 0.8°, respectively, between the actual and calculated source azimuths determined by the signals from Tongli and Xinhua earth electrodes. However, Qingpu station is the nearest station from the heavy current sources, these errors are larger than that obtained from Chongming station due to some unknown reasons; ④ The effect of non-uniformity of the geoelectric field. At the stations in the studied area, the ratios of signals from long dipole over that of short dipoles do not follow the regular patterns which appear in the cases of homogeneous medium structure underneath the observation stations, which illustrates a kind of non-uniformity effect, which is discussed in detail in this paper and proved by the results from a 2-D high density geoelectrical prospecting in the studied area. ⑤ The peculiar reverse effect of polarization direction. For the additional geoelectric field signals recorded at Qingpu and Chongming stations the polarization directions on the long diploes and short diploes are reverse, which need to be further studied in the future to explain the phenomenon. The influence of the three factors, i.e., the configuration of a point source and the electrode distribution of station, the heterogeneity of medium in a large area, as well as the fine structure of the underground medium at a station, is discussed in this paper which might give a relatively clear exp","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":"60 1","pages":"12-30"},"PeriodicalIF":1.4,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CJG2.30024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51231473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cauchy wave field and its application in angle-domain imaging condition","authors":"Xiongwen Wang, Huazhong Wang, J. Qian","doi":"10.6038/CJG20161024","DOIUrl":"https://doi.org/10.6038/CJG20161024","url":null,"abstract":"","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":"59 1","pages":"3798-3809"},"PeriodicalIF":1.4,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71079880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Han Fei, Wang Fuxian, Liao Jinhua, Qin Huafeng, Deng Chenglong, Pan Yongxin
Understanding the magnetic properties of natural sediments, which include magnetic concentration, composition and grain size, is fundamental in paleomagnetic and paleoenvironmental studies. Systematic magnetic measurements and non-magnetic methods (e.g., transmission electron microscopy, TEM) provide detailed information of magnetic minerals. In this paper, we established a high efficient magnetic extraction method to separate magnetic minerals from surface sediments of Miyun lake in Beijing. We analyzed the bulk samples, magnetic extracts and residues. Saturation magnetization (M-s), volume magnetic susceptibility (kappa) and saturation isothermal remanent magnetization (SIRM) of the magnetic extracts is about 85%, 75% and 70% of the bulk samples, respectively. Multiple-parameter rock magnetic measurements indicated that the major magnetic minerals in sediments are multi-domain (MD) and single domain (SD) magnetite. TEM analyses revealed detrital MD titano-magnetite, biogenic SD magnetite (magnetofossils) and authigenic superparamagnetic (SP) magnetite. We propose that the combination of rock magnetism and TEM observations is useful to accurately identify the magnetic minerals in sediments.
{"title":"Identification of magnetic minerals in surface sediments of Miyun Lake, Beijing","authors":"Han Fei, Wang Fuxian, Liao Jinhua, Qin Huafeng, Deng Chenglong, Pan Yongxin","doi":"10.6038/cjg20160818","DOIUrl":"https://doi.org/10.6038/cjg20160818","url":null,"abstract":"Understanding the magnetic properties of natural sediments, which include magnetic concentration, composition and grain size, is fundamental in paleomagnetic and paleoenvironmental studies. Systematic magnetic measurements and non-magnetic methods (e.g., transmission electron microscopy, TEM) provide detailed information of magnetic minerals. In this paper, we established a high efficient magnetic extraction method to separate magnetic minerals from surface sediments of Miyun lake in Beijing. We analyzed the bulk samples, magnetic extracts and residues. Saturation magnetization (M-s), volume magnetic susceptibility (kappa) and saturation isothermal remanent magnetization (SIRM) of the magnetic extracts is about 85%, 75% and 70% of the bulk samples, respectively. Multiple-parameter rock magnetic measurements indicated that the major magnetic minerals in sediments are multi-domain (MD) and single domain (SD) magnetite. TEM analyses revealed detrital MD titano-magnetite, biogenic SD magnetite (magnetofossils) and authigenic superparamagnetic (SP) magnetite. We propose that the combination of rock magnetism and TEM observations is useful to accurately identify the magnetic minerals in sediments.","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":"8 1","pages":"2948"},"PeriodicalIF":1.4,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86585854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
X. Tang, Shaopeng Huang, Shuchun Yang, G. Jiang, Shenghui Hu
{"title":"Correcting on logging-derived temperatures of the Pearl River Mouth Basin and characteristics of its present temperature field","authors":"X. Tang, Shaopeng Huang, Shuchun Yang, G. Jiang, Shenghui Hu","doi":"10.6038/CJG20160816","DOIUrl":"https://doi.org/10.6038/CJG20160816","url":null,"abstract":"","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":"59 1","pages":"2911-2921"},"PeriodicalIF":1.4,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71079820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Qiong, Xie Chao-di, Jiang Zhan-bo, Liu Jianming
We systematically examine how dynamic stresses from seismic waves following the 2014 M(s)7. 3 Yutian, Xinjiang, earthquake affect aftershocks and regional microseismicity in the near and far field. The full Coulomb stress changes are computed based on the discrete wavenumber method. We find that the static Coulomb stress changes caused by the M(s)7. 3 earthquake discourage aftershocks occurrence in the southwestern part of the aftershock zone, which may explain why the aftershock activity in this region is relatively weak. Aftershock rates at the region about 30 km to the northeast of the mainshock are relatively high, which are consistent with positive dynamic and static stress changes in that region, with the peak values of 2. 78 MPa and 0. 80 MPa, respectively. Aftershocks about 45 km north of the mainshock are mostly triggered by the dynamic stress change with a peak value of 0. 72 MPa. The peak values of dynamic stress change in the remote Shaya and Jiashi areas are 0. 09 MPa and 0. 1 MPa, respectively, which are high enough to trigger microearthquakes in these areas. Overall the spatial distributions of dynamic stress changes induced by the Yutian mainshock show asymmetrical patterns, and there is a positive correlation between the aftershock distribution and the positive area of dynamic stress change in the northeastern and northern regions.
