共查询到20条相似文献，搜索用时 15 毫秒
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K. N. D. Prasad N. Srinivas A. E. Meshram A. P. Singh V. M. Tiwari 《Journal of the Geological Society of India》2017,90(6):704-710
Koyna-Warna Region (KWR) is one of the known sites for reservoir triggered seismicity. The continued triggered seismicity over the five decades is restricted to a region of about 600–700 sq. km, which provides a unique opportunity to monitor geophysical anomalies likely to be associated with seismicity of the region. Present study confers temporal gravity changes recorded by gPhone and GRACE satellite and interprets observed changes in conjunction with seismological, geodetic (cGPS) observations and groundwater level measurements. GRACE data suggest that seasonal vertical deformation due to hydrological loading is ～ 2 cm, which corroborates with continuous GPS observations. Seasonal hydrological loading of the region, which is in a phase of reservoir loading, might be influencing the critically stressed KWR leading to the seasonal seismicity of the region. The gPhone gravity data distinctly show co-seismic gravity signals for eight earthquakes of Mw > 2 and gravity anomalies show positive correlation on a logarithmic scale with earthquake released energy. To investigate the cause of gravity changes, an estimate is made for 14th April 2012 earthquake for Mw 4.8 using fault dislocation model. The recorded gravity changes of 189 μGal by gPhone located at a distance of 28 km from the hypocentre is much more than the estimate of ～0.1 μGal calculated for Mw 4.8 Koyna earthquake. Therefore, it is inferred that co-seismic gravity signals for eight earthquakes are primarily caused due to redistribution of mass at shallow depth. 相似文献
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Modern geodetic techniques have developed rapidly in recent years, providing reliable observation data and new effective approaches, and greatly enhancing studies of the Tibetan geodynamics. For instance, the well-known GPS technique has been employed to measure seismic slips for many faults in the Tibetan Plateau. GPS data agree well with the hypothesis of a thickening crust and eastward mass flow. Moreover, absolute gravimetric data have been applied to interpret geophysical phenomena such as crust movement, co-seismic gravity change, GIA, and ground water change. The satellite gravity mission GRACE launched in 2002 provided global gravity models with unprecedentedly high precision and high spatial resolution. It has been used in implementing temporal gravity changes and improving our knowledge of the Earth’s interior, including lithosphere dynamics, mantle viscosity and rheology, plateau uplift, and subduction processing. It is noteworthy that gravity presents unique advantages for the study of Tibetan geodynamics because of its sensitivity to mass migration and dynamic redistribution. To date, great advances have been made in applying modern geodetic data in studying dynamic changes of Tibetan plateau. For instance, the horizontal displacement field from GPS data revealed dynamical characteristics of the present-day Tibetan plateau. The combination of gravity anomalies and topographic data describe the tectonic characteristics of Tibetan plateau. The combination of gravity data and GPS data show present properties of the Tibetan plateau such as crust thickening, Moho’s subsidence, and plateau uplift. GRACE data were used to estimate the distribution of ice/snow melting. 相似文献
