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Crustal structure of the Qiangtang and Songpan-Ganzi terranes(eastern Tibet) from the 2-D normalized full gradient of gravity anomaly
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作者 Songbai Xuan Chongyang Shen 《Geodesy and Geodynamics》 CSCD 2022年第6期535-543,共9页
Numerous geophysical studies have revealed the lithospheric structure of the Qiangtang and the Songpan-Ganzi terranes in the eastern Tibetan Plateau.However,crust-mantle evolution and crustal response to the Indian li... Numerous geophysical studies have revealed the lithospheric structure of the Qiangtang and the Songpan-Ganzi terranes in the eastern Tibetan Plateau.However,crust-mantle evolution and crustal response to the Indian lithospheric subduction are still controversial.Answering these questions requires additional information regarding crustal structure.In this study,the 2-D normalized full gradient(NFG)of the Bouguer gravity anomaly was used to investigate anomalous sources and interpret the crustal structure underneath the Qiangtang and Songpan-Ganzi terranes.The NFG-derived structures with loworder harmonic numbers(N=33 and N=43)showed that an anomalous source beneath the southern Qiangtang terrane had a characteristic northeastward-dipping shape,suggesting the northeastward motion of the crustal material induced by underthrusting Indian lithospheric mantle.The NFG images with harmonic number N=53 showed a large-scale anomalous source in the lower crust of the transformational zone from the Qiangtang terrane to the Songpan-Ganzi terrane,consistent with thickening crust and resistance of lower crustal flow.The anomalous source demonstrated by the NFG results with harmonic number N=71,located in the upper crust underneath the Ganzi-Yushu fault,suggested a seismogenic body of the 2010 M6.9 Yushu event. 展开更多
关键词 gravity anomaly normalized full gradient Crustal structures Anomalous sources Qiangtang and Songpan-Ganzi terranes
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Estimation of Depth to Salt Domes from Normalized Full Gradient of Gravity Anomaly and Examples from the USA and Denmark 被引量:3
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作者 Hamid Aghajani Ali Moradzadeh 曾华霖 《Journal of Earth Science》 SCIE CAS CSCD 2009年第6期1012-1016,共5页
We present an estimation of depth of anomalous bodies using normalized full gradient (NFG) of gravity anomaly. Maxima in the NFG map can locate the bodies and indicate their depth. Model calculation using a sphere a... We present an estimation of depth of anomalous bodies using normalized full gradient (NFG) of gravity anomaly. Maxima in the NFG map can locate the bodies and indicate their depth. Model calculation using a sphere and application of the NFG method to gravity anomalies over salt domes in the USA and Denmark shows effectiveness of the method. However, the accuracy of depth estimation strongly depends on the number of term N in the Fourier series used to calculate the NFG. An optimum N for the calculation can be given from a test. 展开更多
关键词 depth estimation anomalous body normalized full gradient gravity anomaly Fourier series.
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Refining geoid and vertical gradient of gravity anomaly 被引量:1
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作者 Zhang Chijun Bian Shaofeng +2 位作者 Yi Zhourun Liu Lingtao Fang Jian 《Geodesy and Geodynamics》 2011年第4期1-9,共9页
We have derived and tested several relations between geoid (N) and quasi-geoid (~) with model validation. The elevation correction consists of the first-term (Bouguer anomaly) and second-term (vertical gradient... We have derived and tested several relations between geoid (N) and quasi-geoid (~) with model validation. The elevation correction consists of the first-term (Bouguer anomaly) and second-term (vertical gradient of gravity anomaly). The vertical gradient was obtained from direct measurement and terrain calcula- tion. The test results demonstrated that the precision of geoid can reach centimeter-level in mountains less than 5000 meters high. 展开更多
关键词 refine GEOID QUASI-GEOID gravity anomaly vertical gradient
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Full gravity gradient tensors from vertical gravity by cosine transform 被引量:8
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作者 蒋甫玉 黄岩 燕轲 《Applied Geophysics》 SCIE CSCD 2012年第3期247-260,359,共15页
We present a method to calculate the full gravity gradient tensors from pre-existing vertical gravity data using the cosine transform technique and discuss the calculated tensor accuracy when the gravity anomalies are... We present a method to calculate the full gravity gradient tensors from pre-existing vertical gravity data using the cosine transform technique and discuss the calculated tensor accuracy when the gravity anomalies are contaminated by noise. Gravity gradient tensors computation on 2D infinite horizontal cylinder and 3D "Y" type dyke models show that the results computed with the DCT technique are more accurate than the FFT technique regardless if the gravity anomalies are contaminated by noise or not. The DCT precision has increased 2 to 3 times from the standard deviation. In application, the gravity gradient tensors of the Hulin basin calculated by DCT and FFT show that the two results are consistent with each other. However, the DCT results are smoother than results computed with FFT. This shows that the proposed method is less affected by noise and can better reflect the fault distribution. 展开更多