{"title":"Dynamically triggered aftershock activity and far-field microearthquakes following the 2014 M(s)7. 3 Yutian, Xinjiang Earthquake","authors":"W. Qiong, Xie Chao-di, Jiang Zhan-bo, Liu Jianming","doi":"10.6038/CJG20160419","DOIUrl":"https://doi.org/10.6038/CJG20160419","url":null,"abstract":"We systematically examine how dynamic stresses from seismic waves following the 2014 M(s)7. 3 Yutian, Xinjiang, earthquake affect aftershocks and regional microseismicity in the near and far field. The full Coulomb stress changes are computed based on the discrete wavenumber method. We find that the static Coulomb stress changes caused by the M(s)7. 3 earthquake discourage aftershocks occurrence in the southwestern part of the aftershock zone, which may explain why the aftershock activity in this region is relatively weak. Aftershock rates at the region about 30 km to the northeast of the mainshock are relatively high, which are consistent with positive dynamic and static stress changes in that region, with the peak values of 2. 78 MPa and 0. 80 MPa, respectively. Aftershocks about 45 km north of the mainshock are mostly triggered by the dynamic stress change with a peak value of 0. 72 MPa. The peak values of dynamic stress change in the remote Shaya and Jiashi areas are 0. 09 MPa and 0. 1 MPa, respectively, which are high enough to trigger microearthquakes in these areas. Overall the spatial distributions of dynamic stress changes induced by the Yutian mainshock show asymmetrical patterns, and there is a positive correlation between the aftershock distribution and the positive area of dynamic stress change in the northeastern and northern regions.","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":"48 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90266400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A tilted transversely isotropic (TTI) medium is a good approximation for anisotropic problems. We discuss the property of a 3D tilted transversely isotropic (TTI) medium and use pseudo P waves to simulate the P component of the elastic wave field in the weak elastic anisotropy approximation. We compare forward features of 3 second-order difference equations of pseudo P waves based on Hooke's law, elastic wave projection and dispersion equation, respectively. Now numerical calculation of these equations uses regular grid finite difference method, which is of low efficiency, low accuracy and is unstable in TTI simulation. In order to improve the calculating accuracy, this paper builds the staggered grid finite difference format for each forwarding simulation. Comparing three different numerical expressions of pseudo P wave equation in a 3D TTI medium, we find that the method based on dispersion equation is more convenient to simulate elastic P wave propagation and has lowest numerical noise. By analyzing the frequency dispersion characteristics based on different angles of isotropic symmetry axis, we introduce appropriate SV wave velocity in calculation to keep calculation stable. An example of a 2D simple synthetic model shows that the staggered grid forwarding method allow us to obtain a smooth and stable pseudo P wave field. With this strategy, 2D BP TTI reverse time migration can also achieve basically stable migration results.
