Journal articles on the topic 'Seismology and Seismic Exploration'
To see the other types of publications on this topic, follow the link: Seismology and Seismic Exploration.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Seismology and Seismic Exploration.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Davis, Thomas L. "Multicomponent seismology—The next wave." GEOPHYSICS 66, no. 1 (January 2001): 49. http://dx.doi.org/10.1190/1.1444920.
Full textAbstract:
Multicomponent seismology requires recording of seismic data with three‐ and sometimes four‐component receivers. The three components measure displacement of the ground, usually in two horizontal and one vertical directions. The fourth component is a measurement of pressure, which is used in sea‐bottom surveys. Measuring three components of ground displacement enables the recording of compressional (P) and shear (S) waves which represent the full complement of “body” waves in seismology. Earthquake seismologists have been using the full complement for years to interpret the structure of our living planet; however, exploration seismologists have been slow to bring multicomponent seismology to the forefront of their measurement system. This is finally changing. Thanks to new seismic acquisition recording systems, it is now feasible to economically record multicomponent seismic data in both land and marine (sea‐bottom) settings. In the future, all land or sea‐bottom seismic data will be recorded by multicomponent technology, thereby bringing us the next wave of exploration geophysics as we begin to “see the unseen.”
2
Wang, Zhijing (Zee). "Fundamentals of seismic rock physics." GEOPHYSICS 66, no. 2 (March 2001): 398–412. http://dx.doi.org/10.1190/1.1444931.
Full textAbstract:
During the past 50 years or so, tremendous progress has been made in studying physical properties of rocks and minerals in relation to seismic exploration and earthquake seismology. During this period, many theories have been developed and many experiments have been carried out. Some of these theories and experimental results have played important roles in advancing earth sciences and exploration technologies. This tutorial paper attempts to summarize some of these results.
3
GAUZELLINO, PATRICIA M., JUAN E. SANTOS, and DONGWOO SHEEN. "FREQUENCY DOMAIN WAVE PROPAGATION MODELING IN EXPLORATION SEISMOLOGY." Journal of Computational Acoustics 09, no. 03 (September 2001): 941–55. http://dx.doi.org/10.1142/s0218396x01000917.
Full textAbstract:
To evaluate the wavefield for realistic 2-D and 3-D models we used a parallel computer, employing algorithms designed specifically to profit from the parallel architecture. The numerical procedures are iterative domain decomposition algorithms employing a nonconforming finite element, which are used to discretize the viscoacoustic and viscoelastic wave equations describing wave propagation in a porous medium saturated by either a single-phase or a two-phase compressible inviscid fluid and subject to absorbing boundary conditions at the artificial boundaries. Our purpose is to establish the effect of gas, brine or oil and gas-brine or gas-oil pore fluids on seismic velocities. Numerical examples showing the implementation of the algorithm to compute crosshole seismic response of simple 2-D and 3-D hydrocarbon reservoirs are presented.
4
Pang, Yao, Lijun Yan, Yuan Liu, Lin Tang, Rui Zhu, and Guofeng Liu. "Seismic Wave Finite-Difference Forward Modeling for Orogenic Gold Deposits." Minerals 12, no. 11 (November 19, 2022): 1465. http://dx.doi.org/10.3390/min12111465.
Full textAbstract:
The demand for deep prospecting has led to an increase in the enthusiasm for seismic techniques in mineral exploration. Reflection seismology applications in the base metal industry have achieved success. For orogenic gold deposits, however, their applicable conditions remain to be investigated. This paper simulated seismic wave propagation based on a finite-difference algorithm with an accuracy of eighth order in space and second order in time to investigate the factors influencing the reflection seismic exploration results. Then, the paper assessed the algorithm’s feasibility for orogenic gold deposits, taking the giant Zaozigou deposit in central China as an example. The forward modeling showed that the petrophysical properties, dimensions, and dip of targets significantly affected the seismic exploration results. In the Zaozigou model, shallowly dipping orebodies were well imaged with precise extension and thickness. Steeply dipping orebodies were recognized but their thickness information was lost. Steeply dipping orebodies at depth were not detectable under a surface configuration. These problems could be effectively solved by increasing the array length and using vertical seismic profiling methods. For small orebodies, multiwave and multicomponent seismic techniques offered more valuable information in terms of mineral exploration. In conclusion, it was possible to locate orogenic gold deposits using the reflection seismology method.
5
Schmelzbach, Cedric, Stefanie Donner, Heiner Igel, David Sollberger, Taufiq Taufiqurrahman, Felix Bernauer, Mauro Häusler, Cédéric Van Renterghem, Joachim Wassermann, and Johan Robertsson. "Advances in 6C seismology: Applications of combined translational and rotational motion measurements in global and exploration seismology." GEOPHYSICS 83, no. 3 (May 1, 2018): WC53—WC69. http://dx.doi.org/10.1190/geo2017-0492.1.
