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针对陆上三分量地震资料去噪处理中面临的面波噪声能量强、有效信号能量弱、转换波与面波主频叠置、非矢量保真处理等问题,本文基于多分量数据中有效信号与强面波噪声在极化属性、振幅能量、视速度三方面的特征差异,提出了一种时频域压制多分量数据强面波的去噪方法,并设计了相应的矢量滤波器。该方法利用小波变换将地震信号变换到时频域,并基于时频域瞬时极化率公式计算出各点极化率参数,然后根据面波视速度划分出有效信号区和面波噪声区,并据此对有效信号进行能量均值统计,最后联合极化率、能量、频率特征对噪声识别和分频、分区压制。理论模型和实际资料处理验证了本文方法的正确性和有效性,为解决低信噪比陆上多分量资料面波压制提供了又一种有效手段。 相似文献
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联合小波变换与偏振分析自动拾取微地震P波到时 总被引:1,自引:0,他引:1
对微地震P波到时的自动拾取是微地震信号分析和数据处理的主要目标之一。基于小波变换的多尺度分析思想,对微地震信号进行小波处理后的小波系数代替原始信号,应用包含在小波变换系数中的信号偏振信息,提出了联合小波变换与偏振分析自动拾取微地震信号P波到时的方法。通过对嘉阳煤矿监测的实际微地震数据进行小波变换,用多尺度小波分解的各个尺度单支重构信号构成协方差矩阵,求解不同尺度协方差矩阵的最大特征值和次大特征值求取P波到时定位函数,实现P波到时的自动拾取,取得了满意的结果. 相似文献
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面波压制是地震数据处理中的一个重要问题. 常规的处理方法虽然能在一定程度上压制面波,但是在处理过程中只是单一的利用面波的一种特性,例如频率域滤波中利用面波与有效信号频率之间的差别,因此难以有效地压制面波. 利用Ridgelet变换可将原始地震记录拓展到(a,τ,p)三维空间,从而可以同时利用地震记录的视速度、时间和尺度域特性差别,实现有效信号与面波的分离. 文中通过理论合成记录及实际地震记录的算例,证实了基于Ridgelet变换的面波压制方法是有效且可行的. 相似文献
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《地球物理学进展》2015,(6)
针对多分量地震数据具有信噪比低、波场比较复杂等特点,同时为了解决有效波和面波在低频带具有相关性且频带有重叠的部分.本文基于希尔伯特—黄变换(Hilbert—Huang transform,HHT)提出一种多分量地震数据去噪方法.HHT的核心部分是固有模态分解(Empirical mode composition method,EMD),它将地震信号自适应分解为各个尺度的固有模态函数(Intrinsic mode function,IMF);然后根据有效波和噪声分布在不同的分辨尺度范围内进行数据重构;对于一些尺度分布比较宽的,进行更加严格的EMD分解,以及通过瞬时参数阈值大小进行处理以达到更好的去噪效果.本文所做的工作主要针对多波资料中面波的处理,利用面波跟有效波的频率尺度和瞬时属性差异,从仿真数据、模型和实际地震数据进行面波的压制实验,取得了比较满意的压制效果,提高了地震资料的分辨率.也表明了该方法在多分量地震去噪处理中的可行性. 相似文献
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井间地震与常规地震相比具有较高的分辨率,同时波场也更加复杂.利用视速度特征的差异很容易地分离井间上下行波场,根据纵横波偏振特征的不同可将纵横波完全分离,但是针对井间地震侧面波的研究并不多.本文构建高速透镜体和断层模型进行波场数值模拟,通过对三维地震波场的传播特征进行分析可知,井间地震接收的波场既有岩性分界面的响应,还会有侧向地质不均匀体产生的干扰,严重影响成像的质量和精度.经偏振旋转后的T分量记录对物性横向变化较为敏感,综合分析X、Y、Z分量和T分量上不同连井剖面的波场传播特征,可对侧向传播的干扰波进行有效识别,利用线性Radon变换可以在一定程度上将侧面波进行压制,为后续井间地震资料处理提供高信噪比的数据.本文通过理论模型进行试算研究,验证了该方法的有效性,并对理论记录取得了较好的分离效果. 相似文献
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除介质各向异性之外,地球内部介质的横向非均匀性也是控制面波速度变化的重要因素.本文基于振型耦合和多重散射的地震波传播理论,数值模拟并分析了在具有均匀介质背景的三维异常体——上地幔横向非均匀介质中传播时,地震面波的振幅与偏振等动力学响应参数;其中分别模拟了不同周期入射、不同角度入射和不同尺度非均匀介质模型等多种情形下面波波场,并对横向非均匀性诱导的面波偏振异常进行了分析.结果表明,相对于长周期面波而言,短周期面波的振幅和偏振方向受横向非均匀性的影响更大,特别是偏振方向对地球结构的非均匀性更为敏感;切向分量存在横向非均性引起的Rayleigh与Love面波耦合现象;异常体边界处表现出强的面波波场响应. 相似文献
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The different characteristics of polarization of body and Rayleigh waves make it possible to separate these two types of waves
by their characteristics and suppress the latter. The moving time-window analysis often is used in polarization filtering
but it is difficult to determine a suitable time-window length, resulting in some problems, such as complex eigenvalues and
non-convergence. For overcoming these disadvantages, in this paper, we introduce the concept of complex-trace analysis and
conduct de-noise processing to suppress undesirable surface waves by instantaneous polarization analysis in the case of horizontal
and vertical component seismic recordings from the Hauinan coal mine. The performance of the method is illustrated by examples
with synthetic and field data and its effectiveness to remove surface waves from multi-component seismic data is demonstrated. 相似文献
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To improve the data quality of converted waves, and better identify and suppress the strong ground-roll interference in three-component (3C) seismic recordings on land, we present an adaptive polarization filtering method, which can effectively separate the groundroll interference by combining complex polarization and instantaneous polarization analysis. The ground roll noise is characterized by elliptical plane polarization, strong energy, low apparent velocity, and low frequency. After low-pass filtering of the 3C data input within a given time-window of the ground roll, the complex covariance matrix is decomposed using the sliding time window with overlapping data and length that depends on the dominant ground-roll frequency. The ground-roll model is established using the main eigenvectors, and the ground roll is detected and identified using the instantaneous polarization area attributes and average energy constraints of the ground-roll zone. Finally, the ground roll is subtracted. The threshold of the method is stable and easy to select, and offers good groundroll detection. The method is a robust polarization filtering method. Model calculations and actual data indicate that the method can effectively identify and attenuate ground roll while preserving the effective signals. 相似文献
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提出一种自适应协方差的时频域极化滤波方法。该方法在广义S变换时频方法的基础上,构造时频域自适应协方差矩阵,通过特征分析计算时频域瞬时极化参数,设计极化滤波器,实现多分量地震极化分析和滤波。其优势在于协方差矩阵的分析时窗的长度由多分量地震数据的瞬时频率确定,可以自适应于有效信号的周期,在每个时频点计算极化参数不需要进行插值处理;结合时间频率信息,解决在时间域或频率域波形或频率重叠的信号具有明显的直观性。模型数据及实际三分量台站地震数据处理结果表明,该极化滤波方法在台站地震资料分析和处理方面具有很好的直观性和较高的分辨率。 相似文献
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Mohsen Kazemnia Kakhki Webe J. Mansur Franciane C. Peters 《Geophysical Prospecting》2020,68(7):2104-2118