关键词 gravity anomaly gravity gradient tensor Fourier transform cosine transform
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Edge enhancement of gravity anomalies and gravity gradient tensors using an improved small sub-domain filtering method 被引量:4
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作者 蒋甫玉 高丽坤 《Applied Geophysics》 SCIE CSCD 2012年第2期119-130,233,共13页
In order to enhance geological body boundary visual effects in images and improve interpretation accuracy using gravity and magnetic field data, we propose an improved small sub-domain filtering method to enhance grav... In order to enhance geological body boundary visual effects in images and improve interpretation accuracy using gravity and magnetic field data, we propose an improved small sub-domain filtering method to enhance gravity anomalies and gravity gradient tensors. We discuss the effect of Gaussian white noise on the improved small sub-domain filtering method, as well as analyze the effect of window size on geological body edge recognition at different extension directions. Model experiments show that the improved small sub-domain filtering method is less affected by noise, filter window size, and geological body edge direction so it can more accurately depict geological body edges than the conventional small sub-domain filtering method. It also shows that deeply buried body edges can be well delineated through increasing the filter window size. In application, the enhanced gravity anomalies and calculated gravity gradient tensors of the Hulin basin show that the improved small sub-domain filtering can recognize more horizontal fault locations than the conventional method. 展开更多
关键词 Small sub-domain filter gravity gradient tensor edge enhancement gravity anomaly
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Distribution law and susceptibility of geohazards across a gradient belt of the Western Sichuan Plateau
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作者 LI Tianbin WANG Jianfeng +4 位作者 HE Chaoyang MENG Lubo LI Chaofei MA Junjie WEI Daqiang 《Journal of Mountain Science》 SCIE CSCD 2024年第6期1849-1867,共19页
Across a gradient belt of the Western Sichuan Plateau,geohazards have seriously limited economic and social development.According to incomplete statistics,15,673 geohazards have been recorded in the study area.In orde... Across a gradient belt of the Western Sichuan Plateau,geohazards have seriously limited economic and social development.According to incomplete statistics,15,673 geohazards have been recorded in the study area.In order to mitigate the threat of geohazards to human engineering activities in the region,an overall understanding of the distribution pattern of geohazards and susceptibility assessment are necessary.In this paper,a gradient belt of the Western Sichuan Plateau and its zoning criteria were defined.Subsequently,on the basis of relief amplitude,distance to faults,rainfall,and human activities,three indicators of endogenic process were introduced:Bouguer gravity anomaly gradient,vertical deformation gradient,and horizontal deformation gradient.Thereafter,the distribution patterns of geohazards were investigated through mathematical statistics and ArcGIS software.By randomly selecting 10,449 hazards,a geohazard susceptibility map was generated using the Information Value(IV)model.Finally,the IV model was validated against 5224 hazards using the Area Under Curve(AUC)method.The results show that 47.6%of the geohazards were distributed in the zone of steep slope.Geohazards showed strong responses to distance to faults,human activities,and annual rainfall.The distribution of geohazards in the gradient belt of the Western Sichuan Plateau is more sensitive to vertical internal dynamics factors(such as vertical deformation gradient and Bouguer gravity anomaly gradient)without any apparent sensitivity to horizontal internal dynamics factors.The areas of high and very-high risk account for up to 32.22%,mainly distributed in the Longmenshan and Anning River faults.According to the AUC plot,the success rate of the IV model for generating the susceptibility map is 76%.This susceptibility map and geohazard distribution pattern can provide a reference for geological disaster monitoring,preparation of post-disaster emergency measures,and town planning. 展开更多
关键词 gradient belt GEOHAZARDS Distribution law Bouguer gravity anomaly gradient Vertical deformation gradient SUSCEPTIBILITY
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Application of high-precision gravity in fracture identifi cation:a case study of the Miquan region of the Junggar Basin
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作者 Jiang Ning Li Zhu-qiang +2 位作者 Wang Yin Bao Yi Wang Jun 《Applied Geophysics》 SCIE CSCD 2024年第4期869-877,882,共10页