Full textAbstract:
Over the past few decades, the potential of collocated measurements of 6C data (3C of translational and 3C of rotational motion) has been demonstrated in global seismology using high-sensitivity, observatory-based ring laser technology. Proposed applications of 6C seismology range from tomographic reconstruction of near-receiver structure to the reduction of nonuniqueness in seismic source inverse problems. Applications to exploration problems have so far been hampered by the lack of appropriate sensors, but several applications have been proposed and demonstrated with array-derived rotational motion estimates. With the recent availability of, for example, fiber-optic-based high-sensitivity rotational motion sensors, widespread applications of 6C techniques to exploration problems are in sight. Potential applications are based on, for example, the fact that the extended set of combined translational and rotational motion observations enables carrying out array-type processing with single-station recordings such as wavefield separation and surface-wave suppression. Furthermore, measuring the rotational component (curl) of the seismic wavefield enables direct isolation of the S-wave constituents and could significantly improve S-wave exploration. Rotational measurements provide estimates of the spatial wavefield gradient at the free surface that allow carrying out analyses such as local slowness estimation and wavefield reconstruction. Furthermore, rotational motion measurements can help to resolve wavefield infidelity introduced by seismic instruments that are not well-coupled to the ground.
6
Thomas, José Eduardo. "Multichannel estimate of the seismic wavelet." GEOPHYSICS 51, no. 3 (March 1986): 838–43. http://dx.doi.org/10.1190/1.1442136.
Full textAbstract:
One of the fundamental problems in exploration seismology is to obtain a seismic record which has both high resolution and high ratio of signal to noise. If the seismic trace has a fair signal‐to‐noise (S/N) ratio, then subsequent data processing can be applied to improve the resolution. Basically, this data‐processing technique is the deconvolution of the source wavelet from the field seismic traces.
7
Malischewsky, Peter. "Seismic tomography. With applications in global seismology and exploration geophysics." Tectonophysics 172, no. 3-4 (February 1990): 369–70. http://dx.doi.org/10.1016/0040-1951(90)90043-8.
Full text
8
Aleksandrov, Vadim, Marsel Kadyrov, Andrey Ponomarev, Denis Drugov, and Evgeniya Neelova. "Using Borehole Seismic Data in Designing of Development and Further Exploration of Oil Fields." Key Engineering Materials 785 (October 2018): 20–26. http://dx.doi.org/10.4028/www.scientific.net/kem.785.20.
Full textAbstract:
Borehole seismology allows studying the specific features of the geological structure and physical properties of deposits in the borehole environment using waves of various kinds based on the analysis of characteristics of these waves, their rates propagation, attenuation, space polarization, and the nature of rock anisotropy. The research is intended to study the wave fields of various types of waves taking into account their dynamic, speed and polarization characteristics and the features of geological structure both in the vicinity to the borehole and laterally in the crosshole space. Using the borehole seismology method, the geological structure of reservoirs was specified; a prediction was given as to the development of enhanced reservoir units in the crosshole space.
9
Aharchaou, Mehdi, Ramesh (Neelsh) Neelamani, and Chengbo Li. "Introduction to this special section: Seismic resolution." Leading Edge 42, no. 1 (January 2023): 7. http://dx.doi.org/10.1190/tle42010007.1.
Full textAbstract:
The science of modern seismology was born more than 100 years ago (1889) when the first teleseismic record was identified and the seismograph was developed ( Ben-Menahem, 1995 ). In 1921, earth exploration was revolutionized when a team led by Clarence Karcher conducted the first field tests of the reflection seismograph in Oklahoma City ( Dragoset, 2005 ). That experiment showed that the subsurface can be imaged using seismic data. Businesses boomed as the seismic method started establishing its track record in finding hydrocarbons. Over the last century, the seismic method has emerged as the cornerstone of exploration geophysics, providing us with increasingly accurate characterizations of the subsurface and enabling us to better discover and describe hydrocarbon prospects, geothermal anomalies, seafloor hazards, aquifers, and much more.
10
Tselentis, G.-Akis, Nikolaos Martakis, Paraskevas Paraskevopoulos, Athanasios Lois, and Efthimios Sokos. "Strategy for automated analysis of passive microseismic data based on S-transform, Otsu’s thresholding, and higher order statistics." GEOPHYSICS 77, no. 6 (November 1, 2012): KS43—KS54. http://dx.doi.org/10.1190/geo2011-0301.1.
Full textAbstract:
Small-magnitude seismic events, either natural or induced microearthquakes, have increasingly been used in exploration seismology with applications ranging from hydrocarbon and geothermal reservoir exploration to high-resolution passive seismic tomography surveys. We developed an automated methodology for processing and analyzing continuously recorded, single-channel seismic data. This method comprised a chi-squared-based statistical test for microseismic event detection and denoising filtering in the S-transform domain based on the Otsu thresholding method. An automatic P-phase picker based on higher order statistics criteria was used. The method was used with data from a surface seismic station. The performance of the method was tested and evaluated on synthetic and real data from a microseismic network used in a high-resolution PST survey and revealed a high level of consistency.
11
Tsvankin, Ilya, James Gaiser, Vladimir Grechka, Mirko van der Baan, and Leon Thomsen. "Seismic anisotropy in exploration and reservoir characterization: An overview." GEOPHYSICS 75, no. 5 (September 2010): 75A15–75A29. http://dx.doi.org/10.1190/1.3481775.
Full textAbstract:
Recent advances in parameter estimation and seismic processing have allowed incorporation of anisotropic models into a wide range of seismic methods. In particular, vertical and tilted transverse isotropy are currently treated as an integral part of velocity fields employed in prestack depth migration algorithms, especially those based on the wave equation. We briefly review the state of the art in modeling, processing, and inversion of seismic data for anisotropic media. Topics include optimal parameterization, body-wave modeling methods, P-wave velocity analysis and imaging, processing in the [Formula: see text] domain, anisotropy estimation from vertical-seismic-profiling (VSP) surveys, moveout inversion of wide-azimuth data, amplitude-variation-with-offset (AVO) analysis, processing and applications of shear and mode-converted waves, and fracture characterization. When outlining future trends in anisotropy studies, we emphasize that continued progress in data-acquisition technology is likely to spur transition from transverse isotropy to lower anisotropic symmetries (e.g., orthorhombic). Further development of inversion and processing methods for such realistic anisotropic models should facilitate effective application of anisotropy parameters in lithology discrimination, fracture detection, and time-lapse seismology.
