共查询到20条相似文献，搜索用时 218 毫秒
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基于IGRF的地磁基准图技术 总被引：1，自引：0，他引：1
地磁导航需要获得目标区域的地磁基准图。研究了基于国际地磁参考场的地磁场要素计算和等值线绘制方法。以给定目标区域的经纬高为输入,计算高阶地磁球谐函数获取地磁矢量并计算地磁场要素,修正了因地球扁率带来的数据差异。采用具有虚节点的移动矩形网格算法来绘制地磁参数等值线,生成目标区域的地磁基准图。采用C#实现了地磁基准图软件,测试表明,获得的地磁等高线数据满足使用要求,等值线精度较高。 相似文献
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Summary The data of borehole resistivity logs were collected, analysed, classified and a contour map of electrical conductance of the sedimentary complex overlying the crystalline basement of the Czech Republic was computer-generated. The map contributes to estimating the distortion fields produced by conductance variations in the surface layer. Information on the basement relief is also obtained from the contour map patterns. 相似文献
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Summary Induction response has been investigated at 57 field stations covering the Bohemian Massif (BM) and the Bruno-Vistulicum (BV),
and at 93 temporary observing sites across the West Carpathians (WCP). Induction response data at 958 localities covering
mainly the Central European area were also collected and analysed. Components of transfer functions (TF), moduli and arguments
of corresponding induction vectors are analyzed for individual profiles. Pseudo-sections of induction parameters at profiles
are used to visualize the period dependence of induction response and computer generated contour maps of TF components define
zones of anomalous induction and their relation to large scale anomalies. Depths of anomalous field source are estimated by
separating variations into internal and external parts. Correlations among induction response characteristics and the results
of other geophysical investigations are discussed. 相似文献
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四川及邻区地壳垂直形变特征与地震的关系 总被引：6，自引：0，他引：6
对四川及邻区五十年代至八十年代的精密水准复测资料进行处理，绘制了四川及邻区的地壳重直形变速率图、垂直形变速率梯度图和垂直形变速率梯度矢量分布图。结合研究区内构造特征，对上述图件进行分析。指出数处呈四象限分布的图像，结合地震活动进行解释，确定了研究区未来的地震危险区。 相似文献
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对2016年10月20日江苏射阳M4.4地震的强震动记录进行初步分析,介绍强震动记录的一些基本特征。与ShakMap小震回归公式的预测数据比较,发现实际观测值总体高于预测值。通过对强震动记录的反应谱分析,认为本次地震对震中区建筑的影响轻微。在地震动等值线图产出过程中,采用数据偏差校正、场地效应及空间插值方法,使地震动等值线图的空间表达更为合理。其等值线图长轴呈北西向,与此次地震的主破裂面方向一致。结合地震现场调查结果,讨论了震中区的烈度分布与仪器烈度。 相似文献
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对滇西地区6个断层形变测量场地的资料进行处理。获取研究区每月的总体运动速率，绘制每月的形变等值线图，求出每幅图的容量维，探讨容量维，形变等值线和总体运动速率在历次地震前的演变特征。 相似文献
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Terracing is an operator that is applied to potential field data to produce regions of constant field amplitude that are separated by sharp boundaries, as an aid to interpretation. When applied to map data, the boundaries are defined by the zero contour of the 2D Laplacian derivative operator. An improved method is described here that defines the boundaries by the zero contour of the profile curvature. This approach gives superior results because the 2D Laplacian operator is composed only of derivatives in the EW and NS directions, while the profile curvature uses the curvature in the 'uphill' direction at each point, whatever that direction may be. The method is demonstrated on gravity data from South Africa. Source code in Matlab format is available from the authors on request. 相似文献
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J.R. Heirtzler P. Cameron P.J. Cook T. Powell H.A. Roeser S. Sukardi J.J. Veevers 《Earth and Planetary Science Letters》1978,41(1):21-31
Eighteen geophysical transects were made in the Argo Abyssal Plain to study the magnetic anomalies, bathymetry and seismic structure. Magnetic anomalies were identified as being the Mesozoic anomalies M-10 to M-25, increasing in age from the Java Trench to the northwest continental shelf of Australia. A new bathymetric map shows that the Argo Abyssal Plain is bounded by the 5600-m contour and reaches a maximum depth of 5730 m against the inshore side of the Exmouth Plateau. Joey Rise was found to limit the Argo Abyssal Plain on the southwest. Continuous seismic profiles, sonobuoy data and seismic data from other cruises permit one to contour the depths to oceanic basement. Numerous diapir-like structures were observed, but their nature and origin is obscure. 相似文献
