长白山天池火山区大地电磁测深初步观测   总被引：24，自引：7，他引：24       下载免费PDF全文

汤吉  刘铁胜 《地震地质》1997,19(2):69-170

在长白山火山区沿着两条剖面进行了１５个测点的大地电磁测深观测，对地磁感应矢量和地下电性分布维数特征进行了分析，并使用阻抗张量分解和二维自动反演等新技术对资料进行了解释。结果表明，火山区及其周围地区的地下电性结构具有二维特征，但在火山口及其附近地下存在局部三维异常体，异常体埋深约１２ｋｍ，初步推测可能是火山岩浆囊  相似文献   

表面局部三维大地电磁曲线畸变校正——MT畸变校正阻抗张量分解方法   总被引：3，自引：0，他引：3       下载免费PDF全文

王书明 《地震工程学报》1998,20(4):1-11

针对三维／二维地质结构开发了大地电磁阻抗张量分解技术,利用该技术仅需对各个独立测点的大地电磁资料进行分析即可分离和消除由三维局部异常体引起的其附近测点的ＭＴ响应函数的形态扭曲畸变。  相似文献   

大地电磁(MT)阻抗张量的正则分解及其初步应用   总被引：5，自引：0，他引：5       下载免费PDF全文

晋光文  孙洁 《地震地质》1998,20(3):52-249

鉴于大地电磁阻抗张量传统分析方法的局限性,提出了普遍适用的正则分解方法。在用正则分解方法分析时,主坐标系提供的８个标量参数,描述了地球系统传输特性和场源极化状态及其联系,因此是物理意义明确、易于解释的参数体系。讨论了正则分解方法在各种构造条件下的特点和场源的极化问题,并给出了简单的应用实例  相似文献   

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties     

Arne Schnack-Friedrichsen  Angela M. Davis  Jim D. Bennell  Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243

The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.  相似文献   

大地坐标系应变张量表达及其与地心直角坐标系的相互转换     

季颖锋  刘序俨  李祖宁  黄声明  钟继茂  陈光 《华南地震》2010,30(2):67-78

推导并给出了不同正交曲线坐标系应变张量和转动张量的普适表达和在旋转椭球坐标系下的应变张量表达,给出了不同正交曲线坐标系之间应变张量转换的普适表达式,以及在大地坐标系与地心直角坐标系这两种坐标系之间应变张量矩阵相互转换的具体表达,可供实际研究工作应用。  相似文献   

弹性波阻抗反演在煤层气储层预测中的应用     

程彦  张华  王敏 《煤田地质与勘探》2011,39(2):70-73

弹性波阻抗反演方法保留了地震反射振幅随偏移距或入射角变化的特征,能够获得更多、更敏感、更有效的数据,不但适合地层反演,还可进行储集层岩性反演。阐述了弹性波阻抗反演的基础理论及实现流程,通过对实际资料的反演,分析了其在煤层气储层预测中的应用特点。   相似文献   

100Hz～10MHz频段含油水两相岩石电阻抗的研究   总被引：4，自引：1，他引：3  

苏庆新  柯式镇 《地球物理学进展》1999,14(1):93-103

本项研究应用两电极法扫描测量了２２块岩样的油驱水过程中电阻抗的变化,实验表明,在低频段（１００Ｈｚ～１０ＭＨｚ）岩石的电阻抗虚部能较好地反映岩石含水饱和度的变化,岩石的界面极化频率及其对应的电阻抗实部,虚部与岩石的含水饱和度有较密切的关系,可以用来确定岩石的含水饱和度,岩样阻抗的实部和虚部的Ａｒｇａｎｄ图中的低端临界频率随着含水饱和度的变化而变,这表明低端临界频率不仅取愉于岩石的特征长度√ｋ／Φ（  相似文献   

Seismic base-isolation mechanism in liquefied sand in terms of energy     

《Soil Dynamics and Earthquake Engineering》2014

Seismic base isolation effect in a liquefied sand layer was investigated based on soil properties measured in a series of undrained cyclic triaxial tests. Transmission of seismic wave in a soil model consisting of a liquefied surface layer and an underlying nonliquefied layer was analyzed in terms of energy, considering liquefaction-induced changes in S-wave velocity and internal damping. It was found that, between two different base-isolation mechanisms, a drastic increase in wave attenuation in the liquefied layer due to shortening wave length gives a greater impact on the base isolation with increasing thickness of the liquefied layer than the change of seismic impedance between the liquefied and nonliquefied layer. Also indicated was that cyclic mobility behavior in dilative clean sand tends to decrease the seismic isolation effect to a certain extent.  相似文献   

Vertical and horizontal vibrations of a rigid disc on a multilayered transversely isotropic half-space     

《Soil Dynamics and Earthquake Engineering》2014

A half-space containing horizontally multilayered regions of different transversely isotropic elastic materials as well as a homogeneous half-space as the lowest layer is considered such that the axes of material symmetries of different layers and the lowest half-space to be as depth-wise. A rigid circular disc rested on the free surface of the whole half-space is considered to be under a forced either vertical or horizontal vibration of constant amplitudes. Because of the involved integral transforms, the mixed boundary value problems due to mixed condition at the surface of the half-space are changed to some dual integral equations, which are reduced to Fredholm integral equations of second kind. With the help of contour integration, the governing Fredholm integral equations are numerically solved. Some numerical evaluations are given for different combinations of transversely isotropic layers to show the effect of degree of anisotropy of different layers on the response of the inhomogeneous half-space.  相似文献   

大地电磁资料精细处理和二维反演解释技术研究（四）——阻抗张量分解的多测点-多频点统计成像分析   总被引：6，自引：5，他引：1       下载免费PDF全文

陈小斌  蔡军涛  王立凤  叶涛 《地球物理学报》2014,57(6):1946-1957

基于大地电磁阻抗张量分解技术,本文提出了两种电性主轴方位的统计描述图像：随频率变化的统计分布成像（频率分布云图）和随测点序列变化的统计分布成像（测点分布云图）.这两种图像与传统的统计玫瑰图一起,较全面地描述了最佳主轴的分布特征.在进行构造维性分析过程中,通过定义二维有效因子e_2d,来压制一维结构和三维结构、突出纯二维结构的影响.e_2d被用于电性主轴的统计加权,有效地起到了滤波的作用;同时,统计成像中还考虑了数据质量的影响.为了得到稳定、高质量的区域阻抗张量数据,提出并实现了共主轴的多测点-多频点阻抗张量分解新算法.最终,完成了以上各项处理手段的可视化实现.本文通过两个理论模型和一个实测算例,以共轭阻抗法（CCZ法）为基础,展示了这一新技术的有效性.  相似文献