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一种地震子波提取的高阶累积量方法 总被引:2,自引:0,他引:2
提出1种在频率域实现地震子波提取的高阶累积量方法.其是先提取子波的相位谱再求解时间域的子波.理论上可适用于提取除零相位子波以外的任何形式的子波,但应用不同长度的时窗提取子波的效果会有很大的差别,实际应用时可利用时窗长度扫描的方法,以不同的子波相位谱对地震记录进行子波零相位化处理,最后根据最大方差模准则确定最佳子波.理论模型实验和实际资料处理实验均表明了该方法对最小相位及混合相位子波都有较好的处理效果. 相似文献
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本文综述时间延迟估计的基本原理和基本方法,包括相关法和广义相关法,双谱法和广义双谱法,相位谱法和广义相位谱法,自适应信号处理法等,并对各种估计方法的性能进行了分析比较。 相似文献
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实现地震道零相位化的子波相位谱消去法 总被引:2,自引:0,他引:2
子波相位谱消去法是通过话因式分解并以最大的方差模为准则求得子波相位港,然后将其从地震造的相位谱中消去。与常相住校正方法相比,该方法不要求于波各分频的初相位角为常数。模型实验表明,该方法具有良好的稳定性和对主频变化的适应性,首尾于波的主频相差30Hz时仍能得出很好的结果,这就使得我们对地震道可一次进行全道处理,而不必进行分段处理;对于最小相位地震道及接近最小相位的混合相位地震道,该方法具有较好的容噪能力。对于最大相位地震道及接近最大相让的混合相位地震道,当记录的信噪比较高时也有较好的效果。 相似文献
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南黄海以往一般采用单时窗合成地震记录,即对测井曲线求得反射系数与理论子波进行褶积,但由于地层浅部和深部的频率不同,导致合成地震记录和实际地震剖面吻合得不好.提出了对地震资料采用分时窗提取子波合成地震记录的方法,从井旁地震道提取地震子波进行频谱分析,地层浅部和深部地震子波的主频和波形不同,并考虑时延特性,采用分析结果的地... 相似文献
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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
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
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《中国海洋大学学报(自然科学版)》2016,(6)
单输入多输出系统提取地震子波的方法存在要求地震道之间的反射系数相同,子波多个且相异(即假设地震记录的差异全部由子波造成,与反射系数无关),以及对噪声敏感等缺陷。为了克服这种假设,本文利用地震数据的频率特征,运用二进正交小波变换Mallat算法的思想,讨论了两种构建伪单输入多输出系统的方法,推导了该系统下噪声子空间提取地震子波的算法,并进行了模型测试和实际资料验证工作。测试和验证结果显示该方法具有较强的抗噪能力。 相似文献
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由于地层吸收衰减等因素的影响,实际地震子波会随传播时间及空间发生变化,因此,若采用统一子波对非平稳地震记录进行反演将导致所求反射系数的不准确。本文利用改进广义S变换对地震资料进行时频分析,据此提取时变地震子波,重新构建时变子波褶积模型并求解相应的L1范数稀疏约束正则化问题,实现了基于改进广义S变换的时变反射系数反演,由此可获得与常规方法相比具有更高精度的反演结果。 相似文献
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在地壳中除一般的地震外 ,还可能发生其他不那么快速的地震过程。例如 ,在火山附近常记录到相当持续的振动 ,被称之为火山的抖动。2 0 0 0年日本开始起动由安置在全国各地、深度为 2 0 0~ 3 0 0m钻孔中的由 60 0台数字地震仪组成的“Hi 网络”。按仪器的灵敏度及其分布的密度 ,它超过了世界上所有其他类似的网络。“Hi 网络”记录到发生在南海俯冲区范围内地壳下层延续数分钟至数星期的振动。日本地震学家ObaraK成功地记录到离火山活动中心非常远的地壳振动。如果没有“Hi 网络”和在集中处理过程中所收集的资料 ,这些振动也许未被注意到… 相似文献
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The objective of this study is to determine numerical estimations of seismic amplifications of waves traveling from offshore to shore considering the effect of sea floor configurations. According to the Boundary Element Method, boundary elements were used to irradiate waves and density force can be determined for each element. From this hypothesis, Huygens’ Principle is implemented since diffracted waves are constructed at the boundary from which they are radiated and this is equivalent to Somigliana's theorem. Application of boundary conditions leads to determine a system of integral equations of Fredholm type of second kind, which is solved by the Gaussian method. Various numerical models were analyzed, a first one was used to validate the proposed formulation and some other models were used to show various ideal sea floor configurations to estimate seismic amplifications. Once the formulation was validated, basic slope configurations were studied for estimating spectra of seismic amplifications for various sea floor materials. In general terms, compressional waves (P-waves) can produce seismic amplifications of the incident wave in the order of 2–5. On the other hand, distortional waves (S-waves) can produce amplifications up to 5.5 times the incident wave. A relevant finding is that the highest seismic amplifications due to an offshore earthquake are always located near the shore-line and not offshore despite the seafloor configuration. 相似文献
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Seismic monitoring of western Pacific typhoons 总被引:2,自引:0,他引:2
Wu-Cheng Chi Wan-Jou Chen Ban-Yuan Kuo David Dolenc 《Marine Geophysical Researches》2010,31(4):239-251
Typhoons inflict large damage to societies, but are usually difficult to monitor in close proximity in real-time without expensive
instruments. Here we study the possibility of using seismic waveforms on the seafloor and on land to monitor the turning of
a far away or approaching typhoon. Up to 67% of the typhoons making landfall in Taiwan come from the eastern shore, so that
we deployed broadband ocean-bottom seismometers (OBSs) offshore eastern Taiwan in 2006 to study ground motion in close proximity
to a typhoon. Typhoons generate ocean waves, which generate pressure signals in the water column before being transmitted
to the seafloor as seismic waves and recorded by the OBSs. The ground motions on the seafloor correlate with locally increased
(ocean) wave heights and wave periods, suggesting that the ground motions are mostly induced by in situ or nearby pressure
fields, as shown by coherence function analyses. When a typhoon turns and changes wave-wave interaction near the source region,
a new set of en echelon patterns develops which can be observed by OBSs and land stations. Similar features occur when a typhoon crosses a landmass
and re-enters the ocean. The energy level ratio between the single-frequency and double-frequency microseisms also changes
abruptly when the typhoon turns. These features can potentially help near real-time early warning with little cost to complement
other conventional typhoon early warning methods. 相似文献
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