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通过地电场台址近地表介质电阻率和地电场值计算大地电流,从大地电流场中分离出涡旋电流;根据平面波理论和水平导电层模型,使用地磁暴观测数据在频率域计算地磁感应电场(GIE),由GIE计算地磁暴感应电流(GIC).计算结果与实测值对比分析表明:GIE计算结果与实测地电暴具有很好的相位一致性;GIC涡旋中心相对地电暴涡旋中心存在向SE漂移约3°的现象;磁暴时地磁场Z分量的幅值分布图中极大值区域与涡旋中心重合,可能是GIC涡旋中心偏移的原因.另外,根据电磁感应原理提出的等效环电流模型,在一定程度上解释了涡旋大地电流的形成机制.本项工作可应用于地磁观测与地电观测的相互校正,同时有助于认识地电暴对大地电流分布的影响. 相似文献
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An algorithm for automating the mapping of land components from digital elevation data is described. Land components are areas of relatively uniform slope and aspect and often correspond with ridge crests, shoulders, head slopes, back slopes or foot slopes. Aspect regions, which generally span from stream to ridge, are first identified by generalizing an aspect map derived from digital elevation data. The aspect regions are then split successively into land components by grouping pixels above or below an automatically determined contour of elevation or ‘distance from stream’. The contour approximates a slope break. The land components mapped in this way give a complete polygonization of a hilly landscape and are a reasonable approximation of manually mapped land components. 相似文献
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A. H. KLEYN 《Geophysical Prospecting》1977,25(1):125-140
After the sampling of a reflection time contour map, i.e. after times and time gradients at the grid points of a square sampling grid have been determined, its conversion into true depth contours can be performed by normal incidence ray tracing. At each grid point the spatial orientation of the ray is uniquely defined by a corresponding time gradient vector, whereas its continuation into the subsurface is controlled by Snell's law. For arbitrarily orientated velocity interfaces the 3 – D ray tracing problem can systematically be solved with the aid of vector algebra, by expressing Snell's law as an equation of vector cross products. This allows to set up a computer algorithm for migration of contour maps. Reliable sampling of reflection time contour maps in the presence of faults is essential for the realization of a practical map migration system. A possible solution of the relevant sampling problem requires a special map editing and digitization procedure. Lateral migration shifts cause a translation and distortion of the original sampling grid. On the transformed grid the true positions of faults can be related to their apparent ones on the reflection time contour map. Errors in the time domain correlations or an incorrect velocity distribution or a combination of both these effects may cause migration failures due to total reflection and time deficiencies, or give rise to an anomalous distortion of grid cells, the latter signifying a violation of the maximum convexity condition. Emphasis is placed upon the significance of map migration as an interpretive tool for solving time to depth conversion problems in the presence of severely faulted or salt intruded overburdens. 相似文献
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国际地磁参考场资料在我国得到广泛应用。利用国际地磁参考场资料，我国学者研究了高斯分析、地球磁场模型及其源场可能位置、重磁关系、核幔耦合、地磁场能量、地球非偶极子磁场西向漂移等。在绘制中国地磁等值图中也利用了某些国际地磁参考场资料。 相似文献
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S. T. G. Raghu Kanth Konjengbam Darunkumar Singh Kumar Pallav 《Pure and Applied Geophysics》2009,166(4):641-672
In this article, the spatial variation of ground motion in Imphal City has been estimated by the finite-fault seismological
model coupled with site response analysis. The important seismic sources around Imphal City have been identified from the
fault map and past seismicity data. The rock level acceleration time histories at Imphal City for the 1869 Cachar (Mw 7.5) earthquake and a hypothetical Mw 8.1 event in the Indo-Burma subduction zone have been estimated by a stochastic finite-fault model. Soil investigation data
of 122 boreholes have been collected from several construction projects in Imphal City. Site response analysis has been carried