12
Treitel, Sven. "The MIT Geophysical Analysis Group (GAG): 1954 and beyond." GEOPHYSICS 70, no. 4 (July 2005): 31JA—35JA. http://dx.doi.org/10.1190/1.1993707.
Full textAbstract:
The MIT Geophysical Analysis Group (GAG) laid the groundwork for the so-called “digital revolution” in exploration seismology. Enders Robinson traces in this issue GAG's history from its earliest days till 1954; here, the story continues with GAG's subsequent evolution until its end in 1957. But that was just the beginning — during the 1960s and 1970s, the new digital technology spread throughout the oil and service industries worldwide, making it possible to develop progressively more sophisticated seismic processing and imaging algorithms that permanently changed the landscape of geophysical exploration.
13
Li, Zhenhua, and Mirko van der Baan. "Tutorial on rotational seismology and its applications in exploration geophysics." GEOPHYSICS 82, no. 5 (September 1, 2017): W17—W30. http://dx.doi.org/10.1190/geo2016-0497.1.
Full textAbstract:
Traditionally, seismological interpretations are based on the measurement of only translational motions, such as particle displacement, velocity, and/or acceleration, possibly combined with pressure changes; yet theory indicates that rotational motions should also be observed for a complete description of all ground motions. The recent and ongoing development of rotational sensors renders a full analysis of the translational and rotational ground motion possible. We have developed the basic mathematical theory related to rotational motion. And we also evaluated several instruments used to directly measure the rotational ground motion, which may be applicable for exploration geophysics. Finally, we made several applications of rotational motion in exploration geophysics, namely, (1) P- and S-wavefield separation, (2) wavefield reconstruction, (3) ground-roll removal, (4) microseismic event localization and reflection seismic migration by wavefield extrapolation, and (5) moment tensor inversion. The cited research shows that in particular, the information on the spatial gradient of the wavefield obtained by rotational sensors is beneficial for many purposes. This tutorial is meant to (1) enhance familiarity with the concept of rotational seismology, (2) lead to additional applications, and (3) fast track the continued development of rotational sensors for global and exploration geophysical use.
14
Zhu, Hejun, Yang Luo, Tarje Nissen-Meyer, Christina Morency, and Jeroen Tromp. "Elastic imaging and time-lapse migration based on adjoint methods." GEOPHYSICS 74, no. 6 (November 2009): WCA167—WCA177. http://dx.doi.org/10.1190/1.3261747.
Full textAbstract:
We have drawn connections between imaging in exploration seismology, adjoint methods, and emerging finite-frequency tomography. All of these techniques rely on spatial and temporal constructive interference between observed and simulated waveforms to map locations of structural anomalies. Modern numerical methods and computers have facilitated the accurate and efficient simulation of 3D acoustic, (an)elastic, and poroelastic wave propagation. Using a 2D cross section of the SEG/EAGE salt model, we have determined how such waveform simulations might be harnessed to improve onshore and offshore seismic imaging strategies and capabilities. We have found that the density sensitivity kernel in adjoint tomography is related closely to the imaging principle in exploration seismology, and that in elastic modeling the impedance kernel actually is a better diagnostic tool for reflector identification. The shear- and compressional-wave speed sensitivity kernels in adjoint tomography are related closely to finite-frequency banana-doughnut kernels, and these kernels are well suited for mapping larger-scale structure, i.e., for transmission tomography. These ideas have been substantiated by addressing problems in subsalt time-lapse migration.
15
Chebotareva, I. Ya. "Experimental capabilities of seismic emission tomography for solving the problems of searching and exploration of deep hydrocarbon accumulations." SOCAR Proceedings, SI2 (December 30, 2021): 26–35. http://dx.doi.org/10.5510/ogp2021si200540.
Full textAbstract:
The standard seismic prospecting has been designed to investigate thin layering at shallow depths. At depths more than 4 km the rocks are significantly compacted, change their properties and it is often impossible to trace clear horizons by reflected waves. In the crystalline basement and lower horizons of the sedimentary cover the block structure of rocks is clearly manifested. Taking this into account geological models should be developed and other predictive indicators should be used when searching for hydrocarbon accumulations. For the study of great depths more informative seismic methods are emission and transmission tomography which have been developed in detail in seismology. This article discusses prognostic indicators different from seismic prospecting and presents experimental results confirming the success of emission tomography in their detection using the example of field studies at developed hydrocarbon deposit and other geophysical objects. The range of working depths of research covers the entire crust of the Earth including the crust-mantle transition zone. Keywords: seismic emission; emission tomography; rocks; hydrocarbon deposits.
16
Barak, Ohad, Kerry Key, Steven Constable, and Shuki Ronen. "Recording active-seismic ground rotations using induction-coil magnetometers." GEOPHYSICS 83, no. 5 (September 1, 2018): P19—P42. http://dx.doi.org/10.1190/geo2017-0281.1.
