Sonification of geophysical data through time–frequency analysis: theory and applications          下载免费PDF全文

Paolo Dell'Aversana  Gianluca Gabbriellini  Alfonso Amendola 《Geophysical Prospecting》2017,65(1):146-157

In this paper, we introduce a new method of geophysical data interpretation based on simultaneous analysis of images and sounds. The final objective is to expand the interpretation workflow through multimodal (visual–audio) perception of the same information. We show how seismic data can be effectively converted into standard formats commonly used in digital music. This conversion of geophysical data into the musical domain can be done by applying appropriate time–frequency transforms. Using real data, we demonstrate that the Stockwell transform provides a very accurate and reliable conversion. Once converted into musical files, geophysical datasets can be played and interpreted by using modern computer music tools, such as sequencers. This approach is complementary and not substitutive of interpretation methods based on imaging. It can be applied not only to seismic data but also to well logs and any type of geophysical time/depth series. To show the practical implications of our integrated visual–audio method of interpretation, we discuss an application to a real seismic dataset in correspondence of an important hydrocarbon discovery.  相似文献   

海底地震仪的信号传递效果和噪声水平          下载免费PDF全文

王笋  丘学林  赵明辉  李普春  刘丽华  张艺峰  谢志招 《地球物理学报》2019,62(8):3199-3207

单球式海底地震仪（以下简称OBS）由于其成本低、操作简便的优点在天然地震研究、人工地震探测中获得了广泛应用.本文首先分析多型进口和国产OBS在台湾海峡西部采集的地震数据,发现同一台OBS上的垂直向速度检波器（Z分量）的信噪比常显著低于压力检波器（H分量）,由于这两种检波器记录的都是海底的垂向振动信号,推测速度检波器的低信噪比更多的与仪器特性有关.然后从信号传递和噪声水平两方面分析影响速度检波器信噪比的因素：为检测速度检波器与OBS壳体的耦合效果,对某型宽频带OBS和陆上地震仪进行了同址同步观测试验,发现OBS的整机灵敏度有较大的差异;为分析速度检波器的水底噪声特征,以H分量记录作为基准,对比分析了同一台仪器不同站位的Z分量噪声水平,发现速度检波器在浅海区受到较大的次生干扰.本文指出OBS的内部耦合和水流次生干扰是至今尚未引起大家重视而又严重影响资料品质和多波探测成效的两个关键问题,这一研究结果对于改进OBS结构设计和制造工艺,以及OBS数据多分量处理方法研究有重要的参考意义.  相似文献   

Widely linear denoising of multicomponent seismic data     

Breno Bahia  Mauricio D. Sacchi 《Geophysical Prospecting》2020,68(2):431-445

Seismic data processing is a challenging task, especially when dealing with vector-valued datasets. These data are characterized by correlated components, where different levels of uncorrelated random noise corrupt each one of the components. Mitigating such noise while preserving the signal of interest is a primary goal in the seismic-processing workflow. The frequency-space deconvolution is a well-known linear prediction technique, which is commonly used for random noise suppression. This paper represents vector-field seismic data through quaternion arrays and shows how to mitigate random noise by proposing the extension of the frequency-space deconvolution to its hypercomplex version, the quaternion frequency-space deconvolution. It also shows how a widely linear prediction model exploits the correlation between data components of improper signals. The widely linear scheme, named widely-linear quaternion frequency-space deconvolution, produces longer prediction filters, which have enhanced signal preservation capabilities shown through synthetic and field vector-valued data examples.  相似文献   

A numerical study on deblending of land simultaneous shooting acquisition data via rank-reduction filtering and signal enhancement applications     

Woodon Jeong  Constantinos Tsingas  Mohammed S. Almubarak 《Geophysical Prospecting》2020,68(6):1742-1757