{"title":"Forward modeling of pseudo P waves in TTI medium using staggered grid","authors":"Wang Luchen, Chang Xu, W. Yibo","doi":"10.6038/CJG20160325","DOIUrl":"https://doi.org/10.6038/CJG20160325","url":null,"abstract":"A tilted transversely isotropic (TTI) medium is a good approximation for anisotropic problems. We discuss the property of a 3D tilted transversely isotropic (TTI) medium and use pseudo P waves to simulate the P component of the elastic wave field in the weak elastic anisotropy approximation. We compare forward features of 3 second-order difference equations of pseudo P waves based on Hooke's law, elastic wave projection and dispersion equation, respectively. Now numerical calculation of these equations uses regular grid finite difference method, which is of low efficiency, low accuracy and is unstable in TTI simulation. In order to improve the calculating accuracy, this paper builds the staggered grid finite difference format for each forwarding simulation. Comparing three different numerical expressions of pseudo P wave equation in a 3D TTI medium, we find that the method based on dispersion equation is more convenient to simulate elastic P wave propagation and has lowest numerical noise. By analyzing the frequency dispersion characteristics based on different angles of isotropic symmetry axis, we introduce appropriate SV wave velocity in calculation to keep calculation stable. An example of a 2D simple synthetic model shows that the staggered grid forwarding method allow us to obtain a smooth and stable pseudo P wave field. With this strategy, 2D BP TTI reverse time migration can also achieve basically stable migration results.","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":"63 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2016-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84683419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The marine controlled-source electromagnetic (CSEM) method has proven to be an important addition to seismic imaging techniques in exploration of offshore hydrocarbon reservoirs and near-surface investigations. In inversion and interpretation of industrial CSEM data sets, this method can be used in a number of situations by assuming isotropy. However, the presence of electric anisotropy in the Earth's crust, due to thin layer interbedding or grain alignments in the sediments, can significantly alter the response measured by the EM receivers. Ignoring anisotropy in interpreting marine CSEM data may lead to distorted images of seabed conductivity structures, even misinterpretation.#br#In this paper, we present an inversion method for frequency domain marine controlled-source electromagnetic data generated by a titled dipole source in vertically anisotropic stratified media. This approach is based on the Gauss-Newton scheme. We extend and generalize the formulation of marine CSEM fields to calculation of the electromagnetic fields excited by arbitrarily oriented dipole sources. The partial derivatives of the electromagnetic fields with respect to both the horizontal and vertical resistivity are analytically calculated. Based on the relationship between the horizontal resistivity (ρh) and the vertical resistivity (ρv) of the inversion model, an adaptive selection method for regularization factors is proposed to balance the effects of the data misfit and the structural constraint.#br#The synthetic and real data inversion tests indicate that our inversion method can reconstruct the anisotropic resistivity of the overburden layer and the basement, and the burial depth, the thickness and the vertical resistivity of the reservoir layer can be well recovered. A better reconstruction can be obtained with multiple frequency and multiple component data sets. Combing inline and broadside geometry data sets can provide high resolution in reconstructing the burial depth of the reservoir layer and resistivity of the anisotropic basement.
{"title":"Frequency-domain inversion of marine CSEM data in one-dimensional vertically anisotropic structures","authors":"M. Luo, Li Yuguo, Gang Li","doi":"10.6038/cjg20161134","DOIUrl":"https://doi.org/10.6038/cjg20161134","url":null,"abstract":"The marine controlled-source electromagnetic (CSEM) method has proven to be an important addition to seismic imaging techniques in exploration of offshore hydrocarbon reservoirs and near-surface investigations. In inversion and interpretation of industrial CSEM data sets, this method can be used in a number of situations by assuming isotropy. However, the presence of electric anisotropy in the Earth's crust, due to thin layer interbedding or grain alignments in the sediments, can significantly alter the response measured by the EM receivers. Ignoring anisotropy in interpreting marine CSEM data may lead to distorted images of seabed conductivity structures, even misinterpretation.#br#In this paper, we present an inversion method for frequency domain marine controlled-source electromagnetic data generated by a titled dipole source in vertically anisotropic stratified media. This approach is based on the Gauss-Newton scheme. We extend and generalize the formulation of marine CSEM fields to calculation of the electromagnetic fields excited by arbitrarily oriented dipole sources. The partial derivatives of the electromagnetic fields with respect to both the horizontal and vertical resistivity are analytically calculated. Based on the relationship between the horizontal resistivity (ρh) and the vertical resistivity (ρv) of the inversion model, an adaptive selection method for regularization factors is proposed to balance the effects of the data misfit and the structural constraint.#br#The synthetic and real data inversion tests indicate that our inversion method can reconstruct the anisotropic resistivity of the overburden layer and the basement, and the burial depth, the thickness and the vertical resistivity of the reservoir layer can be well recovered. A better reconstruction can be obtained with multiple frequency and multiple component data sets. Combing inline and broadside geometry data sets can provide high resolution in reconstructing the burial depth of the reservoir layer and resistivity of the anisotropic basement.","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":"59 1","pages":"4359"},"PeriodicalIF":1.4,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71079938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wang Ben-feng, Wu Ru-Shan, C. Xiaohong, Lt, strong gt, Lu Wen-Kai lt
{"title":"Non-linear parameter estimation method based on T-matrix","authors":"Wang Ben-feng, Wu Ru-Shan, C. Xiaohong, Lt, strong gt, Lu Wen-Kai lt","doi":"10.6038/CJG20160628","DOIUrl":"https://doi.org/10.6038/CJG20160628","url":null,"abstract":"","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":"59 1","pages":"2257-2265"},"PeriodicalIF":1.4,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71079458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
He Qian-qian, Luo Shao-Cong, Sun He-ping, Lt, strong gt, Xu Jian-Qiao lt, Chen Xiao-dong
{"title":"The influence of groundwater changes on gravity observations at Jiufeng station in Wuhan","authors":"He Qian-qian, Luo Shao-Cong, Sun He-ping, Lt, strong gt, Xu Jian-Qiao lt, Chen Xiao-dong","doi":"10.6038/CJG20160804","DOIUrl":"https://doi.org/10.6038/CJG20160804","url":null,"abstract":"","PeriodicalId":55257,"journal":{"name":"地球物理学报","volume":"11 1","pages":"2765-2772"},"PeriodicalIF":1.4,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71079128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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