检索结果-南通市图书馆

Structure of the mantle transition zone in the central and western parts of the North China Craton using the receiver function 3D Kirchhoff migration method

引用

Science China Earth Sciences 2024年第9期67卷 2783-2795页

作者： Min ZHU Qingju WU Jieyuan NING Ruiqing ZHANG institute of geophysics China Earthquake AdministrationBeijing 100081China institute of Theoretical and applied geophysics Peking UniversityBeijing 100871China

Using data from the regional broadband dense temporary array deployed by the ChinArray project,we applied the three-dimensional(3D)Kirchhoff migration method of the teleseismic P-wave receiver function to investigate discontinuity structures of the mantle transition zone(MTZ)in the central and western parts of the North China Craton(NCC)using a highresolution 3D velocity model of the East Asian *** results show that the 410-km discontinuity beneath the Datong Volcano is depressed by~10 km,indicating the presence of a high-temperature anomaly near the depth of 410 km,which is likely related to small-scale mantle upwelling caused by the dehydration of the stagnant Pacific Plate in the *** upwelling of hot material provides a heat source for surface magmatic *** the Bohai Bay Basin,significant subsidence of the 660-km discontinuity is observed,and the transition zone here is extensively ***’s suggested that the anomalies in this region are related to the stagnation of the Pacific slab in the *** the thickness of the transition zone west of the North-South Gravity Lineament appears normal,we propose that the subducting front of the Pacific slab did not cross the gravity lineament in the *** comparison,the small-scale subsidence of the 660-km discontinuity and the thickening of the MTZ observed north of the Hannuoba Volcano likely indicate that the slab crossed the gravity lineament at its turning point and remained in the ***,a local thickening of the MTZ is observed in the Dabie orogenic belt of the Qinling *** is believed to be a combined effect of lithospheric delamination into the transition zone in the lower Yangtze region and the stagnation of the Pacific Plate.

关键词： North China Craton Mantle transition zone Receiver function migration Datong Volcano

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

THE HP-VERSION OF BEM-FAST CONVERGENCE,ADAPTIVITY AND EFFICIENT PRECONDITIONING

引用

Journal of Computational Mathematics 2009年第2期27卷 348-359页

作者： Ernst P.Stephan institute of applied Mathematics Leibniz University HannoverGermany

In this survey paper we report on recent developments of the hp-version of the boundary element method （BEM）. As model problems we consider weakly singular and hypersingular integral equations of the first kind on a planar, open surface. We show that the Galerkin solutions （computed with the hp-version on geometric meshes） converge exponentially fast towards the exact solutions of the integral equations. An hp-adaptive algorithm is given and the implementation of the hp-version BEM is discussed together with the choice of efficient preconditioners for the ill-conditioned boundary element stiffness matrices. We also comment on the use of the hp-version BEM for solving Signorini contact problems in linear elasticity where the contact conditions are enforced only on the discrete set of Gauss-Lobatto points. Numerical results are presented which underline the theoretical results.

关键词： hp-version of the boundary element method Adaptive refinement Preconditioning Signorini contact

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Estimation of petrophysical parameters using seismic inversion and neural network modeling in Upper Assam basin, India

引用

Geoscience Frontiers 2019年第3期10卷 1113-1124页

作者： Triveni Gogoi Rima Chatterjee Department of applied geophysics Indian Institute of Technology (Indian School of Mines)

Estimation of petrophysical parameters is an important issue of any reservoirs. Porosity, volume of shale and water saturation has been evaluated for reservoirs of Upper Assam basin, located in northeastern India from well log and seismic data. Absolute acoustic impedance(AAI) and relative acoustic impedance(RAI) are generated from model based inversion of 2-D post-stack seismic data. The top of geological formation, sand reservoirs, shale layers and discontinuities at faults are detected in RAI section under the study area. Tipam Sandstone(TS) and Barail Arenaceous Sandstone(BAS) are the main reservoirs,delineated from the logs of available wells and RAI section. Porosity section is obtained using porosity wavelet and porosity reflectivity from post-stack seismic data. Two multilayered feed forward neural network(MLFN) models are created with inputs: AAI, porosity, density and shear impedance and outputs: volume of shale and water saturation with single hidden layer. The estimated average porosity in TS and BAS reservoir varies from 30% to 36% and 18% to 30% respectively. The volume of shale and water saturation ranges from 10% to 30% and 20% to 60% in TS reservoir and 28% to 30% and 23% to 55% in BAS reservoir respectively.