out and the surface level ground motion has been determined for Imphal City for these two earthquake events. The results are
presented in the form of peak ground acceleration (PGA) contour map. From the present study it has been ascertained that the
maximum amplification for PGA over Imphal City is as high as 2.5. The obtained contour maps can serve as guidelines for identifying
vulnerable areas and disaster mitigation in Imphal City. 相似文献
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Igor M. Logvinov 《Acta Geophysica》2015,63(5):1216-1230
The results of deep induction sounding in Ukraine made in the twenty-first century with the participation of the author have been summarized, including also a number of data obtained in the previous decades. The apparent resistivity and magnetic transfer function on the territories of western Ukraine and eastern Poland have been analyzed. The articulation of these data with the regional magnetic variation soundings allowed taking into account the influence of a static shift of areal interpretation of magnetotelluric resistivity results, which increased the reliability of interpretation. The analysis of induction sounding performed with 1D, 2D, and 3D inversions of magnetic transfer functions allowed localizing the crustal anomalies. The results are discussed. 相似文献
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天津滨海新区潜在淹没区发展趋势研究 总被引：1，自引：0，他引：1
本文利用2006年以前天滓地面沉降监测资料和塘沽、汉沽地区潜在淹没区RTK加密观测资料,以水准监测点为基本研究对象,深入分析研究了每个测点随时间的沉降变化规律,进而“以点带面”绘制了2005年和2011年天津滨海新区地面沉降速率等值线图。同时,还绘制了2005年塘沽、汉沽地区潜在淹没区地面标高等值线分布图,以及预测的2011年塘沽、汉沽地区潜在淹没区的时空分布和面积。最后,提出了应对地面沉降的相关建议,以供政府控制地面沉降时参考。 相似文献
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A procedure is suggested of a more effective and faster computation of the impedance, the transfer function and amplitudes of the induced field in a spherically symmetric model of the electrical conductivity. The existing induction data have been supplemented by about 80 new values derived from the analysis of daily means. The fit of the existing 1-D models of the electrical conductivity of the mantle to the set of induction data is investigated. The characteristic equation for the free electromagnetic oscillations of a radially inhomogeneous Earth is derived and its possible importance in solving the inverse problem of electric conductivity is pointed out. 相似文献
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The rainfall‐runoff modelling of a river basin can be divided into two processes: the production function and the transfer function. The production function determines the proportion of gross rainfall actually involved in the runoff. The transfer function spreads the net rainfall over time and space in the river basin. Such a transfer function can be modelled using the approach of the geomorphological instantaneous unit hydrograph (GIUH). The effectiveness of geomorphological models is actually revealed in rainfall‐runoff modelling, where hydrologic data are desperately lacking, just as in ungauged basins. These models make it possible to forecast the hydrograph shape and runoff variation versus time at the basin outlet. This article is an introduction to a new GIUH model that proves to be simple and analytical. Its geomorphological parameters are easily available on a map or from a digital elevation model. This model is based on general hypotheses on symmetry that provide it with multiscale versatile characteristics. After having validated the model in river basins of very different nature and size, we present an application of this model for rainfall‐runoff modelling. Since parameters are determined relying on real geomorphological data, no calibration is necessary, and it is then possible to carry out rainfall‐runoff simulations in ungauged river basins. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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利用江苏重力测网2014—2017年重力场观测资料,采用绝对重力控制与相对重力联测相结合的平差方法,获取2016年射阳M_S 4.4地震前后重力场变化图。根据射阳M_S 4.4地震前后射阳地区各测线重力段差变化特点,绘制重力场等值线并进行对比分析,结合相关机理,探讨重力场变化与该地震的内在联系。同震观测数据显示:射阳M_S 4.4地震发生在重力异常值高梯度带附近,发震时震中地区位于NS挤压正异常、EW张拉负异常状态,震后区域重力梯度变化量开始减小,是一种典型的重力异常调整现象。 相似文献