Full textAbstract:
Most of the current rotational sensing technology is not geared toward the recording of seismic rotations’ amplitudes and frequencies. There are few instruments that are designed for rotational seismology, and the technology for building them is currently being developed. There are no mass industrial producers of seismic rotation sensors as there are for geophones, and only one current sensor model can be deployed on the ocean bottom. We reviewed some current rotational-seismic acquisition technologies, and developed a new method of recording rotations using an existing, robust and field-deployable technology that had seen extensive use in large exploration surveys: induction-coil magnetometers. We conducted an active seismic experiment, in which we found that magnetometers could be used to record seismic rotations. We converted the magnetometer data to rotation-rate data, and validated them by comparing the waveforms and amplitudes with rotation rates recorded by electrokinetic rotation sensors.
17
Tang, Zhi Yuan, Zan Dong Sun, and Yuan Yin Zhang. "Seismic Studies for Gas Hydrate Characterization in a Marine Case." Advanced Materials Research 468-471 (February 2012): 2759–63. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.2759.
Full textAbstract:
We combine an integrated study of gas hydrate reservoirs in a marine area from seismic data which collected for oil and gas exploration purpose. This study combines analyses of geology and seismology. First, geological analysis is made using data of material sources, structures and sediments to determine the hydrocarbon formation conditions of gas hydrate. Then seismic amplitude attributes analysis is conducted to predict the potential existence of four types of BSR in this area. Finally, pre-stacked inversion is conducted to predict the potential existence of hydrate and its free gas. Results show that gas hydrate is widely distribute in this area, and the distribution controlled by material source, reservoir space, and geothermal conditions.
18
Wapenaar, Kees, Joeri Brackenhoff, and Jan Thorbecke. "Green's theorem in seismic imaging across the scales." Solid Earth 10, no. 2 (April 11, 2019): 517–36. http://dx.doi.org/10.5194/se-10-517-2019.
Full textAbstract:
Abstract. The earthquake seismology and seismic exploration communities have developed a variety of seismic imaging methods for passive- and active-source data. Despite the seemingly different approaches and underlying principles, many of those methods are based in some way or another on Green's theorem. The aim of this paper is to discuss a variety of imaging methods in a systematic way, using a specific form of Green's theorem (the homogeneous Green's function representation) as a common starting point. The imaging methods we cover are time-reversal acoustics, seismic interferometry, back propagation, source–receiver redatuming and imaging by double focusing. We review classical approaches and discuss recent developments that fully account for multiple scattering, using the Marchenko method. We briefly indicate new applications for monitoring and forecasting of responses to induced seismic sources, which are discussed in detail in a companion paper.
19
Verpakhovska, A. O., G. D. Lesnoy, and A. I. Polunin. "A procedure of automatic evaluation of residual statistic adjustments for increasing information value of exploration seismology data." Geofizicheskiy Zhurnal 43, no. 2 (June 3, 2021): 14–27. http://dx.doi.org/10.24028/gzh.v43i2.230188.
Full textAbstract:
In present-day seismic exploration the quality of the observed wave field that guarantees obtaining the most exact and complete information on the structure of the studied area plays an important role. Therefore much attention is paid to elaboration of procedures for elimination of different noises and distortions present in the registered data. They include correction of statics or calculation and maintenance of static adjustments with taking into account the influence of small velocities zone (SVZ) and locality relief at each station of reception and explosion along the profile or observation area to the form of hodograph.
A procedure of automatic finding of residual statistic corrections based on usage of seismograms of equal distances and first wave arrivals without conducting their correlations that gives a possibility to exclude the effect of operator mistakes to the result has been considered. A theory has been proposed with algorithm consisting of putting in the observed wave fields, assortment of paths, finding temporal shifts by equidistant paths and computation of correcting adjustments for all the sources and receivers and the programming realization of finding the residual statistic corrections as a new interactive program corst3D, aimed at increasing the level of studies of structure of geological medium of different complexity by the data of both 2D and 3D seismic exploration. Effectiveness of the given procedure at the real data of seismic exploration for improvement of their quality and as a result for rising information value of their processing and interpretation has been shown together with colleagues of «GEOUNIT» company.
20
Pinzon-Rincon, Laura, François Lavoué, Aurélien Mordret, Pierre Boué, Florent Brenguier, Philippe Dales, Yehuda Ben-Zion, Frank Vernon, Christopher J. Bean, and Daniel Hollis. "Humming Trains in Seismology: An Opportune Source for Probing the Shallow Crust." Seismological Research Letters 92, no. 2A (January 20, 2021): 623–35. http://dx.doi.org/10.1785/0220200248.
Full textAbstract:
Abstract Seismologists are eagerly seeking new and preferably low-cost ways to map and track changes in the complex structure of the top few kilometers of the crust. By understanding it better, they can build on what is known regarding important, practical issues. These include telling us whether imminent earthquakes and volcanic eruptions are generating telltale underground signs of hazard, about mitigation of induced seismicity such as from deep injection of wastewater, how the Earth and its atmosphere couple, and where accessible natural resources are. Passive seismic imaging usually relies on blind correlations within extended recordings of Earth’s ceaseless “hum” or coda of well-mixed, small vibrations. In this article, we propose a complementary approach. It is seismic interferometry using opportune sources—specifically ones not stationary in time and moving in a well-understood configuration. Its interpretation relies on an accurate understanding of how these sources radiate seismic waves, precise timing, careful placement of pairs of listening stations, and seismic phase differentiation (surface and body waves). Massive freight trains were only recently recognized as such a persistent, powerful cultural (human activity-caused) seismic source. One train passage may generate a tremor with an energy output of a magnitude 1 earthquake and be detectable for up to 100 km from the track. We discuss the source mechanisms of train tremors and review the basic theory on sources. Finally, we present case studies of body- and surface-wave retrieval as an aid to mineral exploration in Canada and to monitoring of a southern California fault zone. We believe noise recovery from this new signal source, together with dense data acquisition technologies such as nodes or distributed acoustic sensing, will deeply transform our ability to monitor activity in the shallow crust at sharpened resolution in time and space.