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对近年升空的CHAMP和GRACE和将于2007年升空的GOCE卫星在测定地球重力场方面的技术特点和初步成果进行了回顾、比较和评估。并对它们今后在静态和动态的地球重力场构模方面可能的进展作一展望。现在只用一颗重力卫星的轨道摄动数据，就可以以前所未有的可靠性和精确性来求定地球重力场的长波和部分中波。如CHAMP重力卫星的33个月数据所求定的地球重力场模型,相对于曾利用多颗卫星资料所推算的GR1M5 S1重力场模型,在长波方面的精度和可靠性都有很大改善。而GRACE重力卫星的 110天数据所导出成果的空间分辨率，又优于CHAMP的33个月的数据成果。GRACE卫星还有一个重要任务，就是测定重力场非潮汐的短期性或准实时的变化。还介绍了新发表的一个联合地球重力场模型EIGEN CG03C, 360完全阶次，分辨率约30′。CG03C同CHAMP/GRACE以前的重力场模型比较，在400 km波长的精度方面改善了一个量级，大地水准面的精度改善了3 cm，重力异常的精度改善了0.4 mgal。 相似文献
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基于GRACE卫星测量得到的中国及其周边地区陆地水量变化 总被引：1，自引：0，他引：1
GRACE卫星成功开辟了空间大地测量对地观测的新途径。利用GRACE卫星得到的时变地球重力资料,分析估计了中国及其周边地区陆地水量的变化趋势,较为清晰地揭示了该地区季节性变化特征。进一步采用13点滑动平均的方法扣除了季节性变化,提取了4个特征区域(喜马拉雅南部,新疆与西藏及其周边的亚洲高山区域,中国华北、东北地区和中国南部地区)的陆地水量变化特征信息,这4个区域陆地水量的变化趋势分别为-12.7±0.7、-60.4±2.7、-12.5±0.5和6.6±0.9 km3/a。其中：喜马拉雅南部和亚洲高山区域陆地水量呈现明显的衰减趋势,与Matsuo和Heki模拟冰川质量损失源得到的结果较为一致;但近10年来亚洲高山区域西北部冰川加速融化趋势并不明显。中国华北、东北地区和南部地区水量变化比较复杂,具不稳定的变化趋势。 相似文献
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Holger Steffen Olga Gitlein Heiner Denker Jürgen Müller Ludger Timmen 《Tectonophysics》2009,474(1-2):69
Fennoscandia is a key region for studying effects of glacial isostatic adjustment. The associated mass variations can be detected by the Gravity Recovery and Climate Experiment (GRACE) satellite mission, which observes the Earth's gravity field since April 2002, as well as by absolute gravimetry field campaigns. Since 2003, annual absolute gravity (AG) measurements have been performed in Fennoscandia by the Institut für Erdmessung (IfE, Institute of Geodesy) of the Leibniz Universität Hannover, Germany, within a multi-national cooperation. This offers a unique opportunity for validation and evaluation of the GRACE results. In this preliminary study, the GRACE results are compared to secular gravity changes based on the surveys from 2004 to 2007 with the FG5-220 gravimeter of the IfE.The results from GRACE monthly solutions provided by different analysis centres show temporal gravity variations in Fennoscandia. The included secular variations are in good agreement with former studies. The uplift centre is located west of the Bothnian Bay, the whole uplift area comprises Northern Europe. Nevertheless, the differences between the GRACE solutions are larger than expected and the different centre-specific processing techniques have a very strong effect on possible interpretations of GRACE results. The comparison of GRACE to the AG measurements reveals that the determined trends fit well with results from GRACE at selected stations, especially for the solution provided by the GFZ. Variations of land hydrology clearly influence results from GRACE and the AG measurements. 相似文献
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M. A. Khan 《Natural Hazards》1992,5(2):125-132
The distinctive nature of the structure of the Earth's gravity field over high seismicity areas, as observed in some limited scale studies, indicates that it is possible to use these associative patterns to outline areas of high seismicity or high earthquake hazard potential from a knowledge of the finer structure of the Earth's gravity field. The global scale investigation of such relationships as a function of the geophysical characteristics of various tectonic provinces, and the parameterisation of such relationships by hypocentral depth and earthquake intensity/energy data, become even more attractive because of the availability of (1) satellite-determined gravity models which provide global information on the long wavelength components of the gravity field, (2) satellite altimetry data which provide oceanwide information on the detailed geoidal structure, (3) surface gravity data which provide information on the short wavelength components in the areas of surface gravity coverage, and (4) bathymetric and topographic data which, though still somewhat limited in spite of their recent extensions of coverage, are available in more and more areas and provide information on the tectonic and morphological environments of an area to enable its gravity data conversion to some standard environments for direct comparisons of underlying structures. Additionally, the rapidly mounting geological and geophysical evidence of considerable intraplate tectonic activity, not so fashionable until recently, makes the study of these correlative patterns even more attractive and productive from a scientific viewpoint. This paper presents the major elements of the theoretical formulation for conducting such investigations. 相似文献
