Inversion of sonic waveforms with unknown source and receiver functions     

L. Neil Frazer  Xinhua Sun  Roy H. Wilkens 《Geophysical Journal International》1997,129(3):579-586

A seismogram that is several times the length of the source-receiver wavelet is windowed into two parts—these may overlap—to obtain two seismograms with approximately the same source function but different Green's functions. A similarly windowed synthetic seismogram gives two corresponding synthetic seismograms. The spectral product of the window 1 data with the window 2 synthetic is equal to the spectral product of the window 1 synthetic with the window 2 data only if the correct earth model is used to compute the synthetic. This partition principle is applied to well-log sonic waveform data from Ocean Drilling Project hole 806B, a slow formation, and used there to estimate Poisson's ratio from a single seismogram whose transmitter and receiver functions are unknown. A multichannel extension of the algorithm gives even better results. The effective borehole radius R _b, was included in the inversion procedure, because of waveform sensitivity to R _b. Inversion results for R _b agreed with the sonic caliper, but not the mechanical caliper; thus if R _b is not included in the inversion its value should be taken from the sonic caliper.  相似文献   

伽玛测井多点式反褶积法及其负值含量问题的讨论     

汤彬  陆玲 《铀矿地质》1991,7(2):99-107

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海上地震虚反射相位剔除法反褶积   总被引：4，自引：0，他引：4  

刘建磊  王修田 《海洋地质与第四纪地质》2002,22(4):117-121

在分析了虚反射的形成机制及其滤波器频谱特性的基础上，提出了一种在频率域剔除地震鬼波的新方法，该方法直接剔除的是虚反射滤波器相位谱的影响，而对于振幅谱，则是通过同时消除虚反射与地震子波两者共同的影响来拓宽地震记录的有效频谱，处理过程自动避免了鬼波滤波器的“零值点”问题，其最终结果是以获取反射生活费数为期望输出，因此，该方法在消除鬼波的同时可进一步提高地震剖而后 分辨率。实验表明，本文所提出的反褶积方法具有较好的容噪能力。且在鬼波延迟时以及虚反射界面反射系数存在一定误差的情况下仍能获得令人满意的处理结果。  相似文献   

带乘性噪声系统在加性噪声相关时的最优固定域平滑及反褶积算法     

刘滨  褚东升  王远  梁猛 《中国海洋大学学报(自然科学版)》2002,32(4):645-649

最优平滑及最优反褶积在石油地震勘探、通讯工程、语音处理等应用领域都具有十分重要的意义。以往的带乘性噪声系统的平滑及反褶积大都对系统模型的噪声特性有着较强的限制条件 ,要求动态噪声及观测噪声互相独立或只能在同时刻相关。该文给出了一种在动态噪声为有色噪声及动态噪声和量测噪声在有限时间段上相关的情形下带乘性噪声系统的固定域平滑及反褶积算法 ,该算法在线性最小方差意义下是最优的。通过仿真计算 ,说明了该算法的有效性。  相似文献   

Deconvolution of squared velocity waveform as applied to the study of a noncoherent short-period radiator in the earthquake source     

A. A. Gusev  V. M. Pavlov 《Pure and Applied Geophysics》1991,136(2-3):235-244

We consider an inverse problem of determination of short-period (high-frequency) radiator in an extended earthquake source. This radiator is assumed to be noncoherent (i.e., random), it can be described by its power flux or brightness (which depends on time and location over the extended source). To decide about this radiator we try to use temporal intensity function (TIF) of a seismic waveform at a given receiver point. It is defined as (time-varying) mean elastic wave energy flux through unit area. We suggest estimating it empirically from the velocity seismogram by its squaring and smoothing. We refer to this function as observed TIF. We believe that one can represent TIF produced by an extended radiator and recorded at some receiver point in the earth as convolution of the two components: (1) ideal intensity function (ITIF) which would be recorded in the ideal nonscattering earth from the same radiator; and (2) intensity function which would be recorded in the real earth from unit point instant radiator (intensity Green's function, IGF). This representation enables us to attempt to estimate an ITIF of a large earthquake by inverse filtering or deconvolution of the observed TIF of this event, using the observed TIF of a small event (actually, fore-or aftershock) as the empirical IGF. Therefore, the effect of scattering is stripped off. Examples of the application of this procedure to real data are given. We also show that if one can determine far-field ITIF for enough rays, one can extract from them the information on space-time structure of the radiator (that is, of brightness function). We apply this theoretical approach to short-periodP-wave records of the 1978 Miyagi-oki earthquake (M=7.6). Spatial and temporal centroids of a short-period radiator are estimated.  相似文献   