21
Guo, Bowen, Yunsong Huang, Anders Røstad, and Gerard Schuster. "Far-field super-resolution imaging of resonant multiples." Science Advances 2, no. 5 (May 2016): e1501439. http://dx.doi.org/10.1126/sciadv.1501439.
Full textAbstract:
We demonstrate for the first time that seismic resonant multiples, usually considered as noise, can be used for super-resolution imaging in the far-field region of sources and receivers. Tests with both synthetic data and field data show that resonant multiples can image reflector boundaries with resolutions more than twice the classical resolution limit. Resolution increases with the order of the resonant multiples. This procedure has important applications in earthquake and exploration seismology, radar, sonar, LIDAR (light detection and ranging), and ultrasound imaging, where the multiples can be used to make high-resolution images.
22
Herrmann, Felix J., Deli Wang, Gilles Hennenfent, and Peyman P. Moghaddam. "Curvelet-based seismic data processing: A multiscale and nonlinear approach." GEOPHYSICS 73, no. 1 (January 2008): A1—A5. http://dx.doi.org/10.1190/1.2799517.
Full textAbstract:
Mitigating missing data, multiples, and erroneous migration amplitudes are key factors that determine image quality. Curvelets, little “plane waves,” complete with oscillations in one direction and smoothness in the other directions, sparsify a property we leverage explicitly with sparsity promotion. With this principle, we recover seismic data with high fidelity from a small subset (20%) of randomly selected traces. Similarly, sparsity leads to a natural decorrelation and hence to a robust curvelet-domain primary-multiple separation for North Sea data. Finally, sparsity helps to recover migration amplitudes from noisy data. With these examples, we show that exploiting the curvelet's ability to sparsify wavefrontlike features is powerful, and our results are a clear indication of the broad applicability of this transform to exploration seismology.
23
Robinson, Enders A. "Inversion of a seismic transmission response." GEOPHYSICS 66, no. 4 (July 2001): 1235–39. http://dx.doi.org/10.1190/1.1487070.
Full textAbstract:
Traveling waves are used not only in exploration geophysics but also in other disciplines faced with remote detection problems. A physical system may be described in terms of the input (the source), the medium, and the output (the received signal). The received signal can be made up of either transmitted waves or reflected waves. Two types of inverse problems can be considered, namely, the inverse source problem and the inverse medium problem. In the inverse source problem, the objective is to determine the source. In the inverse medium problem, the objective is to determine the medium. Thus, in terms of this general classification, four types of problems can be encountered, namely, an inverse source problem with transmitted waves, an inverse source problem with reflected waves, an inverse medium problem with transmitted waves, and an inverse medium problem with reflected waves. Let us look at nature. Twinkle, twinkle, little star. The transmission of starlight though the atmosphere makes the star twinkle. A better image of the star can be obtained by solving an inverse source problem using the transmitted starlight. In the typical inverse source problem, the source of energy is remote, the medium transmits the source signal, and the received data are the transmitted waves. Examples are classical earthquake seismology, radio transmission, and passive sonar. Shakespeare said; “For the eye sees not by itself, but by reflection.” Thus the miracle of eyesight solves an inverse medium problem that uses reflected waves. In the typical inverse medium problem, the source of energy is local and often man‐made, the medium reflects the source signal, and the received data are the reflected waves. Examples are reflection seismology, radar, and active sonar. Thus, the two principle types of inverse problems encountered in nature are the inverse source problem with transmitted waves and the inverse medium problem with reflected waves.
24
Pafeng, Josiane, Subhashis Mallick, and Hema Sharma. "Prestack waveform inversion of three-dimensional seismic data — An example from the Rock Springs Uplift, Wyoming, USA." GEOPHYSICS 82, no. 1 (January 1, 2017): B1—B12. http://dx.doi.org/10.1190/geo2016-0079.1.
Full textAbstract:
Applying seismic inversion to estimate subsurface elastic earth properties for reservoir characterization is a challenge in exploration seismology. In recent years, waveform-based seismic inversions have gained popularity, but due to high computational costs, their applications are limited, and amplitude-variation-with-offset/angle inversion is still the current state-of-the-art. We have developed a genetic-algorithm-based prestack seismic waveform inversion methodology. By parallelizing at multiple levels and assuming a locally 1D structure such that forward computation of wave equation synthetics is computationally efficient, this method is capable of inverting 3D prestack seismic data on parallel computers. Applying this inversion to a real prestack seismic data volume from the Rock Springs Uplift (RSU) located in Wyoming, USA, we determined that our method is capable of inverting the data in a reasonable runtime and producing much higher quality results than amplitude-variation-with-offset/angle inversion. Because the primary purpose for seismic data acquisition at the RSU was to characterize the subsurface for potential targets for carbon dioxide sequestration, we also identified and analyzed some potential primary and secondary storage formations and their associated sealing lithologies from our inversion results.