We propose a workflow of deblending methodology comprised of rank-reduction filtering followed by a signal enhancing process. This methodology can be used to preserve coherent subsurface reflections and at the same time to remove incoherent and interference noise. In pseudo-deblended data, the blending noise exhibits coherent events, whereas in any other data domain (i.e. common receiver, common midpoint and common offset), it appears incoherent and is regarded as an outlier. In order to perform signal deblending, a robust implementation of rank-reduction filtering is employed to eliminate the blending noise and is referred to as a joint sparse and low-rank approximation. Deblending via rank-reduction filtering gives a reasonable result with a sufficient signal-to-noise ratio. However, for land data acquired using unconstrained simultaneous shooting, rank-reduction–based deblending applications alone do not completely attenuate the interference noise. A considerable amount of signal leakage is observed in the residual component, which can affect further data processing and analyses. In this study, we propose a deblending workflow via a rank-reduction filter followed by post-processing steps comprising a nonlinear masking filter and a local orthogonalization weight application. Although each application shows a few footprints of leaked signal energy, the proposed combined workflow restores the signal energy from the residual component achieving significantly signal-to-noise ratio enhancement. These hierarchical schemes are applied on land simultaneous shooting acquisition data sets and produced cleaner and reliable deblended data ready for further data processing.  相似文献   

Spatially constrained attenuation compensation in the mixed domain     

Xiong Ma  Guofa Li  Shumei He  Hao Li  Zhewu Wang 《Geophysical Prospecting》2020,68(6):1819-1833

Seismic attenuation compensation is a spectrum-broadening technique for enhancing the resolution of non-stationary seismic data. The single-trace attenuation compensation algorithms ignore the prior information that the seismic reflection events are generally continuous along seismic traces, thus, the compensated result may have poor spatial continuity and low signal-to-noise ratio. To address this problem, we extend the single-trace approaches to the multi-trace algorithms and furthermore propose a multi-trace attenuation compensation with a spatial constraint. The frequency-space prediction filters are the key to construct this spatial regularization. We test the effectiveness of the proposed spatially constrained attenuation compensation algorithm by applying both synthetic and field data examples. Synthetic data tests indicate that the proposed multi-trace attenuation compensation approach can provide a better compensated result than single-trace attenuation compensation algorithm in terms of suppressing noise amplification and guaranteeing structural continuities. Field data applications further confirm its stability and practicality to improve seismic resolution.  相似文献   

Windowless Q-factor tomography by the instantaneous frequency     

A. Vesnaver  G. Böhm  P. Cance  M. Dal Cin  D. Gei 《Geophysical Prospecting》2020,68(9):2611-2636

The estimation of the Q factor of rocks by seismic surveys is a powerful tool for reservoir characterization, as it helps detecting possible fractures and saturating fluids. Seismic tomography allows building 3D macro-models for the Q factor, using methods as the spectral ratio and the frequency shift. Both these algorithms require windowing the seismic signal accurately in the time domain; however, this process can hardly follow the continuous variations of the wavelet length as a function of offset and propagation effects, and it is biased by the interpreter choice. In this paper, we highlight some drawback of signal windowing in the frequency-shift method, and introduce a tomographic approach to estimate the Q factor using the complex attributes of the seismic trace. We show that such approach is particularly needed when the dispersion is broadening the waveforms of signals with a long wave-path. Our method still requires an interpretative event picking, but no other parameters as the time window length and its possible smoothing options. We validate the new method with synthetic and real data examples, involving the joint tomographic inversion of direct and reflected signals. We show that a calibration of the frequency-shift method is needed to improve the estimation of the absolute Q factor, otherwise only relative contrasts are obtained.  相似文献   

Improved structural interpretation of legacy 3D seismic data from Karee platinum mine (South Africa) through the application of novel seismic attributes     

Musa S.D. Manzi  Gordon R.J. Cooper  Alireza Malehmir  Raymond J. Durrheim 《Geophysical Prospecting》2020,68(1):145-163

