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纵、横波的分离是多波多分量地震资料处理中很重要的一步,其分离结果直接影响到后续数据处理的质量.各向同性介质中纵波为无旋场,横波为无散场,因此可以在频率-波数域利用散度和旋度算子对地震记录进行纵、横波分离,但是此处理过程必须知道地表处的纵、横波速度.本文给出了一种估算地表纵、横波速度的方法,可以在纵、横波速度值未知的情况下,将其估算出来.针对弹性波场进行散度和旋度运算时,纵、横波的相位和振幅比发生改变的问题,本文给出了相位和纵、横波振幅比的校正方法. 相似文献
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利用成都区域数字化地震台网记录的雅江地震序列的波形资料,使用波谱分析方法,通过纵、横波的零频谱值的比值得到了雅江地震序列前及余震的纵、横波速比。结果表明,雅江地震序列纵、横波速比在主震前后存在不同变化,不同台站求得的波速比变化过程也存在明显差异。 相似文献
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巷道前方煤体波速与瓦斯参数相关分析研究 总被引：1，自引：0，他引：1
为了获取掘进巷道前方煤体地震波速度和瓦斯参数间的对应关系,以阳泉五矿为实施矿井.采用矿井地震波速度超前探测方法对掘进煤巷进行探测,通过初至波拾取获得地震波原始记录中纵、横波速,并与巷道前方30m范围内平均瓦斯参数作相关分析.分析结果表明:一定条件下,煤体瓦斯含量越高,其地震波纵、横波速度越低.运用曲线拟合对纵、横波视速度与瓦斯绝对涌出量和瓦斯浓度进行拟合发现:纵、横波视速度与瓦斯绝对涌出量间存在ΔP=-4.6415Vp-2.7048Vs+16.1353的负线性关系;纵、横波视速度与瓦斯浓度间存在η=-0.9302Vp-0.5704Vs+3.3132的负线性关系,并对线性拟合结果进行验证表明:在误差允许范围内,计算值与实测值基本吻合.最后计算得到适用于太原组15#煤层及变质程度更高煤层的视速度瓦斯预警指标:Vp=2.00m/ms和Vs=0.73m/ms. 相似文献
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以三维高分辨地震与海底高频地震仪（OBS）联合勘探数据为基础,获得海底之下沉积层的地震反射成像剖面及多波信息,并以此确定研究区含天然气水合物沉积层的纵、横波速度的变化特征.根据走时反演获得的横波速度与纵波速度对比分析发现,研究区海底之下500 m深度范围内的某些沉积层具有较高的纵横波速度,这一纵波速度升高区域与水合物稳定带对应,而纵波速度下降并且横波速度变化较小的区域,可能与游离气的存在相关.游离气的可能存在与基于这一区域2007年钻探测井结果的普遍认识不完全相符. 相似文献
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本文提出了一种新的反演方法:通过采用纵、横波走时数据对(从相同的震源产生的P和S波被同一台站记录)来联合反演纵波速度(Vp)和纵、横波速度比(Vp/Vs),然后单独反演横波速度Vs,在反演过程中同时对地震参数进行定位。该方法不需要假设P和S波的射线路径一致,它是沿着P和S波射线路径计算相对慢度扰动值。该方法直接把Vp/Vs作为一个模型参数,由此能获得比采用从独立反演获得的Vp和Vs计算出Vp/Vs的方法更精确的速度比值。该新方法被应用到反演日本东北地区的壳幔速度及波速比结构的研究中,获得了较好的效果。反演结果表明,在日本东北地区,太平洋俯冲板块为一高Vp,高Vs和低Vp/Vs异常区,而在活火山下方的浅部地幔楔以及背弧深部地区为低Vp,低VS和高Vp/VS异常。虽然这些特征在前人的研究中已经报道过,但与前人的研究结果相比,本次研究所获得的Vp/Vs的空间分布具有较小的分散性,同时,它的分布特征能较好的与地震波速度结构相吻合。 相似文献
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《应用地球物理》2015,(1)
本文是三分量地震在陆相薄互层地震勘探中应用成功的首例。大庆长垣喇嘛甸油田处于高含水开发后期,储层预测的主要难题是密井网条件下厚度2m以上砂体的边界识别问题,常规单一纵波地震解释存在多解性,引入横波信息可增加地震解释的可靠性。本文根据纵、横波对气藏的响应特征,利用纵、横波联合振幅属性、分频属性对气藏进行了分析,能够很好地反应气藏的边界,体现了横波受流体影响较小的优势。通过测井曲线岩石物理定量的分析了该地区主要是密度、λρ和μρ三种物性参数能够很好地反映储层岩性变化。在以地震数据分频为核心的高精度地震参考标准层解释基础上利用纵、横波联合反演得出的纵、横波速度比、λρ、μρ等属性与测井解释的储层具有很好的一致性,多波属性λρ沿层切片描述了开发小层的砂体平面展布,与井砂岩图具有较高的一致性,刻画了井间砂体边界变化的细节,并指示了剩余油挖潜的有利区域。 相似文献
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天然气水合物饱和度是评估天然气水合物资源量的重要参数,而用来估算饱和度的速度模型则是有限的几个,它们有的为经验公式,有的是以实验数据或野外资料为基础建立起来的,需要进行实验验证和参数分析以确定其使用的适用性.本文首次利用超声和时域反射联合探测技术,研究了沉积物中水合物饱和度与声学特性的关系,并对时间平均方程、伍德及其修正方程、李权重方程和BGTL（Biot-Gassmann Theory by Lee）理论等常用的水合物饱和度估算模型进行了验证.实验结果表明,超声和时域反射联合探测技术能有效地实时获得水合物饱和度和纵、横波速的实验数据,李权重方程和BGTL理论的速度预测值与实验值比较吻合,有广泛的适用性. 相似文献
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The wave field patterns of the propagation of longitudinal and transverse elastic waves in grain-oriented rocks 总被引：1，自引：0，他引：1
A. N. Nikitin T. I. Ivankina V. K. Ignatovich 《Izvestiya Physics of the Solid Earth》2009,45(5):424-436
In the work under consideration, on the basis of data analysis on the velocities of quasi-longitudinal Vp and quasi-transverse Vs waves—measured for rock samples at high pressures and temperatures, and analogous velocities, calculated on the basis of the grain orientation distribution function, reconstructed from the neutron-diffraction textural experiment—the indicative inconsistencies between the experimental and model characteristics were inferred. The theoretical analysis of the wave field patterns of the propagation of longitudinal and transverse elastic waves in the anisotropic media is carried out. It is established that, in the general case, in the anisotropic inhomogeneous media the velocities of Vp and Vs propagation, measured experimentally and obtained from the modeling, cannot coincide due to the existence of the physical coupling between the vibrations of two types: transverse and longitudinal vibrations. 相似文献
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Alemayehu Lakew Jemberie 《Pure and Applied Geophysics》2008,165(9-10):1835-1860