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Recent decrease of water supply in central Asia and south Asia affects billions of people here. By filtering the errors at
higher frequency components and correcting for the contaminated components, we enhance the monthly GRACE gravity fields to
improve the determination of change in equivalent water height (EWH). The water storage changes from GRACE and the GLDAS hydrology
model all show decreasing trends in this region. At the annual and inter-annual time scales, significant correlations between
the variations in EWH and the variations in temperature, precipitation and snow equivalent height are found, especially at
high altitude stations, suggesting that climate change is the driving factor for the water depletion in central Asia and south
Asia. 相似文献
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龙门山及邻区断裂分布及地震前后断裂形态差异 总被引：1，自引：0，他引：1
利用欧拉方程(欧拉反褶积法)对龙门山地区重力数据进行反演,得到了地震前龙门山及邻区断裂的分布特征及参考深度。汶川地震波及范围广、破坏性大,地震前后发震断裂及周围断裂的形态必然会存在一定差异。笔者布设了一条实测重力剖面来对比地震前后断裂的形态。对比发现,地震后龙门山断裂带的逆冲趋势减弱,映秀—北川断裂与都江堰—江油断裂之间产生了多个破碎带。通过断裂形态的变化探究本次地震的成因,提出了应力面(第二地震面)和多震源的观点。 相似文献
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为了研究芦山地震的孕震过程和震源区的长期构造过程以及解释实测的震后形变和重力资料, 采用分层介质模型, 利用数值模拟的方法, 考虑区域流变系数, 计算了地震引起的地表同震、震后的形变和重力变化以及区域内部分GPS与重力连续观测台站的震后形变和重力变化的时间序列.结果表明: 芦山地震的地表同震形变显示出发震断层明显的逆冲特性; 粘弹性松弛效应引起的震后地表形变和重力变化比同震形变和重力变化的范围明显扩大, 但随着粘滞系数的增加, 变化量明显减小; 观测台站的震后变化时变曲线显示震后形变和重力变化在震后50 a间变化显著, 100 a后基本平缓, 趋于稳定; 模拟计算的GPS台站中除了MEIG台和MYAN台以外, 其余台站的震后观测必须考虑粘弹性松弛的影响. 相似文献
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为了研究大震(Ms≥7)和巨震(Ms≥8)与重力异常和活动断裂的关系.利用EIGEN-6C重力模型计算了相关地区的自由空气重力异常, 查阅了相关地区的布格重力异常和活动断裂构造.分析了重力异常突变带和活动断裂带与这些地震的空间分布.发现大震和巨震常在重力异常突变带和活动断裂带交汇处发生.结合前人对地球深部构造特征的研究, 提出了一种流变模型来解释大地震发生于重力异常突变带和活动断裂带交汇处的原因: 地壳深部流变层(体)流动受阻碍而引起重力异常和能量积累与释放. 相似文献
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The data acquired by Gravity Recovery and Climate Experiment (GRACE) satellite provides a new way for monitoring groundwater storage changes in China. It is vital to understand its applications in China. This paper systematically reviewed the research progress of groundwater storage monitoring in China based on GRACE data. First, we used the bibliometric analysis and quantitative analysis to clarify trends and characteristics of related studies. Then, we elaborated on the basic principles, methods and uncertainties of groundwater monitoring based on GRACE data. Furthermore, we reviewed the research progress from the aspects of spatial range, accuracies and findings. It was found that the groundwater storage monitoring in China based on GRACE data has gradually received more attention, and the numbers of relevant publications and total citations in both Chinese and English showed an increasing trend. The methods mainly include the principle of water balance and calibration of hydrological models using GRACE satellite data. Most of the relevant studies focused on the North China Plain. The monitoring results are in good agreement with the measured groundwater data, and their correlation coefficients are higher than 0.6. We suggested that the challenges such as low spatial resolution of GRACE data and the uncertainties in monitoring should be considered. In the future, global positioning system, interferometric synthetic aperture radar and groundwater level observation data can be integrated to improve the reliability of groundwater storage monitoring in China. 相似文献