The gravity gradient anomaly zone is produced due to density diff erences on both sides of a fault.Tracking of extreme points enables the characterization and description of fault locations.However,for some deep-seate... The gravity gradient anomaly zone is produced due to density diff erences on both sides of a fault.Tracking of extreme points enables the characterization and description of fault locations.However,for some deep-seated faults with large burial depths and secondary faults with moderate burial depths,the gravity horizontal total gradient anomaly must be enhanced using the concept of dip angle to strengthen the weak anomaly extraction for the identification of more fault information.This method was used to predict five regional deep-seated faults and six secondary faults in the Miquan region.The fracture plane extends in a near north-northeast direction;that is,it mostly expands out of the study area,spreads out in a trumpet shape to the southwest,and converges to the northeast.Fracture activity is an important factor in controlling structural units or local structures.The Miquan block is located in a complex structural zone in front of the Bogeda Mountains,which have very complex surface and subsurface geological conditions,and seismic data are unideal.Therefore,fracture prediction results using gravity data are important in-depth understanding of the structure in this area. 展开更多
关键词 fracture identifi cation gravity anomaly gravity level total gradient gravity tilt angle Miquan region
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Theoretical simulation of the effect of deformation on local gravity in a density gradient zone 被引量:1
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作者 Zhu Liangyu Wang Qingliang Zhu Yiqing 《Geodesy and Geodynamics》 2013年第4期9-16,共8页
We modeled the effect of the deformation of a Density Gradient Zone (DGZ) on a local gravity field using a cubical model and introduced a new method to simulate a complex DGZ (CDGZ). Then, we analyzed the features... We modeled the effect of the deformation of a Density Gradient Zone (DGZ) on a local gravity field using a cubical model and introduced a new method to simulate a complex DGZ (CDGZ). Then, we analyzed the features of the model for the influence of the deformation of the DGZ on the local gravity field. We concluded that land-based gravity is not sensitive to the thickness of the DGZ and that the magnitude of the contribution of the DGZ is one order less than that of the volume strain with the same displacement. 展开更多
关键词 Density gradient Zone (DGZ) density interface cubical model vertical deformation gravity anomaly
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Interpretation of Gravity Anomalies by Multi-Scale Evaluation of Maxima of Gradients and 3D Modelling in Bipindi Region (South-West Cameroon)
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作者 Fidèle Koumetio Donatien Njomo +3 位作者 Constant Noutchogwe Tatchum Alain Pierre Kamga Tokam Tabod Charles Tabod Eliezer Manguelle-Dicoum 《International Journal of Geosciences》 2014年第12期1415-1425,共11页
The gravity maps display, in Bipindi zone, local oval culminations of low anomalies indicative of a presence of intrusive light body in a subsurface but the nature, the form and the position of this body are still unk... The gravity maps display, in Bipindi zone, local oval culminations of low anomalies indicative of a presence of intrusive light body in a subsurface but the nature, the form and the position of this body are still unknown. The analyses of established gravimetric anomaly maps, the multi-scale evaluation of maxima of gradients and the quantitative interpretation of residual anomalies by 3D modelling permit characterizing the intrusive light body situated at Bipindi. The multi-scale evaluation of maxima of gradients shows that the modelling of the intrusive light body of Bipindi can be done without the problem of interference of anomalies from different sources. The 3D model of Bipindi zone shows two dissymmetrical blocks of the same type of rock with a density contrast of -0.095 g·cm-3 in comparison with the density of the surrounding metamorphic rocks. The two blocks are at a distance about 3 km from one to another. The upper surfaces of these blocks lie at a depth between 1 and 2 km. Their lower surfaces have two landings;one lies at a depth of about 8 km and another at a depth about 14 km. A consideration of the density of the modelled body, of the ranges of densities of specific rocks present in the general region indicates that the body may be composed of nepheline syenites. The intrusive body of Bipindi is situated in a senestral shear zone. The area situated between the two blocks of this intrusive body may be indicated for a detail study in the domain of mineral research. 展开更多
关键词 gravity ANOMALIES MAXIMA of gradients RESIDUAL ANOMALIES Modelling
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Combined analysis of gravity and magnetic anomalies using normalized source strength
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作者 LI Lu ZHANG Shuang 《Global Geology》 2018年第2期127-133,共7页
The traditional combined gravity and magnetic analysis uses the linear regression of the first order vertical derivative of the gravity anomaly and the reduction to the pole(RTP) magnetic anomaly,and provides the quan... The traditional combined gravity and magnetic analysis uses the linear regression of the first order vertical derivative of the gravity anomaly and the reduction to the pole(RTP) magnetic anomaly,and provides the quantitative or semi-quantitative interpretation by calculating the correlation coefficient,slope,and intercept.In the calculation process,due to the remanent magnetization,the RTP anomaly still contains the effect of oblique magnetization,as a result,the homologous gravity and magnetic anomalies may display irrelevant results in the linear regression calculation.To solve this problem,we present a new combined analysis using normalized source strength(NSS).Based on the Poisson's relation,the gravity field can be transformed into the pseudomagnetic field of the direction of geomagnetic field magnetization under the homologous condition.The NSS of the pseudomagnetic field and that of the original magnetic field are calculated,which are insensitive to the remanence,and then the linear regression analysis is carried out.The approach is tested using synthetic model under complex magnetization,the results show that it can still identify the gravity and magnetic anomalies from same source under strong remanence,and can establish the Poisson's ratio.Finally,this approach is applied in Wudalianchi in China.The results demonstrated that this approach is feasible and can provide the reference for further data processing and interpretation. 展开更多