25
Boué, Pierre, Philippe Roux, Michel Campillo, and Benoit de Cacqueray. "Double beamforming processing in a seismic prospecting context." GEOPHYSICS 78, no. 3 (May 1, 2013): V101—V108. http://dx.doi.org/10.1190/geo2012-0364.1.
Full textAbstract:
The use of larger numbers of sensors is becoming more common at the large, continental scale for deep-structure imaging in seismology, and at a smaller scale with exploration geophysics objectives. Seismic arrays require array processing from which new types of observables contribute to a better understanding of the wave propagation complexity. From among these array processing techniques, this study focuses on a way to select and identify different phases between two source-receiver arrays based on the double beamforming (DBF) method. At the exploration geophysics scale, the goal is to identify and separate low-amplitude body waves from high-amplitude dispersive surface waves. A synthetic data set from a finite-difference time-domain simulation is first used to validate the array processing method. From directional information obtained with DBF, and due to the double-plane wave projection, it is demonstrated that surface and body waves can be extracted with a higher efficacy compared to classical beamforming even at short offset. A seismic prospecting data set in a laterally heterogeneous medium is then investigated. This data set is a high-resolution survey which provides a perfect control on source and receiver arrays geometry. The separation between the direct surface and body waves is observed after DBF and ray bending is discussed from the additional azimuthal information.
26
White, Benjamin, Balan Nair, and Alvin Bayliss. "Random rays and seismic amplitude anomalies." GEOPHYSICS 53, no. 7 (July 1988): 903–7. http://dx.doi.org/10.1190/1.1442527.
Full textAbstract:
We give an explanation of the phenomenon, sometimes observed in exploration seismology, of anomalously large amplitudes which seem inconsistent with the traveltime curves when the data are interpreted as resulting from reflections from smooth interfaces of piece‐wise homogeneous media. Monte Carlo simulations illustrate how this phenomenon can occur when the homogeneous media have small, smooth, random velocity fluctuations which vary on a length scale which is large compared with a wavelength but small compared with the propagation distance. Synthetic gathers of reflections from a single plane‐stratified layer with and without the random lateral inhomogeneities produce an amplitude anomaly which is related to the random occurrence of a caustic; limit theorems for stochastic differential equations provide a theory. Theoretical curves, giving the probability of first occurrence of this phenomenon along a ray as a function of propagation distance (for plane waves and for point and line sources in two and three dimensions) are qualitatively similar: they have an initial flat portion where amplitude anomalies are very unlikely, rise to a peak at the distance most likely for first occurrence, and decay exponentially to zero, thus predicting that the phenomenon will occur at some finite distance with probability one.
27
Geary, Andrew. "Honoring volunteers and sharing knowledge on the SEG Wiki." Leading Edge 38, no. 1 (January 2019): 69–72. http://dx.doi.org/10.1190/tle38010069.1.
Full textAbstract:
The SEG Wiki serves as a key foundation of the Society to engage the membership, the geoscience community, and the public in all-things applied geophysics. The wiki's main mission is to supply scientific material to the geoscience community and the public through online books, geophysical tutorials, geoscience articles, and biographies of geoscientists. SEG's two best-selling books are provided open and free of charge on the wiki. They include the Encyclopedic Dictionary of Applied Geophysics by Robert E. Sheriff and Seismic Data Analysis by Öz Yilmaz. A third book, Problems in Exploration Seismology and Their Solutions by L. P. Geldart and Robert E. Sheriff, will be added soon.
28
Wapenaar, Kees, Deyan Draganov, Roel Snieder, Xander Campman, and Arie Verdel. "Tutorial on seismic interferometry: Part 1 — Basic principles and applications." GEOPHYSICS 75, no. 5 (September 2010): 75A195–75A209. http://dx.doi.org/10.1190/1.3457445.
Full textAbstract:
Seismic interferometry involves the crosscorrelation of responses at different receivers to obtain the Green’s function between these receivers. For the simple situation of an impulsive plane wave propagating along the [Formula: see text]-axis, the crosscorrelation of the responses at two receivers along the [Formula: see text]-axis gives the Green’s function of the direct wave between these receivers. When the source function of the plane wave is a transient (as in exploration seismology) or a noise signal (as in passive seismology), then the crosscorrelation gives the Green’s function, convolved with the autocorrelation of the source function. Direct-wave interferometry also holds for 2D and 3D situations, assuming the receivers are surrounded by a uniform distribution of sources. In this case, the main contributions to the retrieved direct wave between the receivers come from sources in Fresnel zones around stationary points. The main application of direct-wave interferometry is theretrieval of seismic surface-wave responses from ambient noise and the subsequent tomographic determination of the surface-wave velocity distribution of the subsurface. Seismic interferometry is not restricted to retrieving direct waves between receivers. In a classic paper, Claerbout shows that the autocorrelation of the transmission response of a layered medium gives the plane-wave reflection response of that medium. This is essentially 1D reflected-wave interferometry. Similarly, the crosscorrelation of the transmission responses, observed at two receivers, of an arbitrary inhomogeneous medium gives the 3D reflection response of that medium. One of the main applications of reflected-wave interferometry is retrieving the seismic reflection response from ambient noise and imaging of the reflectors in the subsurface. A common aspect of direct- and reflected-wave interferometry is that virtual sources are created at positions where there are only receivers without requiring knowledge of the subsurface medium parameters or of the positions of the actual sources.
