基于MED的探地雷达信号处理研究          下载免费PDF全文

邹明阳  阎长虹  段成龙  吴焕然  徐杨 《高校地质学报》2014,20(3):482

   文中运用改进的最小熵反褶积（MED） 理论,采用MATLAB编写程序,实现了改进的MED计算机自动处理功能。将 其应用到在建中的某地铁4号线某区间的探地雷达资料处理中,较准确地确定了岩溶的位置和尺寸。将处理结果与钻孔岩 芯资料进行比照,发现雷达探测结果与钻探结果具有较好的一致性,表明MED方法能在雷达剖面上有效显示溶洞位置,该 项研究成果对类似工程具有重要借鉴意义。  相似文献   

基于重力垂直梯度的欧拉反褶积改进措施     

吴亮  王庆宾  常岑 《大地测量与地球动力学》2016,36(3):193-197

欧拉反褶积反演解的发散与不稳定性一直制约着其实用效果。为此,提出利用垂直梯度反演和筛选准则并在分辨信号极值区域基础上进行重力反演等改进方法。通过模型试算,全面分析它们相对常规重力数据反演方法的效果。结果表明,改进方法能明显提高反演解水平位置和深度的精度和收敛性。  相似文献   

Inversion of potential field data using the structural index as weighting function rate decay   总被引：1，自引：0，他引：1  

Federico Cella  Maurizio Fedi 《Geophysical Prospecting》2012,60(2):313-336

Nonparametric inverse methods provide a general framework for solving potential‐field problems. The use of weighted norms leads to a general regularization problem of Tikhonov form. We present an alternative procedure to estimate the source susceptibility distribution from potential field measurements exploiting inversion methods by means of a flexible depth‐weighting function in the Tikhonov formulation. Our approach improves the formulation proposed by Li and Oldenburg (1996, 1998) , differing significantly in the definition of the depth‐weighting function. In our formalism the depth weighting function is associated not to the field decay of a single block (which can be representative of just a part of the source) but to the field decay of the whole source, thus implying that the data inversion is independent on the cell shape. So, in our procedure, the depth‐weighting function is not given with a fixed exponent but with the structural index N of the source as the exponent. Differently than previous methods, our choice gives a substantial objectivity to the form of the depth‐weighting function and to the consequent solutions. The allowed values for the exponent of the depth‐weighting function depend on the range of N for sources: 0 ≤N≤ 3 (magnetic case). The analysis regarding the cases of simple sources such as dipoles, dipole lines, dykes or contacts, validate our hypothesis. The study of a complex synthetic case also proves that the depth‐weighting decay cannot be necessarily assumed as equal to 3. Moreover it should not be kept constant for multi‐source models but should instead depend on the structural indices of the different sources. In this way we are able to successfully invert the magnetic data of the Vulture area, Southern Italy. An original aspect of the proposed inversion scheme is that it brings an explicit link between two widely used types of interpretation methods, namely those assuming homogeneous fields, such as Euler deconvolution or depth from extreme points transformation and the inversion under the Tikhonov‐form including a depth‐weighting function. The availability of further constraints, from drillings or known geology, will definitely improve the quality of the solution.  相似文献   

地震频发区域背景噪声提取格林函数的反褶积方法研究   总被引：1，自引：0，他引：1  

庞卫东  杨润海  郑定昌  刘娜  沈娅宏 《地震研究》2012,35(1):29-35,157

针对云南这一地震频发区域记录到的地震背景噪声数据,设计了一种"最大值均一化"算法,该算法能有效地消除背景噪声中的地震信号、畸变信号及其它干扰信号。应用此算法对记录到的背景噪声数据进行预处理,对处理后的数据利用多窗谱反褶积计算方法可获得其具有较高信噪比和保留了相对幅值信息的格林函数。  相似文献   

新型高分辨率自然伽马测井仪器的优化设计与资料处理技术   总被引：1，自引：0，他引：1  

陶宏根  商庆龙  刘长伟  汪宏年  李舟波 《吉林大学学报(地球科学版)》2012,42(4):906-913

通过自然伽马响应函数与其探测器长度间关系的研究,选择长度为0.1 m的NaI晶体作为新型高分辨率自然伽马仪器的探测器。为克服短NaI晶体会导致计数率降低和统计涨落误差增大等问题,利用4个大小完全相同的NaI晶体同时测量伽马射线强度,获得4条高分辨率自然伽马测井曲线;然后,对4条测量曲线进行累加并结合带通滤波技术充分降低统计涨落误差;在此基础上,进一步应用正则化反褶积处理提高仪器的纵向分辨率。理论模型和井场试验结果均证明,该新型高分辨率伽马仪器具有0.15 m的纵向分辨率,比常规自然伽马测井仪器的分辨率提高了4倍以上。  相似文献   