Strong and weak motion data from the Mississippi Embayment Seismic Excitation Experiment (ESEE) were analyzed for signatures of nonlinear site responses. This experiment was performed jointly by the University of Memphis and U. S. Geological Survey in October 2002, by detonating two explosions of 2500 and 5000 lbs. Intrinsic and scattering Q estimates (QI and QS) from the coda of the strong motion data were found to be very low compared to previously determined Q values of P- and Rayleigh waves of weak motion data from the same explosions. The QI estimates from P-wave late coda of the strong motion data are less by more than 100 at 3 Hz and by more than 200 at 10 Hz, compared to the P-wave Q values determined from the weak motion data by Langston et al (2005). Also, QI determined from the late coda of strong motion Rayleigh-wave data is less by more than 200 at 0.5 Hz and by more than 50 at 3.0 Hz, compared to Q values determined from Rayleigh-wave weak motion data. A resonance peak spectral amplitude of the early part of a strong motion seismogram is shifted to lower frequencies compared to that from a later part of the same seismogram. Spectral amplitude ratios between transverse and vertical components of the strong motion data are degraded between frequencies 2 and 10 Hz for P waves, and less than 4 Hz for Rayleigh waves compared to the weak motion transverse to vertical spectral ratio. All these are signatures of nonlinear site responses during strong ground motion. This study proves the non-transportability of weak motion attenuation results to estimate ground motion from a future large earthquake that may take place in areas like the New Madrid Seismic zone. 相似文献
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本文用单台多重滤波方法测定了经过青藏高原地区瑞利波群速度频散曲线。所得基阶瑞利波的观测周期为5.0-56.0秒,速度标准偏差为0.08-0.15公里/秒,一阶瑞利波的观测周期范围为10-16秒,速度标准偏差为0.05-0.13公里/秒。利用广义线性反演方法对频散曲线进行反演,可得出一个由五层构成的地震横波速度地壳模型。在27-40公里之间存在低速层,其横波速度为3.29公里/秒,比上一层低0.21公里/秒。 相似文献
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Dynamical properties of an anchorage of South Bisan-seto Suspension Bridge are determined by means of in situ measurement of the ambient vibrations. This anchorage, being located in the sea, is tall and slender; its natural frequencies are expected to be low. On the other hand, the elasticity of the ground estimated from the conventional geological data is highly dispersed. It even suggests the possibility of resonance between the towers and this anchorage. It is therefore necessary to know its natural frequencies precisely. Seismic motions and microtremors are acquired and used properly. The observation is repeated every year during the period of construction of the anchorage so that its inertial properties change significantly. First modes of the longitudinal and the transversal vibrations of the anchorage are identified and their frequencies determined. The elasticity modulus estimated from these natural frequencies is about five times as large as that of the geological survey while it is consistent with that obtained from the velocity of the elastic waves of the ground. 相似文献
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Tapendra Nath Maulik 《Pure and Applied Geophysics》1964,58(1):49-62
Summary It has been found that when seismic energy propagates along the surface of the homogeneous crust beside usual Rayleigh waves, it produces certain instability in layers through which it propagates. In the light of this instability, a type of motion corresponding to longitudinal wave will be prominent in horizontal component compared to the vertical component; while transverse wave will be prominent in the vertical component but weak in the horizontal component, a contradiction with the existing knowledge. This has been identified withP
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phase. On taking the medium of propagation as slightly heterogeneous which allows existence of low velocity layer, a few larger number of such instabilities have been found. Velocity equation for Rayleigh waves for such media reveals existence of different velocities corresponding to vertical and horizontal components. Table for these velocities has been furnished. 相似文献
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Markus Båth 《Pure and Applied Geophysics》1966,65(1):5-11
Summary The vertical velocity variations of longitudinal and transverse waves in the earth's interior in the depth range of 413 to 2800 km are put into mathematical form. Expressions of the velocities in terms of power functions of the radius are found to conform closely to the given velocities, as well as to be very simple in applications. Examples of the use of such formulas are given, including calculations of travel times and of radial velocity gradients. 相似文献
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F. F. Gorbatsevich V. R. Vetrin O. M. Trishina M. V. Kovalevsky 《Izvestiya Physics of the Solid Earth》2014,50(4):514-527
