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福建地区地块运动时空变化特征研究 被引量:9
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作者 丁学仁 胡新康 刘序俨 《大地测量与地球动力学》 CSCD 北大核心 2006年第2期58-61,共4页
为了研究福建地区活动地块边界带的运动及块体内部变形规律,利用5期GPS观测资料(1995、1997、1999、2001、2003年)计算了福建块体的趋势性差异运动年变速率、优势水平运动年速率,以及在区域无整体旋转基准下各GPS测点运动速率。GPS网5... 为了研究福建地区活动地块边界带的运动及块体内部变形规律,利用5期GPS观测资料(1995、1997、1999、2001、2003年)计算了福建块体的趋势性差异运动年变速率、优势水平运动年速率,以及在区域无整体旋转基准下各GPS测点运动速率。GPS网5期观测的不同测点速率随时间序列变化结果显示福建活动块体整体向东南方向运动,而块体内部形变量较小(约1mm/a)。 展开更多
关键词 块体运动 GPS 年变速率 边界带运动 福建地区
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地球表层运动和变形的GPS描述 被引量:7
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作者 黄立人 郭良迁 《地学前缘》 EI CAS CSCD 2003年第U08期17-21,共5页
利用IERS所公布的分在全球各大构造板块上的 6 5 7个GPS、SLR和VLBI连续观测站在ITRF框架下的速度场资料 ,采用刚体板块运动 +板块整体均匀应变 +板块内局部不均匀应变的变形分析模型 ,研究了全球各主要板块的运动和变形。结果表明板... 利用IERS所公布的分在全球各大构造板块上的 6 5 7个GPS、SLR和VLBI连续观测站在ITRF框架下的速度场资料 ,采用刚体板块运动 +板块整体均匀应变 +板块内局部不均匀应变的变形分析模型 ,研究了全球各主要板块的运动和变形。结果表明板块的整体变形在统计上均不显著。在一级近似上板块间表现出来的整体相对运动显著 ,根据这些运动参数定量研究了板块边界的相对运动的大小和性质。认为地球的双重不对称变形可能主要表现为南北、东西两半球所含的板块边界的运动方式不同所致。板块内的局部不均匀变形明显 ,为板块内部可能应划分成次一级的活动地块提供了佐证。由于观测点分布的密度和均匀性不足 ,本文未能就板内不均匀变形作进一步的深入讨论。 展开更多
关键词 GPS速度场 板块运动 ITRF2000 变形 板块边界带
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A Kinematic Thermal Model for Descending Slabs with Velocity Boundary Layers:A Case Study for the Tonga Subducting Slab 被引量:2
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作者 ZHANG Keliang WEI Dongping 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2011年第1期211-222,共12页
For the purpose of investigating the influence of metastable olivine(MO) phase transformations on both deep seismicity and stagnation of slabs,we constructed a 2-dimensional finite element thermal model for a 120 Ma... For the purpose of investigating the influence of metastable olivine(MO) phase transformations on both deep seismicity and stagnation of slabs,we constructed a 2-dimensional finite element thermal model for a 120 Ma-old 50°dipping oceanic lithosphere descending at 10 cm/yr with velocity boundary layers,which would mitigate the interference of constant velocity field for the slab. The resulting temperatures show that most of intermediate and deep earthquakes occurring within the Tonga slab are occurring inside the 800℃and 1200℃isotherm,respectively.The elevation of olivine transformation near~410 km and respective persistence of metastable olivine and spinel within the transition zone and beneath 660 km would thus result in bimodal positive,zonal,negative density anomalies,respectively.These results together with the resulting pressure anomalies may reflect the stress pattern of the Tonga slab:(i) slab pull force exerts above a depth of~230 km;(ii) MO existence changes the buoyancy force within the transition zone and facilitates slab stagnation at a depth of 660 km;(iii) as the subducting materials accumulated over 660 km,deepest earthquakes occur due to MO transformation;(iv) a flattened‘slab’ may penetrate into the lower mantle due to the density increment of Sp transformation. 展开更多
关键词 kinematic thermal model subduction zone velocity boundary layer metastable olivine double seismic zone finite element method
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A Kinematic Thermal Model for Descending Slabs with Velocity Boundary Layers
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作者 Keliang Zhang Graduate University of the Chinese Academy of Sciences,College of Earth Science,Beijing 100049,China. 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期195-196,共2页