利用接收函数研究鄂尔多斯东缘地壳上地幔结构     

黄韬  米宁  王良书  徐鸣洁  李华  于大勇 《高校地质学报》2011,17(4):569-576

       由1876个远震三分量P波地震图组成的数据集,取自布置于鄂尔多斯-太行山一线的宽频带流动台站。通过阵列反 卷积方法,得到地下界面响应的接收函数,并通过共转换点偏移叠加得到地下结构的图像。图像显示,从鄂尔多斯至渤海 湾盆地地壳厚度总体上逐渐变薄,Moho面总体呈小角度向西倾斜。鄂尔多斯块体中部地壳最厚,达到52 km,向东到鄂尔多 斯边缘,地壳厚度减小至43 km。太行山至渤海湾盆地地壳厚度从45 km减小至37 km。山西地堑下方Moho面上隆,和两边的 Moho面相比,抬升8~10 km,且其Moho面的上隆和新生代地堑的凹陷呈镜像关系。  相似文献   

Estimating the Earthquake Source Time Function by Markov Chain Monte Carlo Sampling     

Wojciech Dȩbski 《Pure and Applied Geophysics》2008,165(7):1263-1287

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地震偏移反演成像的迭代正则化方法研究   总被引：12，自引：7，他引：5       下载免费PDF全文

王彦飞  杨长春  段秋梁 《地球物理学报》2009,52(6):1615-1624

利用伴随算子L^*,直接的偏移方法通常导致一个低分辨率或模糊的地震成像.线性化偏移反演方法需求解一个最小二乘问题.但直接的最小二乘方法的数值不稳定,为目视解译带来困难.本文建立约束正则化数学模型,研究了地震偏移反演成像问题的迭代正则化求解方法.首先对最小二乘问题施加正则化约束,接着利用梯度迭代法求解反演成像问题,特别是提出了共轭梯度方法的混合实现技巧.为了表征该方法的可实际利用性,分别对一维,二维和三维地震模型进行了数值模拟.结果表明该正则偏移反演成像方法是有效的,对于实际的地震成像问题有着良好的应用前景.  相似文献   

海上多次波的联合衰减法   总被引：1，自引：0，他引：1       下载免费PDF全文

王建立  王真理  张洪宙  方正茂  李学良  杨长春 《地球物理学进展》2009,24(6):2070-2078

地震勘探尤其是海上地震勘探中存在着各类多次波,由于多次波的存在严重影响了速度分析、叠加、偏移成像等地震资料处理,海上多次波主要有全程多次波和层间多次两大类,为了压制海上不同类型的多次波,本文首先分析波场外推、预测反褶积和拉东变换衰减不同多次波的理论基础,然后联合采用这些方法,分别衰减全程多次波和层间多次波;即：首先对炮记录或者接收点记录进行波场外推,建立海底多次波模型,预测并减去全程多次波,然后利用预测反褶积衰减掉周期性明显的多次波,最后将数据转换到τ-p域,用拉冬变换根据同一时间多次波和有效波在速度等方面的差异,进一步分离层间多次波和剩余的全程多次波,并在该域中切除分离出的多次波,从而实现联合多次波衰减处理.通过对悉尼海区和里海等实际地震资料的处理证明,文提出的联合多次波衰减方法在海洋地震资料的处理中有着广泛的应用,联合衰减多次波处理流程具有快速、简洁、易于实现的特点,经处理后的地震资料有效信号损失小、保福性好的特点,有利于速度分析、叠加、叠前偏移等的后续处理工作.  相似文献   

Problematic non-double-couple mechanism of the 2002 Amfilochia Mw5 earthquake, Western Greece     

Petra Adamova  Efthimios Sokos  Jiri Zahradnik 《Journal of Seismology》2009,13(1):1-12

Two seismic agencies reported a very low double-couple percentage (DC%) of the Amfilochia earthquake, of about 30% and 60%, by Schweizerischer Erdbebendienst and Mediterranean Very Broadband Seismographic Network, respectively. Near-regional waveforms, carefully analyzed in this paper for the DC%, suggested a higher DC%, ranging from 75 to 100, dependent on the uncertainty of the source position (optimum value DC% = 93). Using a statistical F test, forward modeling of the near-regional data with a single-event low-DC% source yields a significantly worse waveform match. The fit of near-regional data can be further improved (although at the 90% significance level only) when considering a speculative two-event model. The same model, when viewed at the very-low frequency range, reaches the very low DC% values. However, two features make the two-event model unlikely: The two subevents strongly differ in their focal mechanism, and their mutual separation (3.5 s) is larger than the expected duration of this earthquake. Therefore, the two-source model appears to be nothing but an interesting equivalent representation of the non-DC model, providing some insight into the possible origin of the apparently low DC%. Preference is given to the simple interpretation, most clearly supported by the near-regional data, that the Amfilochia earthquake was an almost pure-shear event.  相似文献