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小波多尺度分解特征分析 被引量:12
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作者 刘少明 申重阳 +1 位作者 孙少安 陈步云 《大地测量与地球动力学》 CSCD 2004年第2期34-41,共8页
介绍了小波多尺度分析的数学原理 ,以三峡 13期流动重力资料为例进行了小波分解。讨论了网格距对三峡流动重力资料分解结果的影响 ,提出了一种计算平均点距的方法 ;讨论了小波阶数与重力变化波长的关系 ,根据网格距及小波理论计算了各... 介绍了小波多尺度分析的数学原理 ,以三峡 13期流动重力资料为例进行了小波分解。讨论了网格距对三峡流动重力资料分解结果的影响 ,提出了一种计算平均点距的方法 ;讨论了小波阶数与重力变化波长的关系 ,根据网格距及小波理论计算了各阶小波及逼近对应的波长范围。讨论了重力变化区移动与数据延拓、网格加密、网形完整性以及小波计算起始点之间的关系。结果表明 ,如重力网形不完整 ,分解结果中重力变化区随小波阶增加的移动没有规律 ,如果网形完整 ,分解结果普遍存在随小波阶增加而有规律移动的负重力变化区。 展开更多
关键词 小波多尺度分解 长江三峡 流动重力 重力变化区
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Estimating Field Source Parameters of Gravity Change in North China Based on the Euler Deconvolution Method
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作者 Liu Fang Zhu Yiqing Zhao Yunfeng 《Earthquake Research in China》 CSCD 2017年第2期247-256,共10页
Based on the absolute and relative gravity observations in North China from 2009 to 2014,spatial dynamic variations of the regional gravity field are obtained. We employed the Euler deconvolution method and the theore... Based on the absolute and relative gravity observations in North China from 2009 to 2014,spatial dynamic variations of the regional gravity field are obtained. We employed the Euler deconvolution method and the theoretical model to get the best estimates of parameters. Gravity field change caused by the depth and distribution in North China is calculated by back analysis. The results show the structural index that equals 1 is suitable for inversion of the gravity variation data. The inversion results indicate that the depths of anomaly field sources are spread over the Hetao fault. The research method of this paper can be used in the quantitative study on the field source and may shed new light on the interpretations of gravity change, and also provide quantitative basis for earthquake prediction index criterions based on the gravity change. 展开更多
关键词 Euler deconvolution Potential field inversion Gravity change Structural index North China
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Discrete Wavelet Multi-scale Decomposition of the Temporal Gravity Variations in North China
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作者 Liu Fang Zhu Yiqing Chen Shi 《Earthquake Research in China》 2014年第3期360-369,共10页
On the basis of the absolute and relative gravity observations in North China,spatial dynamic variation of regional gravity fields is obtained. A multi-scale decomposition technique is used to separate anomalies at di... On the basis of the absolute and relative gravity observations in North China,spatial dynamic variation of regional gravity fields is obtained. A multi-scale decomposition technique is used to separate anomalies at different depths,and give some explanation to gravity variation at different time space scales. Gravity variation trends in North China are improved. Based on this result and the analysis of wavelet power spectrum,the images of the depth of wavelet approximation and detail are obtained. The results obtained are of scientific significance for the deep understanding of potential seismic risk in North China from gravity variations in different time space scales. 展开更多
关键词 Wavelet decomposition MULTI-SCALE Gravity variation field POWERSPECTRUM North China
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Effects of Gaussian filter in processing GRACE data: Gravity rate of change at Lhasa,southern Tibet 被引量:5
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作者 SUN WenKe HASEGAWA Takashi +3 位作者 ZHANG XinLin FUKUDA Yoichi SHUM C. K. WANG Lei 《Science China Earth Sciences》 SCIE EI CAS 2011年第9期1378-1385,共8页
In this paper, the spatial gravity distribution over Tibetan Plateau and the gravity rate of change at Lhasa for different Gaussian filter radii are computed using GRACE data. Results show that the estimate of the gra... In this paper, the spatial gravity distribution over Tibetan Plateau and the gravity rate of change at Lhasa for different Gaussian filter radii are computed using GRACE data. Results show that the estimate of the gravity rate of change is spatialradius-dependent of the Ganssian filter. The GRACE-estimated gravity rate of change agrees well with the surface measured one. In other words, the GRACE-estimated gravity rate of change has a limited value as that obtained by surface measurement when the spatial filter radius reaches zero. Then numerical simulations are made for different spatial radii of the Gaussian filter to investigate its behaviors when applied to surface signals. Results show that the estimate of a physical signal is filter-radius dependent. If the computing area is equal to or less than the mass area, especially for a uniformly distributed mass, the estimate gives an almost correct result, no matter what filter radius is used. The estimate has large error because of the signal leakage caused by harmonic truncation if the computing area is much bigger than the mass distribution (or inverse for a small mass anomaly). If a mass anomaly is too small, it is difficult to recover it from space observation unless the filter radius is extremely small. If the computing point (or area) is outside the mass distribution, the estimated result is almost zero, particularly for small filter radii. These properties of the Gaussian filter are helpful in applying GRACE data in different geophysical problems with different spatial position and geometrical size. We further discuss physical sources causing the scalar gravity change at Lhasa. Discussions indicate that the gravity rate of change at Lhasa is not caused by the present-day ice melting (PDIM) (or Little Ice Age, LIA) effect because no ice melting occurs in Lhasa city and nearby. The gravity rate of change is attributable mainly to tectonic deformation associated with the Indian Plate collision. Simultaneous surface displacement, surface denudation, and GIA effects are not negligible. 展开更多
关键词 gravity change GRACE Gaussian filter Tibetan Plateau LHASA
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