关键词 gravity anomaly MAGNETIC anomaly normalized SOURCE STRENGTH remanent MAGNETIZATION
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Polar 3D Transformation of the Full Gradient of Attractive Potential
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作者 Gennady Prostolupov Michail Tarantin 《International Journal of Geosciences》 2012年第2期329-332,共4页
The method of 3D polar transformation of full gravity potential gradient vectors is based on the geometric properties of the crossing points of complete gradient of the potential to localize the source region that cau... The method of 3D polar transformation of full gravity potential gradient vectors is based on the geometric properties of the crossing points of complete gradient of the potential to localize the source region that causes the observed anomaly. The cross-points—poles—are defined for rectangular polygons of different sizes where the full gradient vector is defined at every vertex. The polygon size range could be specified. The set of poles, positive and negative, is then represented on the 3D chart in the form of clusters of dots or cubes and can be considered as a model image of the sources, intended for visual analysis and further interpretation. 展开更多
关键词 gravity anomaly Interpretation Model Vector full gradient 3D CHART
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Gravity pattern in southeast margin of Tibetan Plateau and its implications to tectonics and large earthquakes 被引量:14
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作者 Yue Wu Yuan Gao 《Earth and Planetary Physics》 CSCD 2019年第5期425-434,共10页
There are many active faults in the southeast margin of Tibetan Plateau,where three large active faults zones,the Longmenshan,Xianshuihe and Anninghe,merge to form a"Y"shape.Strong crustal deformation and a ... There are many active faults in the southeast margin of Tibetan Plateau,where three large active faults zones,the Longmenshan,Xianshuihe and Anninghe,merge to form a"Y"shape.Strong crustal deformation and a complicated fault distribution accompany strong earthquake activity in this zone.In this paper,we investigate a multi-scale gravity anomaly in the southeastern margin of the Tibetan Plateau using the wavelet transform;we find that the pattern of the gravity field is closely related to the fault system in the study area.Analyzing the characteristics of this Bouguer gravity anomaly at different orders indicates that the eastern Himalayan syntaxis has produced a strong eastward push during its northward movement,resulting in a shortening of the crust from west to east and a rapid uplift of the Tibetan Plateau.The Songpan–Garzêand Sichuan–Yunnan blocks have been forced to slip and extrude southward and eastward laterally.The distributions of seven large earthquakes from 1970 to 2018 reflects the relationship between large earthquakes and characteristics of the gravity anomaly.Comparing the tectonic backgrounds of several earthquakes reveals that the large earthquakes occur usually in the high gravity anomaly gradient zone,which corresponds in general to the boundary zones of the blocks.We infer that large earthquakes occur primarily in high Bouguer gravity anomaly zones in the upper crust,while low Bouguer gravity anomalies encompass the lower crust and the uppermost mantle. 展开更多
关键词 SOUTHEAST MARGIN of Tibetan Plateau Bouguer gravity anomaly(BA) wavelet transform(WT)and multiscale analysis(MA) FOCAL mechanism of earthquake gradient zone
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Simultaneous Modelling of Gravity and Magnetic Data in a Measured Heat Flux Area to Characterize Geothermal Heat Sources: A Case for Eburru Geothermal Complex, Kenya 被引量:1
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作者 Erick Rayora Nyakundi Githiri J. Gitonga Maurice O. K’Orowe 《Journal of Geoscience and Environment Protection》 2021年第5期40-54,共15页
Forward modelling of gravity and magnetic data was done simultaneously to show the correlation between gravity and magnetic anomalies on a measured heat flux region. The results were used to characterize the heat sour... Forward modelling of gravity and magnetic data was done simultaneously to show the correlation between gravity and magnetic anomalies on a measured heat flux region. The results were used to characterize the heat source structures in Eburru area. Modelling was done using Oasis montaj geosoft software which is an iteration process where the gravity and magnetic anomalies were calculated and compared to the observed residual anomaly until there was a fit. The start model was constructed based on depths from Euler deconvolution and models constrained using stratigraphy data from the existing wells in the study area. <span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">Forward