29
Borisov, Dmitry, Fuchun Gao, Paul Williamson, and Jeroen Tromp. "Application of 2D full-waveform inversion on exploration land data." GEOPHYSICS 85, no. 2 (January 9, 2020): R75—R86. http://dx.doi.org/10.1190/geo2019-0082.1.
Full textAbstract:
Estimating subsurface seismic properties is an important topic in civil engineering, oil and gas exploration, and global seismology. We have developed an application of 2D elastic waveform inversion with an active-source on-shore data set, as is typically acquired in exploration seismology on land. The maximum offset is limited to 12 km, and the lowest available frequency is 5 Hz. In such a context, surface waves are generally treated as noise and are removed as a part of data processing. In contrast to the conventional approach, our workflow starts by inverting surface waves to constrain shallow parts of the shear wavespeed model. To mitigate cycle skipping, frequency- and offset-continuation approaches are used. To accurately take into account free-surface effects (and irregular topography), a spectral-element-based wave propagation solver is used for forward modeling. To reduce amplitude influences, a normalized crosscorrelation (NC) objective function is used in conjunction with systematic updates of the source wavelet during the inversion process. As the inversion proceeds, body waves are gradually incorporated in the process. At the final stage, surface and body waves are inverted together using the entire offset range over the band between 5 and 15 Hz. The inverted models include high-resolution features in the first 500 m of compressional and shear wavespeeds, with some model updates down to 4.0 km in the first parameter. The inversion results confirmed by well-log information, indicate a better fit of compressional to shear wavespeeds ratios compared with the initial model. The final data fit is also noticeably improved compared to the initial one. Although our results confirm previous studies demonstrating that an NC norm combined with a source time function correction can partly stabilize purely elastic inversions of viscoelastic data, we believe that including an attenuation depth model in the forward simulation gives better results.
30
Fernando, Benjamin, Natalia Wójcicka, Ross Maguire, Simon C. Stähler, Alexander E. Stott, Savas Ceylan, Constantinos Charalambous, et al. "Seismic constraints from a Mars impact experiment using InSight and Perseverance." Nature Astronomy 6, no. 1 (October 28, 2021): 59–64. http://dx.doi.org/10.1038/s41550-021-01502-0.
Full textAbstract:
AbstractNASA’s InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission has operated a sophisticated suite of seismology and geophysics instruments on the surface of Mars since its arrival in 2018. On 18 February 2021, we attempted to detect the seismic and acoustic waves produced by the entry, descent and landing of the Perseverance rover using the sensors onboard the InSight lander. Similar observations have been made on Earth using data from both crewed1,2 and uncrewed3,4 spacecraft, and on the Moon during the Apollo era5, but never before on Mars or another planet. This was the only seismic event to occur on Mars since InSight began operations that had an a priori known and independently constrained timing and location. It therefore had the potential to be used as a calibration for other marsquakes recorded by InSight. Here we report that no signal from Perseverance’s entry, descent and landing is identifiable in the InSight data. Nonetheless, measurements made during the landing window enable us to place constraints on the distance–amplitude relationships used to predict the amplitude of seismic waves produced by planetary impacts and place in situ constraints on Martian impact seismic efficiency (the fraction of the impactor kinetic energy converted into seismic energy).
31
Yang, Zhen, and Jun Lu. "Second-Order Approximation of the Seismic Reflection Coefficient in Thin Interbeds." Energies 13, no. 6 (March 20, 2020): 1465. http://dx.doi.org/10.3390/en13061465.
Full textAbstract:
As most of the lithostratigraphic reservoirs in China are thin interbeds, the study of seismic responses in thin interbeds is an integral part of lithologic reservoir exploration. However, at present, the research on seismic reflection coefficients of thin interbeds in exploration seismology is still weak, which leads to the lack of theoretical basis for the subsequent interpretation of amplitude variation with offset (AVO) related to thin interbed. To solve this problem, in this paper, we proposed second-order approximate equations of the seismic reflection coefficients in thin-bed and thin-interbed layers. Under the assumption of a small impedance contrast in layered media, we made a second-order approximation with a more evident physical meaning to the reflection coefficient calculation method proposed by Kennett. Then, based on the test of the single thin-layer theoretical model, it was confirmed that the second-order approximation equation of the PP-wave (reflected compressional wave) is accurate at incident angles less than 30°, and that of the PS-wave (converted shear wave) is accurate at wider incident angles. Finally, based on the single-thin-bed equations, the approximate equations of seismic reflection coefficients in thin interbeds were established, the validity of which was verified by the theoretical model. Our equations will be applicable to the calculation of PP- and PS-wave reflection coefficients in thin interbeds where internal multiples are difficult to suppress and transmission loss is hard to accurately compensate. This lays a theoretical foundation for improving the seismic prediction accuracy of lithologic reservoirs.
32
Муратов, М. В., Д. И. Петров, В. В. Рязанов, and В. А. Бирюков. "Machine Learning Applications to Solving Inverse Problems in Fractured Layer Seismic Surveys." Успехи кибернетики / Russian Journal of Cybernetics, no. 1 (March 25, 2022): 8–13. http://dx.doi.org/10.51790/2712-9942-2022-3-1-1.