Seismic detection of faults, dykes, potholes and iron-rich ultramafic pegmatitic bodies is of great importance to the platinum mining industry, as these structures affect safety and efficiency. The application of conventional seismic attributes (such as instantaneous amplitude, phase and frequency) in the hard-rock environment is more challenging than in soft-rock settings because the geology is often complex, reflections disrupted and the seismic energy strongly scattered. We have developed new seismic attributes that sharpen seismic reflections, enabling additional structural information to be extracted from hard-rock seismic data. The symmetry attribute is based on the invariance of an object with respect to transformations such as rotation and reflection; it is independent of the trace reflection amplitude, and hence a better indicator of the lateral continuity of thin and weak reflections. The reflection-continuity detector attribute is based on the Hilbert transform; it enhances the visibility of the peaks and troughs of the seismic traces, and hence the continuity of weak reflections. We demonstrate the effectiveness of these new seismic attributes by applying them to a legacy 3D seismic data set from the Bushveld Complex in South Africa. These seismic attributes show good detection of deep-seated thin (∼1.5 m thick) platinum ore bodies and their associated complex geological structures (faults, dykes, potholes and iron-rich ultramafic pegmatites). They provide a fast, cost-effective and efficient interpretation tool that, when coupled with horizon-based seismic attributes, can reveal structures not seen in conventional interpretations.  相似文献   

数字天气雷达虚拟终端的硬件和软件设计     

赵坤  陈建军  方德贤  葛文忠  慕熙昱 《高原气象》2006,25(2):335-343

设计了一套基于PC机的数字天气雷达虚拟终端系统,用普通的PC机代替传统数字天气雷达信号处理分机[1,2]直接完成雷达信号处理和实时显示。该系统在硬件方面,设计了基于PCI总线的三通道高速数据接收卡,以满足大容量数据高速传输要求;在软件方面则利用高级语言(C )和虚拟设备驱动程序(WDM)技术开发了一套基于WINDOWS2000/9X操作系统的实时处理软件,以此控制数据接收卡和雷达工作,并完成信号处理和实时显示。实际应用表明,该系统结构简单、界面友好、操作方便、便于升级,完全能够实时、高效地处理常规天气雷达信号,而且处理后的雷达回波层次清楚,具有较高精度。本研究也为虚拟终端应用到多普勒天气雷达打下了一个良好的基础。  相似文献   

3D Marchenko applications: implementation and examples     

Joeri Brackenhoff  Jan Thorbecke  Giovanni Meles  Victor Koehne  Diego Barrera  Kees Wapenaar 《Geophysical Prospecting》2022,70(1):35-56

We implement the 3D Marchenko equations to retrieve responses to virtual sources inside the subsurface. For this, we require reflection data at the surface of the Earth that contain no free-surface multiples and are densely sampled in space. The required 3D reflection data volume is very large and solving the Marchenko equations requires a significant amount of computational cost. To limit the cost, we apply floating point compression to the reflection data to reduce their volume and the loading time from disk. We apply the Marchenko implementation to numerical reflection data to retrieve accurate Green's functions inside the medium and use these reflection data to apply imaging. This requires the simulation of many virtual source points, which we circumvent using virtual plane-wave sources instead of virtual point sources. Through this method, we retrieve the angle-dependent response of a source from a depth level rather than of a point. We use these responses to obtain angle-dependent structural images of the subsurface, free of contamination from wrongly imaged internal multiples. These images have less lateral resolution than those obtained using virtual point sources, but are more efficiently retrieved.  相似文献   

以格点尝试法求取的山东地区现代中小地震震源机制解   总被引：12，自引：0，他引：12  

周翠英  华爱军  蒋海昆  董旭光  吴延河  张玲  侯海峰 《东北地震研究》2003,19(1):1-11

搜集和整理了1970年以来山东及近邻区域地震台网记录的近展和地方展的P波初动方向资料，以格点尝试法计算求取了该区1970年至2001年的102组中小地震单展震源机制解和部分台站及小区域综合机制解结果。为了解以往手工求解的机制解结果与此次计算结果的差异与否，做了部分资料的手工与计算结果的对比分析。最后依据这些资料对山东地区现今中小地震的破裂机制进行了分析讨论。  相似文献