modelling of gravity and magnetic data revealed intrusions within the Earth’s subsurface with depth to the top of the sources ranging from </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">739 m</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> to </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">5811 m</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">. The density of the sources ranges between </span></span></span></span><span><span><span><span style="font-family:""><span style="font-family:Verdana;">3.0 g/cm</span><sup><span style="font-family:Verdana;">3</span></sup></span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> and </span></span></span></span><span><span><span><span style="font-family:""><span style="font-family:Verdana;">3.2 g/cm</span><sup><span style="font-family:Verdana;">3</span></sup></span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> while their magnetic susceptibility was zero. This implies that intrusions from the mantle with a magnetic susceptibility of zero have temperatures exceeding the curie temperature of rocks. The density of the intrusions modelled was higher than 2.67 </span></span></span></span><span><span><span><span style="font-family:""><span style="font-family:Verdana;">g/cm</span><sup><span style="font-family:Verdana;">3</span></sup></span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">, the average crustal density, hence it explains the observed positive gravity anomaly. </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">The results also revealed that areas with high heat flux have shallow heat sources and if the heat sources are deep, then there must be a good heat transfer mechanism to the surface.</span></span></span></span> 展开更多
关键词 Forward Modelling gravity anomaly Magnetic anomaly Heat Source Heat Flux Geothermal gradient Eburru
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Gravity anomaly and crustal density structure in Jilantai rift zone and its adjacent region
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作者 Guiju Wu Chongyang Shen +1 位作者 Hongbo Tan Guangliang Yang 《Earthquake Science》 CSCD 2016年第4期235-242,共8页
This paper deals with the interpretation of Bouguer gravity anomalies measured along a 250 km long Suhaitu-Etuokeqi gravity profile located at the transitional zone of the Alxa and Ordos blocks where geophysical chara... This paper deals with the interpretation of Bouguer gravity anomalies measured along a 250 km long Suhaitu-Etuokeqi gravity profile located at the transitional zone of the Alxa and Ordos blocks where geophysical characteristics are very complex. The analysis is carried out in terms of the ratio of elevation and Bouguer gravity anomaly, the normalized full gradient of a section of the Bouguer gravity anomaly (Gh) and the crustal density structure reveal that (1) the ratio of highs and lows of elevation and Bouguer gravity anomaly is large between Zhengyiguan fault (F4) and Helandonglu fault (F6), which can be explained due to crustal inhomogeneities related to the uplift of the Qinghai-Tibet block in the northeast; (2) the main active faults correspond to the Gh contour strip or cut the local region, and generally show strong deformation characteristics, for example the Bayanwulashan mountain front fault (F1) or the southeast boundary of Alxa block is in accord with the western change belt of Gh, a belt about 10 km wide that extends to about 30 km; (3) Yinchuan- Pingluo fault (FS) is the seismogenic structure of the Pin- gluo M earthquake, and its focal depth is about 15 km; (4) the Moho depth trend and Bouguer gravity anomaly vari- ation indicates that the regional gravity field is strongly correlated with the Moho discontinuity. 展开更多
关键词 Yinchuan-Helanshan uplift Jilantai rift zone gravity profile Bouguer gravity anomaly Crustal densitystructure normalized full gravity gradient SEISMOGENESIS
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Determination of vertical gradient of gravity anomaly with topographic data 被引量:4
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作者 ZHANG ChijunInstitute of Geodesy and Geophysics , Chinese Academy of Sciences , Wuhan 430077 , China 《Chinese Science Bulletin》 SCIE EI CAS 1999年第11期1029-1034,共6页
The role of vertical gradient of gravity anomaly in the solution and interpretation of geological and geophysical problems on superficial layer is increasingly evident. However, it is difficult to directly observe the... The role of vertical gradient of gravity anomaly in the solution and interpretation of geological and geophysical problems on superficial layer is increasingly evident. However, it is difficult to directly observe the vertical gradient of gravity anomaly in mountainous area. Moreover,aerial and satellite gravity gradient measurments have not been put into practice up to date yet.The vertical gradient of gravity anomaly is calculated by use of topographic data and several problems concerned are investigated and discussed. It turns out in theory and practice that the relative error of the vertical gradient determined with the method is only 5%, and when the vertical gradient of gravity anomaly reaches the maximum 1 000 ns<sup>-2</sup> the error is only 50 ns<sup>-2</sup>. In addition, how to divide ring zones in calculation and the errors caused by the inaccuracy of landform elevation and rock density has been quantitatively analysed. 展开更多
关键词 VERTICAL gradient gravity anomaly topographic MASS geoid.