Kinematic models compute the temperature distribution by prescribing a constant convergent velocity for the subducting slab,resulting in an artificial velocity discontinuity,which may accelerate the heating of subduct... Kinematic models compute the temperature distribution by prescribing a constant convergent velocity for the subducting slab,resulting in an artificial velocity discontinuity,which may accelerate the heating of subducting slabs.For the purpose to moderate the influence of such artificial discontinuity, we construct a 2D thermal model for subduction zones with a velocity boundary layer,within which the velocities decrease linearly with the distance from the interfaces of slabs.Temperatures are calculated 展开更多
关键词 KINEMATIC model thermal structure SUBDUCTION zone velocity boundary layer finite element method
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2011—2014年康定周边地形变场变化与芦山7.0级地震及康定两次中强地震的关系研究 被引量:1
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作者 夏峰 郭良迁 《地震工程学报》 CSCD 北大核心 2017年第4期686-691,共6页
收集康定地震区及周边(99.6°~105.2°E,27.8°~33.0°N范围内)连续GPS观测站的资料求解站速度场,采用刚性-线弹性运动方程计算方法,拟合计算得到研究区域规格网格点(0.4°×0.4°)的速度值和主应变率值。... 收集康定地震区及周边(99.6°~105.2°E,27.8°~33.0°N范围内)连续GPS观测站的资料求解站速度场,采用刚性-线弹性运动方程计算方法,拟合计算得到研究区域规格网格点(0.4°×0.4°)的速度值和主应变率值。基于该结果分析研究区内的运动特征和应变场变化情况,并讨论其与地震孕育发生的关系。分析结果表明,芦山7.0级地震发生前研究区呈现应变能量积累态势,而地震之后研究区呈应变能量释放调整态势,2014年康定地震的发生就是该区构造运动调整下的产物。 展开更多
关键词 康定地震 水平运动场 主应变率场 速度分界带
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A Laboratory Study of the Turbulent Velocity Characteristics in the Convective Boundary Layer 被引量:2
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作者 孙鉴泞 蒋维楣 +1 位作者 陈子贇 袁仁民 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2005年第5期770-780,共11页
Based on the measurement of the velocity field in the convective boundary layer (CBL) in a convection water tank with the particle image velocimetry (PIV) technique, this paper studies the characteristics of the C... Based on the measurement of the velocity field in the convective boundary layer (CBL) in a convection water tank with the particle image velocimetry (PIV) technique, this paper studies the characteristics of the CBL turbulent velocity in a modified convection tank. The experiment results show that the velocity distribution in the mixed layer clearly possesses the characteristics of the CBL thermals, and the turbulent eddies can be seen obviously. The comparison of the vertical distribution of the turbulent velocity variables indicates that the modeling in the new tank is better than in the old one. The experiment data show that the thermal's motion in the entrainment zone sometimes fluctuates obviously due to the intermittence of turbulence. Analyses show that this fluctuation can influence the agreement of the measurement data with the parameterization scheme, in which the convective Richardson number is used to characterize the entrainment zone depth. The normalized square velocity wi^2/w*^2. at the top of the mixed layer seems to be time-dependent, and has a decreasing trend during the experiments. This implies that the vertical turbulent velocity at the top of the mixed layer may not be proportional to the convective velocity (w*). 展开更多
关键词 convective boundary layer (CBL) convection water tank turbulent velocity entrainment zone
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