Based on the experimental and calculated data, the model of depth variations in density, as well as the velocities of longitudinal (P) and transverse (S) waves, within the upper, middle, and lower crusts of the Kola-Norwegian block down to a depth of about 40 km is suggested. The variations in density and the velocities of the P- and S-waves are primarily caused by the changes in the mineral composition of the rocks. The relative reduction in the velocities of the P- and S-waves under the action of the increasing pressure and temperature in the depth interval from 5 to 37 km is estimated at ～2%. 相似文献
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在对声波测井进行概括分析的基础上,发现了两个新的共振模式,它们正好是不衰减的首波和次首波。导出了它们的分立频谱,给出了波速和波幅的简单公式。 相似文献
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The effect of seawater on vertical ground motions is studied via a theoretical method and then actual offshore ground motion records are analyzed using a statistical method. A theoretical analysis of the effect of seawater on incident plane P and SV waves at ocean bottom indicate that on one hand, the affected frequency range of vertical ground motions is prominent due to P wave resonance in the water layer if the impedance ratio between the seawater and the underlying medium is large, but it is greatly suppressed if the impedance ratio is small; on the other hand, for the ocean bottom interface model selected herein, vertical ground motions consisting of mostly P waves are more easily affected by seawater than those dominated by SV waves. The statistical analysis of engineering parameters of offshore ground motion records indicate that:(1) Under the infl uence of softer surface soil at the seafl oor, both horizontal and vertical spectral accelerations of offshore motions are exaggerated at long period components, which leads to the peak spectral values moving to a longer period.(2) The spectral ratios(V/H) of offshore ground motions are much smaller than onshore ground motions near the P wave resonant frequencies in the water layer; and as the period becomes larger, the effect of seawater becomes smaller, which leads to a similar V/H at intermediate periods(near 2 s). These results are consistent with the conclusions of Boore and Smith(1999), but the V/H of offshore motion may be smaller than the onshore ground motions at longer periods(more than 5 s). 相似文献
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High-frequency surface-wave analysis methods have been effectively and widely used to determine near-surface shear (S) wave velocity. To image the dispersion energy and identify different dispersive modes of surface waves accurately is one of key steps of using surface-wave methods. We analyzed the dispersion energy characteristics of Rayleigh and Love waves in near-surface layered models based on numerical simulations. It has been found that if there is a low-velocity layer (LVL) in the half-space, the dispersion energy of Rayleigh or Love waves is discontinuous and ‘‘jumping’’ appears from the fundamental mode to higher modes on dispersive images. We introduce the guided waves generated in an LVL (LVL-guided waves, a trapped wave mode) to clarify the complexity of the dispersion energy. We confirm the LVL-guided waves by analyzing the snapshots of SH and P–SV wavefield and comparing the dispersive energy with theoretical values of phase velocities. Results demonstrate that LVL-guided waves possess energy on dispersive images, which can interfere with the normal dispersion energy of Rayleigh or Love waves. Each mode of LVL-guided waves having lack of energy at the free surface in some high frequency range causes the discontinuity of dispersive energy on dispersive images, which is because shorter wavelengths (generally with lower phase velocities and higher frequencies) of LVL-guided waves cannot penetrate to the free surface. If the S wave velocity of the LVL is higher than that of the surface layer, the energy of LVL-guided waves only contaminates higher mode energy of surface waves and there is no interlacement with the fundamental mode of surface waves, while if the S wave velocity of the LVL is lower than that of the surface layer, the energy of LVL-guided waves may interlace with the fundamental mode of surface waves. Both of the interlacements with the fundamental mode or higher mode energy may cause misidentification for the dispersion curves of surface waves. 相似文献