Surface-Related Multiple Elimination on High-Resolution Geopulse Profile     

崔树果  刘怀山  贺懿  吴金龙 《中国海洋工程》2008,22(2):331-339

A geopulse seismic system was implemented to obtain new information on underlying strata beneath the Yellow River Delta. However, owing to the shpping of sea floor and shallow water （ 〈 25 m）, free surface-related multiples are conflicted with the flat primaries, which may instruct the interpreters in a wrong way and make wrong conclusions. Owing to the variation of multiple periods, standard anti-multiple techniques may lose their power, such as predictive deconvolution. Surface-related multiple elimination methods are introduced to attenuate the multiples based on the underlying waveequation principles. The results justified the method on the single-channel geopulse profile, revealing the real nature of the subsurface.  相似文献   

A blind deconvolution method for ground based telescopes and Fizeau interferometers     

《New Astronomy》2015

In the case of ground-based telescopes equipped with adaptive optics systems, the point spread function (PSF) is only poorly known or completely unknown. Moreover, an accurate modeling of the PSF is in general not available. Therefore in several imaging situations the so-called blind deconvolution methods, aiming at estimating both the scientific target and the PSF from the detected image, can be useful. A blind deconvolution problem is severely ill-posed and, in order to reduce the extremely large number of possible solutions, it is necessary to introduce sensible constraints on both the scientific target and the PSF.In a previous paper we proposed a sound mathematical approach based on a suitable inexact alternating minimization strategy for minimizing the generalized Kullback–Leibler divergence, assuring global convergence. In the framework of this method we showed that an important constraint on the PSF is the upper bound which can be derived from the knowledge of its Strehl ratio. The efficacy of the approach was demonstrated by means of numerical simulations.In this paper, besides improving the previous approach by the use of a further constraint on the unknown scientific target, we extend it to the case of multiple images of the same target obtained with different PSFs. The main application we have in mind is to Fizeau interferometry. As it is known this is a special feature of the Large Binocular Telescope (LBT). Of the two expected interferometers for LBT, one, LINC-NIRVANA, is forthcoming while the other, LBTI, is already operating and has provided the first Fizeau images, demonstrating the possibility of reaching the resolution of a 22.8 m telescope. Therefore the extension of our blind method to this imaging modality seems to be timely.The method is applied to realistic simulations of imaging both by single mirrors and Fizeau interferometers. Successes and failures of the method in the imaging of stellar fields are demonstrated in simple cases. These preliminary results look promising at least in specific situations. The IDL code of the proposed method is available on request and will be included in the forthcoming version of the Software Package AIRY (v.6.1).  相似文献   

基于多手段异常结果的地震综合概率预测     

窦喜英  王恩利  张丽琼  李敏娟  马海萍 《地震地磁观测与研究》2021,42(2):141-142

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鄂尔多斯南缘地区重力变化场源特征     

张永奇  韩美涛  郑增记  曹建平 《地震地磁观测与研究》2021,42(3):84-96

以鄂尔多斯南缘地区布格重力异常数据及2014—2017年相对重力观测数据为基础,采用欧拉反褶积方法,对引起重力变化的场源深度进行反演,并对空间分布规律予以解释。通过构建理论模型,反演得到最优模型参数,并对实际数据进行计算和分析。为了减弱和消除欧拉解的发散性,利用水平梯度滤波法优化反演结果。结果表明:①构造指数为1时,适合对相对重力数据进行反演,当滑动窗口选择4—8倍测点间距时,可以获得较为可靠的场源参数;②在主要断裂附近,不同时间尺度的场源呈较好的一致性特征;③引起重力变化的场源深度集中在10—30 km,与鄂尔多斯南缘地区的震源深度基本一致;④不同时间尺度的场源位置相对分散,表明引起重力变化的物质流动具有随机性和波动性。  相似文献   

基于透岩浆流体成矿理论的GIS矿产预测研究     

赵增玉  潘懋  潘赟  张志虎 《地质论评》2010,56(2):299-304

本文以内生金属矿床透岩浆流体成矿理论为基础,以分级预测体制的思想为指导,认为在成矿理论指导下提出的各级预测体制对应的宏观地质标志是连接透岩浆流体成矿理论与GIS成矿信息的纽带,并从成矿地质背景、成矿作用触发机制和金属大规模堆积三方面,分别说明了各级预测体制及可能利用的宏观地质标志,最后通过研究目前广泛使用的GIS评价方法,初步建立起透岩浆流体成矿理论应用于宏观地质标志矿产预测的GIS预测系统框架。  相似文献