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An Expression for Gravity Generated by an Anomalous Geological Body and Its Application in Bathymetry Inversion 被引量:4
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作者 Huan XU Jinhai YU +1 位作者 Xiaoyun WAN Lei LIANG 《Journal of Geodesy and Geoinformation Science》 2021年第4期63-73,共11页
The gravity anomaly and vertical gravity gradient due to anomalous geological bodies are mainly computed by numerical methods,so it is difficult and time-consuming to use the gravity-geological method to invert seaflo... The gravity anomaly and vertical gravity gradient due to anomalous geological bodies are mainly computed by numerical methods,so it is difficult and time-consuming to use the gravity-geological method to invert seafloor topography.This paper addresses this issue by deriving an expression for gravity generated by a cylinder based on a series expansion.The choice of number for terms in the series is estimated by comparing with the numerical method,especially when the depth H=4000m,the accuracy of 1 mGal(1 Gal=10^(-2)m/s^(2))can be achieved when the series are 9.The expressions can be used to establish the relationships between the shape of an anomalous body and the generated vertical gravity and vertical gravity gradient,respectively.Finally,the potential applications of the expressions in inverting seafloor topography are illustrated by synthetic examples. 展开更多
关键词 gravity-geological method anomalous geological body vertical gravity anomaly vertical gravity gradient anomaly
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融合多源海洋大地测量数据的南海海底地形多层感知机反演
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作者 周帅 刘新 +5 位作者 李真 祝程程 袁佳佳 李静静 郭金运 孙和平 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2024年第4期1368-1382,共15页
本文融合SIO(Scripps Institution of Oceanography)发布的垂线偏差、重力异常和垂直重力梯度数据及NCEI(National Centers for Environmental Information)发布的船载测深数据,利用多层感知机神经网络(Multi-Layer Perceptron,MLP)建... 本文融合SIO(Scripps Institution of Oceanography)发布的垂线偏差、重力异常和垂直重力梯度数据及NCEI(National Centers for Environmental Information)发布的船载测深数据,利用多层感知机神经网络(Multi-Layer Perceptron,MLP)建立南海海域(108°E—121°E,6°N—23°N)分辨率为1'×1'的海底地形模型(MLP_Depth).首先,将642716个船载测深控制点的位置信息与周围4'×4'格网点处的地球重力信息(垂线偏差、重力异常、垂直重力梯度)作为输入数据,将船载测深控制点处实测水深值作为输出数据,训练MLP神经网络模型,训练结束时决定系数R2为99%,平均绝对误差MAE为39.33 m.