关键词： Upper Assam basin Relative acoustic impedance Porosity Volume of shale Water saturation Neural network model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Improvements in Inversion of Magnetic Resonance Exploration-Water Content, Decay Time, and Resistivity

引用

Journal of China University of Geosciences 2009年第3期20卷 592-605页

作者： Ugur Yaramanci Mike Müller-Petke leibniz institute of applied geophysics Stilleweg 2 Hannover D-30655 Germany Berlin University of Technology Ackerstrasse 71-76 Berlin D-13355 Germany

In this review article, we present recent developments and improvements in magnetic resonance sounding （MRS）, a newly established geophysical exploration method that provides unique information about hydrogeophysical properties due to its direct sensitivity to hydrogen protons and proton dynamics. Starting with the most sophisticated and complete MRS formulation, we give a detailed view on how to solve the equation, i.e., inverting exactly for all model parameters： water content, decay time, and resistivity. Giving a short review of general inversion schemes used in geophysics, the special properties of MRS inversion are evaluated and the development of MRS inversion over recent years is shown. We present the extension of MRS to magnetic resonance tomography （MRT）, i.e., the extension to two-dimensional investigations and appropriate inversions. Finally, we address restrictions, limitations, and inconsistencies as well as future developments.

关键词： magnetic resonance sounding (MRS) magnetic resonance tomography (MRT) inversion modeling water content decay time resistivity.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Myanmar-Andaman-Sumatra Subduction Margin Revisited:Insights of Arc-Specific Deformations

引用

Journal of Earth Science 2017年第4期28卷 683-694页

作者： Prosanta Kumar Khan Sk Shamim Manoranjan Mohanty Prabhat Kumar Jayashree Banerjee Department of applied geophysics Indian Institute of Technology(ISM)Dhanbad 826 004India

We address the role of the concave and convex arcs （as observed from the subducting plate） on the deformation occurring along the Myanmar-Andaman-Sumatra margin. We categorize the pre- and post-seismic deformations of the lithosphere using earthquake database occurring either prior to 26th December 2004 Mw 9.3 off-Sumatra mega-event or after the incidence. Analysis under pre-seismic domain shows that area near Sumatra records highest seismicity, which largely drops in the area past the North Andaman, and further increases towards north. Shallowest depth and mini- mum dip of the subducting lithosphere is recorded at the central segment where the arc transformed into concave shape. The annual moment energy release during earthquake decreases to more than two orders of magnitude past the North Andaman towards north under post-seismic deformation phase. Higher depths of continuity of events are presumably associated with more dipping Benioff zones in both the Indo-Myanmar and Andaman-Nicobar convex arcs. These observations obviously account for tectonic subdivision of the margin near concave shape arc around the central part. Absence of vol- canism, presence of splay faults in the back-arc, sharp reduction in seismicity near central segment are interpreted to be caused by major tectonic impact of the NNE-ward converging buoyant Ninety-east Ridge against the Asian Plate. Shallowest dip, small elastic thickness, weak converging Indian litho- sphere, and evidences of series of en-echelon blocks off the eastern side of the broken northern Ninety- east Ridge might be incapable of generating great earthquake in this area.