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重力卫星五年运行对求定地球重力场模型的进展和展望 总被引：3，自引：0，他引：3
对近年升空的CHAMP和GRACE和将于2007年升空的GOCE卫星在测定地球重力场方面的技术特点和初步成果进行了回顾、比较和评估。并对它们今后在静态和动态的地球重力场构模方面可能的进展作一展望。现在只用一颗重力卫星的轨道摄动数据，就可以以前所未有的可靠性和精确性来求定地球重力场的长波和部分中波。如CHAMP重力卫星的33个月数据所求定的地球重力场模型，相对于曾利用多颗卫星资料所推算的GRlM5-S1重力场模型，在长波方面的精度和可靠性都有很大改善。而GRACE重力卫星的110天数据所导出成果的空间分辨率，又优于CHAMP的33个月的数据成果。GRACE卫星还有一个重要任务，就是测定重力场非潮汐的短期性或准实时的变化。还介绍了新发表的一个联合地球重力场模型EIGEN-CG03C，360完全阶次，分辨率约30′。CG03C同CHAMP／GRACE以前的重力场模型比较，在400km波长的精度方面改善了一个量级，大地水准面的精度改善了3cm，重力异常的精度改善了0．4mgal。 相似文献
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本文叙述了我国现行高程系统与ＧＰＳ高程系统垢区别,介绍了ＧＰＳ求解的大地高转换为正常高的几种方法,具体提出了１：２０万区域重力调查中用ＧＰＳ定位时所求测点高程应进行高程异常改正及高程异常对区域重力调查精度的影响。对区域重力调查及其它物化探测地工作有一这的指导意义。 相似文献
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In this study, regional evapotranspiration is estimated in a wide flatland area that includes Salado River Basin and four tributary basins by using gravity measurements of the space mission Gravity Recovery and Climate Experiment (GRACE). Monthly estimates of large-scale variations in the land-water storage are obtained from the satellite data. Evapotranspiration is computed with the water-balance equation using the GRACE land-water solutions, rainfall data from the Global Precipitation Climatology Center and runoff values obtained as 5% of the precipitation. GRACE-derived evapotranspiration values are consistent with the different climatic scenarios observed, and they satisfactorily agree with estimates provided by a global hydrological model. The overall results show that the method used is a valid tool for characterizing the evapotranspiration in the Argentine Pampas and that it can be used to detect and examine changes in the evapotranspiration pattern associated with the occurrence of extreme climatic events. This study illustrates the ability of GRACE to analyze and predict evapotranspiration and other processes on a regional scale in a flatland area. 相似文献
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Nowadays, Global Geopotential Models (GGMs) are used as a routine stage in the procedures to compute a gravimetric geoid.
The GGMs based geoidal height also can be used for GPS/levelling and navigation purposes in developing countries which do
not have accurate gravimetric geoid models. Also, the GGM based gravity anomaly including the digital elevation model can
be used in evaluation and outlier detections schemes of the ground gravity anomaly data. Further, the deflection of vertical
and gravity gradients components from the GGMs can be used for different geodetic and geophysical interpretation purposes.
However, still a complete and user-friendly software package is not available for universities and geosciences communities.
In this article, first we review the procedure for determination of the basic gravity field and gradient components from the
GGMs, then general MATLAB based software is presented and applied as a sample case study for determination of gravity components
based on the most recent EIGEN-GL04C GRACE model in Sweden.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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随着传感器技术的发展,重力场与重力张量场测量技术发展迅速,为实现地下密度分布精细反演提供了数据保障。正演是反演的基础,解决任意密度分布复杂地质体重力场与重力张量正演高效、高精度计算问题,是实现重力高效、精细反演、人机交互反演解释的关键。针对起伏地形和任意密度分布这种复杂条件下二维重力场及重力张量场高效高精度正演问题,这里提出了一种空间波数混合域正演算法,其关键环节包括:①结合新的矩形二度体组合模型波数域表达式和一维Gauss-FFT算法,提出了一种任意密度分布和起伏地形下重力场及重力张量高效、高精度正演算法;②采用新的二维正演算法,计算观测最高点和最低点之间多个不同高度水平网格重力场及重力张量,结合三次样条插值方法,实现了起伏地形上重力场及重力张量场高效、高精度正演。模型算例结果表明,新方法具有高效、高精度的显著特点。 相似文献