然后,将研究区域内1'×1'格网正中心点处的输入数据输入于MLP模型中,可得格网正中心点处的预测海深值.最后,根据预测海深值建立研究区域范围内分辨率为1'×1'的MLP_Depth模型.将MLP_Depth模型预测水深与160679个检核点处实测水深对比,其差值的标准差STD(75.38 m)、平均绝对百分比误差MAPE(5.89%)与平均绝对误差MAE(42.91 m)皆优于GEBCO_2021模型、topo_23.1模型、ETOPO1模型与检核点实测水深差值的STD(108.88 m、113.41 m、229.67 m)、MAPE(6.11%、6.94%、18.37%)与MAE(47.33 m、52.24 m、130.08 m).同时,为了研究不同区域内利用该方法建立的海底地形模型的精度,本文在研究区域内分别建立了A、B区域的海底地形模型(MLP_Depth_A、MLP_Depth_B).经过验证得:MLP_Depth_A、MLP_Depth_B相比于MLP_Depth模型具有更高的精度,更能反应海底地形的变化趋势. 展开更多
关键词 多层感知机 海底地形 南海 垂线偏差 重力异常 垂直重力梯度
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重力数据探测地下目标的贝叶斯方法研究
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作者 黄佳喜 边少锋 纪兵 《大地测量与地球动力学》 CSCD 北大核心 2024年第2期154-159,176,共7页
针对地下目标空间位置和形状均未知的情况,基于重力数据,分别以区域测量和线测量2种场景进行建模分析,研究贝叶斯推断用于地下目标探测的效果。结果表明,将贝叶斯推断用于重力梯度探测,比微重力探测更具优势,能有效反演出目标的未知参数。
关键词 地下目标探测 重力异常 重力梯度 贝叶斯推断 最高密度区间
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重力场模型在水利工程测量中的应用研究
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作者 郭勇 《科技创新与应用》 2024年第33期183-186,共4页
该研究旨在通过数据采集与处理、数学表达与参数确定等步骤,探讨水利工程正常高测量中重力场模型的建模与应用,研究介绍水利工程中重力场模型的基本概念、分类及其重要性,构建精确的模型。在应用方面,研究通过案例分析对重力场模型的有... 该研究旨在通过数据采集与处理、数学表达与参数确定等步骤,探讨水利工程正常高测量中重力场模型的建模与应用,研究介绍水利工程中重力场模型的基本概念、分类及其重要性,构建精确的模型。在应用方面,研究通过案例分析对重力场模型的有效性进行详细的阐述,在正常高测量中对重力场模型进行具体的测量。研究还就大坝变形监测、河道水库水位监测、管网系统压力监测中重力场模型的具体应用进行讨论,提出模型精度优化、改进数据处理技术、集成实时监控预警系统等方面的技术优化措施。研究结果显示,在提高水利工程测量精度和安全管理方面,重力场模型的作用十分显著。 展开更多
关键词 重力场模型 水利工程 正常高测量 大坝变形监测 重力梯度
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基于重磁场年变化联合分析马尔康M_(S)6.0地震特性
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作者 刘东 赵育飞 +2 位作者 张勇 黄江培 吴宇琴 《地震科学进展》 2024年第11期820-830,共11页
利用川西地区2017—2021年多期地面重力观测和地磁观测资料,对马尔康MS6.0地震进行分析,并使用重磁场年变归一化融合分析结果对地震的发震位置进行分析,获得了融合分析结果和马尔康地震要素之间的相关关系。结果表明:区域重力场异常变... 利用川西地区2017—2021年多期地面重力观测和地磁观测资料,对马尔康MS6.0地震进行分析,并使用重磁场年变归一化融合分析结果对地震的发震位置进行分析,获得了融合分析结果和马尔康地震要素之间的相关关系。结果表明:区域重力场异常变化与川西地区断裂带在空间上关系密切,马尔康震中地区重力场变化较为微弱,变化量等值线始终在零值线左右,但在周边地区变化剧烈;岩石圈磁场年变化结果显示,震前岩石圈磁场水平矢量从区域整体弱变,到震中持续弱变和外围整体趋同后反向弱变,弱变量级较小且方向散乱;融合归一化震前一年期重磁场年变化数据,根据核密度曲线的重叠范围和峰值差较小的条件,可以判定出强震发震的区间范围(30°N~33°N,101°E~104°E),2022年6月芦山M_(S)6.1和马尔康M_(S)6.0地震就发生在该区间范围内。进一步将川西地区按1°×1°的格网划分后,马尔康地区重磁变化核密度曲线峰值差逐年减小,并在发震前重力变化和地磁变化峰值差达到最小。马尔康地区重力场和岩石圈磁场的磁化率变化在孕震过程中逐年趋于一致,证明了区域内存在物质和能量的交换和动力作用,引起了活动断层物质变迁和构造变形,在地表产生了相应的重力变化和岩石圈内磁场变化。重磁场的年变融合分析对强震发震位置的判定具有一定的指导意义。 展开更多
关键词 重力异常 归一化 核密度曲线 岩石圈磁场总强度
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