关键词： Myanmar-Andaman-Sumatra margin double arc Ninety-east Ridge buoyancy.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Geometries, stabilities, and electronic properties analysis in In_nNi^((0,±1)) clusters: Molecular modeling and DFT calculations

引用

Chinese Physics B 2017年第8期26卷 130-139页

作者：史顺平张传瑜赵晓凤李侠闫珉蒋刚 Department of applied Physics College of Geophysics Chengdu University of Technology institute of Atomic and Molecular Physics Sichuan University

Density functional theory（DFT） with the B3 LYP method and the SDD basis set is selected to investigate In_nNi,In_nNi^-, and In_nNi~＋（n = 1–14） clusters. For neutral and charged systems, several isomers and different multiplicities are studied with the aim to confirm the most stable structures. The structural evolution of neutral, cationic, and anionic In_nNi clusters, which favors the three-dimensional structures for n = 3–14. The main configurations of the In_nNi isomers are not affected by adding or removing an electron, the order of their stabilities is also nearly not affected. The obtained binding energy exhibits that the Ni-doped In_（13） cluster is the most stable species of all different sized clusters. The calculated fragmentation energy and the second-order energy difference as a function of the cluster size exhibit a pronounced even–odd alternation phenomenon. The electronic properties including energy gap（E_g）, adiabatic electron affinity（AEA）, vertical electron detachment energy（VDE）, adiabatic ionization potential energy（AIP）, and vertical ionization potential energy（VIP） are studied. The total magnetic moments show that the different magnetic moments depend on the number of the In atoms for charged In_nNi. Additionally, the natural population analysis of In_nNi^（（0,±1）clusters is also discussed.

关键词： InnNi(0,±1) clusters stability electronic property density functional theory

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Recent behavior and possible future evolution of the glacieret in the cirque Golemiya Kazan in the Pirin Mountains under conditions of climate warming

引用

Journal of Mountain Science 2019年第1期16卷 16-29页

作者： Peter NOJAROV Emil GACHEV Karsten GRUNEWALD National institute of geophysics Geodesy and Geography Bulgarian Academy of Sciences South-West University "Neofit Rilski" leibniz institute of Ecological Urban and Regional Development

This research reveals relationships between climate variables and inter-annual dynamics in the area of the glacieret located in the cirque Golemiya Kazan in the Pirin Mountains. The study period is 1993–2017. The correlations are identified using statistical methods. Also, a statistical model is constructed, including some climate variables as predictors. Despite the evident decrease of the glacieret's size in the period from the 1950 s onwards, the long-term trends for the last decades have been insignificant. The main climatic factors influencing the inter-annual dynamics in the area of the glacieret are air temperature, precipitation, zonal and meridional winds and relative humidity. With respect to the dynamics in the area of the glacieret, the important trends in the different climate variables are those of the warm period air temperatures and zonal(u) wind. They also determine to a great extent its future development by acting in two opposite directions – rising temperatures in the warm period will lead to a rapid decrease of its area by the end of the melting season, while the change of wind directionfrom west to east in the warm period will increase its area. The influence of the zonal wind in the warm period is explained mainly by the location of the glacieret in the cirque. Generally, the glacieret is tilted downwards from west to east. Thus, westerly winds facilitate blowing away the snow from the surface of the glacieret, assisting its melting in the warm period. Easterly winds do not have such an effect. The combination of the opposite effects of these two most important climate variables leads to the most likely scenario for the future development of the glacieret, according to which by the middle of this century it is expected to turn into a semi-permanent snow patch, which disappears after some summers, and by the end of the century to completely melt every year before the end of the melting season.

关键词： Climate warming Glacieret Pirin Mountains Statistical modeling Glacieret area Projection

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Capture the variation of the pore pressure with different geological age from seismic inversion study in the Jaisalmer sub-basin,India

引用

Petroleum Science 2020年第6期17卷 1556-1578页

作者： Raman Chahal Saurabh Datta Gupta Department of applied geophysics Indian Institute of Technology(Indian School of Mines)DhanbadDhanbadJharkhand 826004India

