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1.
Preliminaryresultof3DgravitationalforwardcalculationstudyinBohaiSeaGUANGXIALIU1)(刘光夏)WENJUNZHAO2)(赵文俊)WENJUREN1)(任文菊)XIU...  相似文献   

2.
CrustaldeformationofseismogenicfaultanditssuroundingareaaftertheTangshanearthquakeJUEMINXIE(谢觉民)RUOBAIWANG(王若柏)WANGJUBO(...  相似文献   

3.
Effectsofmagnitudeaccuracyandcomplete┐nesdataonseismichazardparametersHUI-CHENGSHAO(邵辉成),JIA-SHUXIE(谢家树),PINGWANG(王平)andYA-X...  相似文献   

4.
A new method for dynamic inversion of anisotropic equations   总被引:1,自引:0,他引:1  
AnewmethodfordynamicinversionofanisotropicequationsDING-HUIYANG1)(杨顶辉)JI-WENTENG2)(滕吉文)ZHONG-JIEZHANG2)(张中杰)1)DepartmentofGe...  相似文献   

5.
Inversion of Q value structure beneath the Tibet Plateau   总被引:1,自引:0,他引:1  
InversionofQvaluestructurebeneaththeTibetPlateauJIAN-PINGWU(吴建平)andRONG--SHENGZENG(曾融生)(InstitutefoGeophysicsStateSeismologic...  相似文献   

6.
ApracticalmodelforthepowerspectrumofspatialyvariantgroundmotionTIE-JUNQU1)(屈铁军),JUN-JIEWANG2)(王君杰)andQIAN-XINWANG1)(王前信)1)In...  相似文献   

7.
InfluencecausedbyinitialtectonicstresonrelativemeasurementofboreholegroundstresinviscoelasticmediaPENG-JUNZHAO1)(赵鹏君),JIAN-W...  相似文献   

8.
AnalternatealgorithmofnumericalsimulationinanisotropicmediaDING-HUIYANG(杨顶辉),JI-WENTENG(滕吉文)andZHONG-JIEZHANG(张中杰)Instituteo...  相似文献   

9.
LoadtideheatingmechanismofoceanichotspotsSHUN-LIANGCHI1)(池顺良),QIN-WENXI2)(郗钦文),MING-JINLUO3)(骆鸣津)andLIANGCHI1)(池亮)1)Seismolg...  相似文献   

10.
ConfinedaquiferaswaveguideanditsresponsestogeoacousticwavesWENBINJIAN1)(简文彬)BAORENCHEN2)(陈葆仁)HUAFULU2)(卢华复)1)Department...  相似文献   

11.
面向设计应用的地震动空间相干函数模型   总被引:1,自引:1,他引:1  
本文对现有的常用地震动空间相干模型进行了总结,提出了一个新的面向工程抗震设计应用的形式统一的地震动空间相干函数模型,在此基础上推导出了多点地震反应谱和功率谱计算所需要的振型组合系数的解析表达式,避免了耗费时间的数值积分运算。本文模型与计算方法使多点地震激励下结构响应的计算时间减低至积分方法的1/20以下,使多点地震反应谱方法和多点地震功率谱方法在计算时间方面实用化。  相似文献   

12.
本研究主要讨论地震动空间变化的随机描述.首先给出了基于密集地震台阵记录估计相干函数的方法,并对计算中需要关注的问题给出了相应的解释;然后对现有的经验和半经验相干函数模型的建立进行了详细的梳理,并对模型在工程应用中的适用性、有效性和局限性进行了讨论;最后通过对比分析不同相干函数模型对场址地震动空间相关性的模拟结果,对相干函数模型的选择提出了建议.  相似文献   

13.
14.
A spatial filter is often attached to a microphone or microbarometer in order to reduce the noise caused by atmospheric turbulence. This filtering technique is based on the assumption that the coherence length of turbulence is smaller than the spatial extent of the filter, and so contributions from turbulence recorded at widely separated ports will tend to cancel while those of the signal of interest, which will have coherence length larger than the spatial dimensions of the filter, will be reinforced. In this paper, the plane wave response for a spatial filter with an arbitrary arrangement of open ports is determined. It is found that propagation over different port-to-sensor distances causes out-of-phase sinusoids to be summed at the central manifold and can lead to significant amplitude decay and phase delays as a function of frequency. The determined spatial filter plane wave response is superimposed on an array response typical of infrasound arrays that constitute the International Monitoring System infrasound network used for nuclear monitoring purposes. It is found that signal detection capability in terms of the Fisher Statistic can be significantly degraded at certain frequencies. The least-squares estimate of signal slowness can change by up to 1.5° and up to 10 m/s if an asymmetric arrangement of low and high frequency spatial filters is used. However, if a symmetric arrangement of filters is used the least-squares estimate of signal slowness is found to be largely unaffected, except near the predicted null frequency.  相似文献   