Obtaining geological information from seismic data motivates researchers to innovate and improve seismic wave processing tools. Polarization-based methods have received much attention regarding their ability to discriminate between different phases of the seismic wave based on polarity. Combining the intuitive definition of polarity in the frequency domain (monochromatic waves) with the non-stationary properties provided by time-domain methods, time-frequency approaches are attracting widespread interest because they localize the information extracted from the seismic waves in the joint time and frequency domains. Due to the lack of high-resolution time-frequency maps, the time-frequency polarization approach was not able to resolve specific temporal polarity changes in the seismic signal. The main objective of this study was to devise a robust time-frequency-based polarization filtering method using high-resolution polarization attributes obtained directly from the sparse time-frequency map without using Eigen analysis or analytic signals. The method proposed here utilizes a computationally effective sparsity-based adaptive S-transform to obtain a high-resolution polarization map of an inherently non-stationary seismogram for the entire frequency content of the signal at different times. The superiority of the proposed method over the S-transform method was verified using synthetic and real data sets to calculate the polarization attributes in the time-frequency domain and separate the Rayleigh waves from the seismogram. 相似文献
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One of the most important tasks in seismology and applied geophysics is the identification of the different kinds of waves that form a seismic record by means of polarization analysis. In particular, this involves the extraction of body waves (linear polarization) or surface waves (mostly elliptical polarization) from a set of seismic data and which forms a key point in several studies. 相似文献
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Field data from two-component in-seam seismic measurements are used to study roadway modes and their interaction with reflected seam waves. Using the multiple-filter technique to investigate the dispersion behaviour of the different waves, it can be shown that the roadway modes disperse very similarly to the related transmitted seam waves. However, because of the free surface of the coal face, the dispersion curves of the roadway modes show a velocity reduction and a slight shift to lower frequencies compared to those of the related transmitted seam waves. Polarization analysis using hodograms, rectilinearity and polarization angle confirms these results. The parameters found by polarization analysis can be used to design polarization filters which help to separate roadway modes and reflected events in the traveltime range of superposition in the presented field case. 相似文献
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In the paper, we propose a surface wave suppression method in time-frequency domain based on the wavelet transform, considering the characteristic difference of polarization attributes, amplitude energy and apparent velocity between the effective signals and strong surface waves. First, we use the proposed method to obtain time–frequency spectra of seismic signals by using the wavelet transform and calculate the instantaneous polarizability at each point based on instantaneous polarization analysis. Then, we separate the surface wave area from the signal area based on the surface-wave apparent velocity and the average energy of the signal. Finally, we combine the polarizability, energy, and frequency characteristic to identify and suppress the signal noise. Model and field data are used to test the proposed filtering method. 相似文献
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A new technique called the time-frequency polarization analysis was introduced in this paper. The technique combined the traditional
surface wave analysis techniques (moving window and multi-filter) with the singular value decomposition method to measure
the incidence azimuth of surface waves with different wavelengths. It was applied to study the progagation paths of surface
waves across the different blocks of Chinese continent and different zones of Qinghai-Xizang (Tibet) plateau. The results
show that the method can make full use of the differences in frequency compositions and arrival times of different surface
wave modes, and give better polarization analysis results. The analysis by actual data shows that the lateral heterogeneity
of the lithospheric structure influences the propagation paths of surface waves severely. Deviations of the paths across the
Qinghai-Xizang plateau from great circle paths are great. Deviations of the surface waves across the different zones in Qinghai-Xizang
plateau are different.
This project was sponsored by the Joint Earthquake Science Foundation. 相似文献
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IntroductionThe telluric field observation and study in ewthquake prediction are re-developed since lastdecade mainly due to following three reasons: @ Greek scientists claimed they have predictedvarious earthquakes with high successful rate by VAN approach in their ten years of observationsand researches, which has attracted attentions from various aspects in the world; @ The debate onVAN (Ruan, 1998; Uyeda, 1995) approach arid mechanism pllts forward many urgellt researchprojects which in… 相似文献