小卫星数据的变化监测能力分析     

李静  党福星  李志忠 《测绘科学》2009,34(3)

为了促进小卫星数据在地质灾害监测中的应用与推广,本文以监测采矿图斑变化为目标,通过对北京地区的2006年和2007年两期北京一号小卫星4m全色影像采用正射校正、配准和迭加对比的方法发现变化信息。结合1∶50 000影像图、野外调查和测量,确定变化图斑的边界、变化原因和规模,并对小卫星全色图像的变化监测能力进行分析和总结。本文通过对小卫星4m全色影像数据的分析,基本上可以概括出其变化监测能力。  相似文献   

东秦岭回龙湾强应变带及其地质意义     

李荣玺  鹿粗  胡能高 《河南国土资源》1999,(1)

东秦岭二郎坪群和石界河群之间发现了一条强应变带（称之为回龙湾强应变带）,呈ＮＮＷ—ＳＳＥ向延伸,面理置换强烈,韧性剪切变形特征明显,糜棱岩发育。该强应变带的发现表明,二郎坪群和石界河群之间既非不整合接触,也不是整合接触,而是断层接触关系。结合原岩建造、沉积环境和变质作用特征,作者认为二郎坪群和石界河群之间并非简单的地层学上的上下关系,而是两个近乎同时异地的变质地质体。  相似文献   

秦皇岛近岸海域夏季小型水母分布特征     

徐东会  齐衍萍  张炫钊  杜小媛  韩龙江  刘潇  周辉  潘玉龙 《海洋科学》2022,46(11):29-37

本研究基于2014—2018年每年8月份,于秦皇岛海域使用浅水Ⅰ型浮游生物网采集的浮游动物样品数据,分析了小型水母群落的组成种类和丰度分布特征及环境因子与水母群落特征之间的关系。结果如下:2014—2018年调查海域共出现小型水母13种,其中2014、2015和2017年夏季水母种类数均为7种, 2016年夏季水母种类数为6种, 2018年夏季水母种类数最少,仅为2种。秦皇岛近岸水域水母的优势种包括薮枝螅水母、球型侧腕水母和锡兰和平水母。2016年夏季秦皇岛水域水母丰度的平均值最高,达到了95.0 ind./m3。2014、2015和2018年分别为66.9 ind./m³、69.1 ind./m³和35.4 ind./m³。2017年最低,为14.9 ind./m³。通过小型水母丰度与环境因子之间的相关性分析,结果显示:温度、盐度、pH、磷酸盐、溶解氧、无机氮、悬浮物等环境因子会对秦皇岛夏季水域水母群落结构的年际间变化产生显著影响。  相似文献   

波形差异反演方法及其在气藏描述中的应用   总被引：3，自引：3，他引：0       下载免费PDF全文

苏小军  管仁顺  王利田  段林娣  孙新销 《地球物理学进展》2007,22(5):1578-1584

在油气藏开发中后期,如何利用的已有的勘探成果和丰富的油气藏知识,加深对勘探区域油气开发潜力的认识,为油气田的稳产高产服务,是摆在油气田中后期开发人员面前的难题.油气田开发的研究人员,利用现有的资料,开发出了很多方法,结合地震测井等资料为油气田的稳产高产做出了巨大的贡献.本文在分析了地震波在地质体中传播过程中能量变化,相应的产生了振幅变化的理论,利用三维地震数据,通过对三维地震数据解释层位对应的波形差异的分析,结合工区内的生产井和开发井的对应地层中的油气信息,进行反演得到地层的波形差异数据体,利用相应的绘图软件绘制二维平面图形,结合工区内的沉积相等地质信息对其数据体进行油藏解释,最终得到波形差异反演数据体,利用波形差异反演数据体进行油气藏的识别、描述和预测,为油气田的中后期开发服务.  相似文献   

旋转椭球面上的应变与转动张量表达   总被引：6，自引：1，他引：5       下载免费PDF全文

刘序俨  黄声明  梁全强 《地震学报》2007,29(3):240-249

以旋转椭球体面上某点为原点建立一个大地坐标单位活动坐标架. 通过平移, 使活动坐标架的原点与以椭球中心为原点的笛卡尔单位标架的原点相重合. 然后再通过两次标架旋转, 使活动坐标架与笛卡尔单位标架完全重合. 本文给出了使两个单位标架相重合的转换关系式, 以及该点位移在两个单位标架中的坐标转换式; 在此基础上, 考虑该点的位移及活动坐标架皆为该点大地坐标的函数, 经复杂推导, 分别给出了该点位移向量的微分在大地坐标系中的分量以及该点分别沿坐标曲线的弧微分表达式, 继而导出了该点的位移梯度矩阵; 最后推导出了椭球坐标系的应变张量与转动张量表达式, 并对转动张量的几何含义进行了较详细的解释, 且采用曲面理论对球面与椭球面的应变张量间的内在关系进行了讨论.   相似文献   

板内与板间地震活动时空分布的多重分形特征研究          下载免费PDF全文

陈时军  孙龙梅  马丽 《地震学报》2007,29(1):38-47

利用多重分形分析方法,考察了中国大陆和台湾地区以及新西兰的地震活动广义应变释放时间和空间分布的多重分形特征. 结果表明,地震活动时空分布的多重分形特征与不同地球动力学环境关系密切. 强震活动时间分布在板间地区具有比板内地区更明显的丛集性, 对中小地震这种丛集性差异较小;强震活动空间分布在板内地区具有比板间地区更强的丛集性,但对中小地震则相反.   相似文献   

