Combined traveltime and frequency-domain seismic waveform inversion: a case study on multi-offset ultrasonic data     

J.-X. Dessa  G. Pascal 《Geophysical Journal International》2003,154(1):117-133

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静效应校正的波数域滤波方法     

汤井田  何继善 《物探与化探》1993,17(3):209-216

探讨了在波数域作静效应校正的可能性,提出利用各频点互相关矩阵作为选择滤波截止波数的理论依据,并对三维数值模拟结果作了处理,表明在波数域消除静效应是可行的。最后,对云南某地的CSAMT数据作了试算,得出了较好的效果。  相似文献   

三维多尺度体曲率的算法及应用(英文)   总被引：2，自引：1，他引：1  

陈学华  杨威  贺振华  钟文丽  文晓涛 《应用地球物理》2012,9(1):65-72

为了充分提取与挖掘储层结构及构造信息在时间(深度)和空间上的多尺度特征,构造了一种新的三维多尺度体曲率分析方法,并给出了三维体曲率快速提取算法。与常规的体曲率方法相比,本文方法的改进主要体现在以下两个方面:①在体曲率分析中引入时频域分频展开和对应的空间波数域多尺度自适应微分算子,可同时在时间和空间上反映地震信息的多尺度特征;②将不同尺度的体曲率数据进行有机融合,充分利用了不同尺度曲率异常信息,同时突出有效异常,降低噪声影响,为体曲率属性解释奠定基础。利用该方法处理了陆上和海上三维地震资料,实现了对储层展布、断层及裂缝发育带的检测及多尺度特征的有效刻画。  相似文献   

基于波动方程的上下缆地震数据鬼波压制方法研究          下载免费PDF全文

管西竹  陈宝书  符力耘  陶杰  李列 《地球物理学报》2015,58(10):3746-3757

本文发展基于波动方程的上下缆鬼波压制方法,推导了上下缆地震波场频率波数域波动方程延拓合并公式.基于Fourier变换的波场解析延拓确保上下缆资料振幅相位的一致性,消除了长拖缆远偏移距信号的计算误差,同时具有较高的计算效率;上下缆地震波场的波动方程法合并有效解偶鬼波干涉,实现综合利用上下缆地震数据压制鬼波.理论模型数据和实际采集地震数据的测试表明了方法的有效性.  相似文献   

微动台阵法探测地下结构的实验研究     

魏运浩  李井冈  姚运生 《大地测量与地球动力学》2015,35(1):167-171

应用微动台阵法在江汉平原和长江大堤开展应用实验。结果表明,空间自相关法比频率-波数法结果更为稳定;通过变换台阵的尺寸可以探测浅至数米深至数百米的地下结构信息;利用台阵在空间上的平移观测可获取地下二维及三维的结构信息。  相似文献   

邢台地区长周期地震动特征初步分析     

贾晓辉  王晓山  付长华  刘爱文 《震灾防御技术》2019,14(1):87-96

沉积平原中存在地表低速沉积层是长周期地震动产生的关键因素,而长周期地震动会对长周期建筑物造成严重威胁和震害。本文基于邢台地震的历史地震震源模型和含地表沉积层的地壳速度模型,采用离散波数有限元法,对邢台地区进行了长周期地震动的计算分析。研究表明,邢台平原地区在大震中会产生长周期地震波,邢台地震中反应谱峰值区域位于宁晋南,与极震区基本重合。震中距小于55km区域内的周期1.5—4s的放大系数谱超过了抗震设计规范谱,反应谱放大系数值在周期2s附近达到峰值。因此,邢台地区因存在地表软弱沉积层,该区抗震设防可能对长周期地震动估计不足,建议应予以特别考虑。  相似文献   

PSV-wave propagation in a medium with local heterogeneities: a hybrid formulation and its application   总被引：1，自引：0，他引：1  

Helga Emmerich 《Geophysical Journal International》1992,109(1):54-64

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Two-dimensional elastic full waveform inversion using Born and Rytov formulations in the frequency domain   总被引：1，自引：0，他引：1  

C. Gélis  J. Virieux  G. Grandjean 《Geophysical Journal International》2007,168(2):605-633

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An Adaptive Wavenumber Sampling Strategy for 2.5D Seismic-Wave Modeling in the Frequency Domain     

Bing Zhou  Stewart Greenhalgh 《Pure and Applied Geophysics》2006,163(7):1399-1416

Simulation of seismic waves from a 3D point-source in a 2D medium may be performed in the frequency-wavenumber domain (called 2.5D modelling). It involves computing the Fourier-transformed Green's function for a number of frequency (ω) and strike direction wavenumber (k_y) values and doubly inverse transforming to convert to the traveltime and distance space. Such modeling produces a wavefield with 3D features but the computation becomes pseudo 2D (i.e., in the xz-plane) rather than 3D (in the xyz-frame). The common sampling strategy for the wavenumber is inefficient for 2.5D wave modeling because it employs a large number of wavenumbers (k_y). This leads to a high cost of computer time in the linear-equation-solving processing, which detracts from the advantages of 2.5D modeling. In this paper, we use two analytic frequency-wavenumber-domain solutions for seismic waves in a homogeneous medium and an inhomogeneous media (two semi-infinite media in contact) to investigate the properties of the solutions and an efficient sampling strategy for choosing the wavenumbers. We have carried out analytic and numerical experiments with these solutions, and present adaptive Gauss–Legendre abscissae for the wavenumber sampling in terms of a modeling situation. We show that the effective range and the number of sampling points of the wavenumber define the adaptive sampling strategy, and they can be estimated in terms of the wavelength and the maximum source-receiver offset. We apply this sampling strategy to the finite-element method and demonstrate that the range and number of sampling points may be adapted for obtaining significant computational efficiency and satisfactory accuracy for every frequency component. Such 2.5D wave modeling can be readily applied for frequency-domain full-waveform inversion for seismic surface measurements and crosshole seismic waveform tomography.  相似文献   

Inverting seismograms of weak events for empirical Green's tensor derivatives     

Vladimír Plicka  & Ji&#;í Zahradník 《Geophysical Journal International》1998,132(3):471-478

Given a station and a suite of clustered weak event records whose focal mechanisms are known, empirical Green's tensor spatial derivatives (EGTD) can be calculated, almost free of the source effects. The inversion method solves an overdetermined system of linear algebraic equations in the frequency domain, and a FFT provides the time histories. They represent a least-squares averaged representation of the path between the station and the entire focal zone, including multiple P and S phases, coda waves, etc. The method can be used for modelling earthquakes whose focal mechanisms are quite different from the weak events employed. This is proved here using both synthetic seismograms and earthquake swarm records with variable focal mechanisms. It is expected that the EGTD method can improve strong motion syntheses and source inversions.  相似文献