Geoscientific evidence shows that various parameters such as compaction,buoyancy effect,hydrocarbon maturation,gas effect and tectonic activities control the pore pressure of sub-surface *** controlled geoscientific data in the tectonically active areas is significantly useful for robust estimation of pre-drill pore *** reservoir which is tectonically complex and pore pressure is changing frequently that circumference motivated us to conduct this *** changes in pore pressure have been captured from the fine-scale to the broad scale in the Jaisalmer *** pressure variation has been distinctly observed in pre-and post-Jurassic age based on the current ***-stack seismic inversion study was conducted to capturing the variation of pore *** of low-frequency spectrum and integrated interval velocity model provided a detailed feature of pore pressure in each compartment of the study *** pressure estimated from well log data was correlated with seismic inversion based *** on the current study one well has been proposed where pore pressure was estimated and two distinguished trends are identified in the study *** approaches of the current study were analysed thoroughly and it will be highly useful in complex reservoir condition where pore pressure varies frequently.

关键词： Pore pressure Seismic inversion Clastic and carbonate reservoir

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Advanced surface coil layout with intrinsic noise cancellation properties for surface-NMR applications

引用

Magnetic Resonance Letters 2023年第2期3卷 140-149,I0004页

作者： Thomas Hiller Stephan Costabel Raphael Dlugosch Tobias Splith Mike Müller-Petke Federal institute for Geosciences and Natural Resources Wilhelmstr.25-30Berlin13595Germany Federal institute for Geosciences and Natural Resources Stilleweg 2Hannover3655Germany leibniz institute for applied geophysics Stilleweg 2Hannover30655Germany

A recent study demonstrated that in small-scale prepolarized surface nuclear magnetic resonance(SNMR-PP)measurements with a footprint of a few square meters,customized PP switch-off ramps can serve as an efficient excitation mechanism,eliminating the requirement for a conventional oscillating excitation *** approach enables the detection of short relaxation signals from the unsaturated soil zone and can,therefore,be used to directly provide soil moisture and pore geometry *** ultimately such small-scale SNMR-PP setups are intended for a mobile application,it is necessary to develop strategies that allow for speedy measurement progress and do not require noise cancellation protocols based on reference ***,we developed a new concentric figure-of-eight(cFOE)loop layout that combines the direction independence of a circular loop with the intrinsic noise cancellation properties of a classical *** approach significantly decreases the measurement time because suitable signal-to-noise ratios are reached much faster compared to a classical circular loop and will bring us one step further toward fast and non-invasive soil moisture mapping applications.

关键词： Surface-NMR Prepolarization Noise cancellation Loop layout

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Geophysical evidence of a large occurrence of mud volcanoes associated with gas plumbing system in the Ross Sea(Antarctica)

引用

Geoscience Frontiers 2024年第1期15卷 304-324页

作者： Martina Busetti Riccardo Geletti Dario Civile Chiara Sauli Giuseppe Brancatelli Edy Forlin Daniela Accettella Lorenza Barro Savonuzzi Laura De Santis Aldo Vesnaver Andrea Cova National institute of Oceanography and applied geophysics–OGS Borgo Grotta Gigante 42/c34010 SgonicoTriesteItaly

Seafloor and buried reliefs occur along continental margin of the Ross Sea(Antarctica).These features are several kilometres wide and tens of metres high,exhibiting cone or flat-top dome *** studies have proposed a volcanic or glacial origin for these formations,but these hypotheses do not account for all the available *** this study,we use morpho-bathymetric data,intermediate resolution multichannel seismic and high resolution chirp profiles,as well as magnetic lines to investigate these clusters of *** employing targeted processing techniques to enhance the geophysical characterization of the seafloor and buried reliefs,and to understand the underlying geological features,we propose that the reliefs are mud *** of these formations appear to be associated with a plumbing system,as indicated by acoustic anomalies linked to sediment containing *** formations are likely fed by clayey source rocks of Miocene ***,other reliefs might be the result of mud mobilisation caused by gravity instability and fluid overpressure.

关键词： Ross Sea Antarctica Mud volcanoes Gas plumbing system Gas hydrate Bottom Simulating Reflector

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：