近期流域沙量平衡计算研究进展     

蔡强国  崔明  范昊明 《地理科学进展》2007,26(2):52-58

沙量平衡计算是一种探讨侵蚀泥沙从坡面、沟道等处侵蚀起到流域出口输出这一复杂过 程十分有效的研究方法, 该方法将流域内泥沙的侵蚀、输移、沉积和输出等过程进行综合考虑, 既 打破了流域泥沙研究的破碎性, 也可以有效地评价泥沙输移系统的有效性。近期国外泥沙平衡计 算研究在研究方法上有了很大的改进和提高, 对其进行总结和评价将有助于我国沙量平衡研究 的开展, 从而为流域水沙管理提供一个有效的方法和手段。  相似文献   

The strain‐dependent spatial evolution of garnet in a high‐P ductile shear zone from the Western Gneiss Region (Norway): a synchrotron X‐ray microtomography study          下载免费PDF全文

A. Macente  F. Fusseis  L. Menegon  X. Xiao  T. John 《Journal of Metamorphic Geology》2017,35(5):565-583

Reaction and deformation microfabrics provide key information to understand the thermodynamic and kinetic controls of tectono‐metamorphic processes, however, they are usually analysed in two dimensions, omitting important information regarding the third spatial dimension. We applied synchrotron‐based X‐ray microtomography to document the evolution of a pristine olivine gabbro into a deformed omphacite–garnet eclogite in four dimensions, where the 4^th dimension is represented by the degree of strain. In the investigated samples, which cover a strain gradient into a shear zone from the Western Gneiss Region (Norway), we focused on the spatial transformation of garnet coronas into elongated garnet clusters with increasing strain. The microtomographic data allowed quantification of garnet volume, shape and spatial arrangement evolution with increasing strain. The microtomographic observations were combined with light microscope and backscatter electron images as well as electron microprobe (EMPA) and electron backscatter diffraction (EBSD) analysis to correlate mineral composition and orientation data with the X‐ray absorption signal of the same mineral grains. With increasing deformation, the garnet volume almost triples. In the low‐strain domain, garnet grains form a well interconnected large garnet aggregate that develops throughout the entire sample. We also observed that garnet coronas in the gabbros never completely encapsulate olivine grains. In the most highly deformed eclogites, the oblate shapes of garnet clusters reflect a deformational origin of the microfabrics. We interpret the aligned garnet aggregates to direct synkinematic fluid flow, and consequently influence the transport of dissolved chemical components. EBSD analyses reveal that garnet shows a near‐random crystal preferred orientation that testifies no evidence for crystal plasticity. There is, however evidence for minor fracturing, neo‐nucleation and overgrowth. Microprobe chemical analysis revealed that garnet compositions progressively equilibrate to eclogite facies, becoming more almandine‐rich. We interpret these observations as pointing to a mechanical disintegration of the garnet coronas during strain localization, and their rearrangement into individual garnet clusters through a combination of garnet coalescence and overgrowth while the rock was deforming.  相似文献   

Dynamics of unsaturated poroelastic solids at finite strain     

Ryosuke Uzuoka  Ronaldo I. Borja 《国际地质力学数值与分析法杂志》2012,36(13):1535-1573

We derive the governing equations for the dynamic response of unsaturated poroelastic solids at finite strain. We obtain simplified governing equations from the complete coupled formulation by neglecting the material time derivative of the relative velocities and the advection terms of the pore fluids relative to the solid skeleton, leading to a so‐called u^s ? p^w ? p^a formulation. We impose the weak forms of the momentum and mass balance equations at the current configuration and implement the framework numerically using a mixed finite element formulation. We verify the proposed method through comparison with analytical solutions and experiments of quasi‐static processes. We use a neo‐Hookean hyperelastic constitutive model for the solid matrix and demonstrate, through numerical examples, the impact of large deformation on the dynamic response of unsaturated poroelastic solids under a variety of loading conditions. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Estimating the crush zone size under a cutting tool in coal     

R. K. Zipf Jr.  Z. T. Bieniawski 《Geotechnical and Geological Engineering》1988,6(4):279-295

Summary As part of an effort to understand the mechanics of fine fragment formation in coal, which is important in studies of respirable dust due to mining, fracture toughness measurements and the strain energy density (SED) theory were applied to calculate the crush zone size under a cutting tool in coal. This zone is the major source of fine fragments in the 1 to 10 µm size range. The model used in these calculations is a boundary element program containing a failure criterion based on the SED theory. The boundary element program calculates linear elastic stresses at numerous points in the coal material ahead of a cutting bit. These stresses are then input to a subroutine called critical flaw length and orientation (CFLO) which uses the SED theory to determine the CFLO for a small crack at the boundary element stress computation point. The extent of crushing is based on earlier postulates about the role of inherent flaws in a fragmentation process. To form 1 to 10 µm fragments requires firstly a local stress strong enough to activate flaws with a characteristic length less than 1 to 10 µm and secondly, a flaw density sufficient to provide an average spacing between flaws also on the order of 1 to 10 µm. The locus of active 10 µm flaws represents the maximum possible extent of fine fragmentation in the 10 µm or less size range assuming that a sufficient inherent flaw density exists. The approach offers a first order approximation to the extent of crushing under a tool tip. The size and shape of the crush zone volume is affected by the attack angle and geometry of the tool.  相似文献