15.
本文针对辽河特大桥项目进行了空间相关多点地震动合成的研究。在单点地震动合成的基础上,引入相干函数反应空间各点的相干性,用视波速反应行波效应,并通过matlab来实现。对4个输入点,进行了地震动合成。合成地震动反应谱与目标反应谱误差在5%以内。  相似文献   

16.
We present a new hybrid method combining deterministic and stochastic features. The aim is to describe the crustal propagation better than deterministic or stochastic methods can do separately. We start from the deterministic hybrid method based on Discrete- Wavenumber and Finite-Difference techniques (DW–FD). First we modify the DW–FD procedure by introducing topographical variations and a spatially varying Q factor. Then, to take into account effects due to small-scale heterogeneities of the crust, we add a stochastic noise (perturbation) to the deterministic signal propagated through the crust. The stochastic noise is constructed using a kind of Markov-like process generator with two physical constraints: to have the Brune spectrum, and to reproduce the spatial decay of coherence reported in literature for real sites. We have chosen a Markov-like technique because it allows us to get stochastic noise, with the given coherence spatial decay, directly in time domain. This new hybrid method is applied in a numerical test, the parameters of which approximate the case of the 12 June, 1995 Rome earthquake. It is found that the coherence decay with distance at the alluvial valley surface is slower than the prescribed coherence decay inside the bedrock.  相似文献   

17.
An examination was made into the spatial pattern of time-averaged streamwise velocity in the near-bed region over two water-worked gravel beds. Laboratory observations revealed that there is considerable spatial variability in velocity. It was organised into streamwise streaks of high-speed fluid which were overlain by spots of low-speed fluid. This spatial pattern was found to be consistently and heavily dependent on relative submergence. The spatial pattern of velocity was shown to have little linear coherence with bed surface topography at the grain-scale. It suggested that for flows above the two beds studied here, bed surface topography at the grain-scale exerted less of an influence on the spatial organisation of time-averaged streamwise velocities than relative submergence.  相似文献   

18.
The loss of coherence of seismic waves, even over small distances, can become significant and consequently important for engineering applications. This coherence loss depends on several parameters (frequency, inter-station distance), but their dependencies are not well understood yet. We show the results of a detailed analysis of the spatial variability of the coherence between two signals. This analysis is based on a simple model which is an exponential function of inter-station distance and frequency. Data from a temporary network of 36 weak-motion instruments installed at the EURO-SEISTEST site, north-east of Thessaloniki (Greece), is used in this work. The data offers the unique possibility to study the loss of coherence over a wide range of distances, as the inter-station distances are between 8 m and 5488 m. We test the influence on the coherence of the length of the time-window of the signals, of the type of the waves present in the time-window and of the common energy of the signals. We also show that, at least at this particular site, the loss of coherence with distance is probably marked by a "cross over" distance, distinguishing two different ranges: one for inter-station distances up to 100 m and the other above 100 m. Finally, we find that the coherence determined from noise recordings behaves in a rather similar way to the one determined from coda-waves and more stationary (longer) signals. Therefore, noise can be useful for a rough, but quick estimation of the loss of coherence, at least for inter-station distances larger than 100 m.  相似文献   

19.
大跨度空间网格结构多维多点随机地震反应分析   总被引:4,自引:0,他引:4  
本文建立了三维正交地震动多点激励下大跨度空间网格结构的随机地震反应分析方法,依据现行抗震设计规范的有关规定,确定了平稳随机地震动功率谱密度的模型参数。数值仿真分析了一柱距80m的正方形平板网架分别在一维地震动或三维地震动的一致激励、行波激励和考虑部分相干效应的随机激励下的地震反应。结果表明:考虑地震动的空间效应会很大程度地改变结构杆件的内力,其中控制杆件的内力增幅达到30%;地震动的行波效应对结构杆件内力的影响比随机地震动的部分相干效应的影响更大;三维地震作用比一维地震作用下结构杆件的内力大。由此得出结论,对于大跨度空间网格结构,必须进行多维多点地震激励下的随机地震反应分析。  相似文献   

20.
刘财  刘海燕  彭冲  张营  刘琼  勾福岩 《地球物理学报》2016,59(10):3859-3868
突出地震数据振幅空间不连续性的断层增强属性体是断层自动解释的基础,而如何压制噪声、地层残余响应、角度不整合接触等伪断层的影响是断层自动检测的关键问题之一.在指纹图像边缘检测处理中,一致性是对指示局部方向场信息各向异性强度的一个度量,本文将其作为一种新的断层增强属性引入到地震数据处理中.为了更有效地压制噪声,本文通过对一致性进行加权处理,再结合蚁群算法,提出了新的断层自动检测方法——基于加权一致性的蚁群算法.理论地震模型和实际地震数据的处理结果表明,对于相同的断层检测过程,对比常规的基于方差属性的蚁群算法和基于C3相干属性的蚁群算法,本文所提方法不仅更有效地压制了噪声和地层残余响应产生的伪断层信息,而且更完整地展现了断层的延伸长度,同时具有更高的稳定性和计算效率.  相似文献   

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