Full textAbstract:
В данной работе решаются обратные задачи сейсморазведки в средах с однородно ориентированными трещиноватыми включениями с применением сверточных нейронных сетей. Выбор данного вида нейронных сетей определен большой размерностью массива данных. Построение обучающей выборки из прямых задач для обучения нейронной сети осуществляется с помощью математического моделирования. Для численного решения прямых задач был взят сеточно-характеристический метод на неструктурированных сетках. Выбор численного метода обусловлен волновой природой изучаемых динамических процессов, которая хорошо учитывается сеточно-характеристическим методом. Данный подход хорошо зарекомендовал себя при построении корректных вычислительных алгоритмов для граничных и контактных условий, в частности, для задания дискретного массива трещин. Целью работы является определение характеристик одиночной трещины и пластов таких трещин. Была успешно решена обратная задача сейсморазведки для пласта трещин с шестью неизвестными параметрами: высота и угол наклона трещин, плотность расположения трещин, горизонтальная протяженность пласта и его пространственное положение в 2D. В процессе обучения нейронной сети и распознавания элементов валидационной выборки, помимо данных о скоростях колебаний в массиве сейсмических данных, на вход сети также подавался их частотный спектр. In this paper, we solve inverse problems of exploration seismology in rocks with uniformly oriented fractured inclusions using convolutional neural networks. This type of neural network was chosen due to the large dataset. We used simulation to build a neural network training sample from the direct problem results. For the numerical solution of direct problems, a grid-characteristic method was applied to unstructured meshes. This numerical method was used since the studied dynamic processes are of wave nature, which is very suitable for the grid-characteristic method. This approach is proven in building correct computational algorithms for boundary and interface conditions, in particular, for defining discrete fracture arrays. The problem statement is to determine the characteristics of a single fracture and layers of such fractures. The inverse exploration seismology problem for a fractured layer with six unknown parameters was successfully solved. These parameters are the height and angle of inclination of the fractures, the density of the fractures, the horizontal extent of the formation, and its 2D position. The vibration velocities in the seismic data array and the frequency spectra were inputs for the neural network training and validation sample recognition.
33
Yan, Yuefeng, Chengyu Sun, Tengfei Lin, Jiao Wang, Jidong Yang, and Dunshi Wu. "Surface-Wave Simulation for the Continuously Moving Seismic Sources." Seismological Research Letters 92, no. 4 (March 24, 2021): 2429–40. http://dx.doi.org/10.1785/0220200236.
Full textAbstract:
Abstract In exploration and earthquake seismology, most sources used in subsurface structure imaging and rock property estimation are fixed in certain positions. Continuously moving seismic sources, such as vehicles and the metro, are one kind of important passive sources in ambient noise research. Commonly, seismic data acquisition and processing for moving sources are based on the assumption of simple point passive sources, and the dispersion curve inversion is applied to constrain near-surface velocity. This workflow neglects the Doppler effects. Considering the continuously moving properties of the sources, we first derive the analytical solution for the Rayleigh waves excited by heavy vehicles and then analyze their Doppler effects and dispersion curves. We observe that the moving source data have the Doppler effect when compared with the changes in the frequency of the source intensity, but this effect does not affect the frequency dispersion of Rayleigh waves. The dispersion curves computed for moving source records are consistent with the analytical dispersion solutions, which provide a theoretical foundation for velocity estimation using moving source data.
34
Levin, Ilya, Andrei Ponomarenko, Vyacheslav Polovkov, Dmitry Popov, and Vladimir Troyan. "On the method of surface-wave tomography and perspectives for its application in engineering seismic exploration." Vestnik of Saint Petersburg University. Earth Sciences 67, no. 2 (2022): 202–26. http://dx.doi.org/10.21638/spbu07.2022.201.
Full textAbstract:
The upper part of the seismic section is studied using refracted waves, as well as surface waves using the MASW method during engineering seismic surveys. This work is devoted to consideration of a relatively new near-surface approach, which is actively used in seismology for studying the upper mantle and deep part of the earth's crust, the method of surface wave tomography. This method is of great practical interest, since it allows to obtain 3D subsurface models and conduct remote researches; also it potentially has better spatial resolution than the widely used MASW method. Within the framework of this work, tests of the developed algorithm for surface-wave tomography using direct rays were carried out on modeled data. The performance of the algorithm was assessed and the resolution of the method was estimated. Also the optimal observation schemes were considered as well as the influence of the regularization parameter value on the inversion result. Basing on the results of the current study, it can be concluded that the method of surface-wave tomography and its realization via the developed algorithm can be effectively used to solve engineering-geological problems.
35
Ortiz-Aguilar, Stephany, Jonas D. De Basabe, Mario Gonzalez-Escobar, and Vanesa Magar. "Theoretical signature of a cavern created by an underground nuclear explosion in 2-D exploration seismic data." Geophysical Journal International 221, no. 3 (February 21, 2020): 1789–801. http://dx.doi.org/10.1093/gji/ggaa074.
Full textAbstract:
SUMMARY The proliferation of nuclear tests is a problem that threatens the safety and health of everybody. In order to tackle this problem, the UN is promoting the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which includes protocols for monitoring and On-Site Inspections (OSI). The purpose of OSI is to verify if a nuclear test has been carried out by identifying with a geophysical technique the presence of a cavern, hole or some device that indicates the violation of the treaty. In this context, it is desirable to be able to use exploration-seismology techniques to detect caverns created by an underground nuclear explosion. However, there is scarce information about the seismic signature of this type of cavern. We present the results of elastic wave propagation simulations, in the time domain, with a cavern created by an underground nuclear explosion. The wave equation is solved using the spectral element method with 4th order basis functions and quadrilateral elements. We show the results for models with cavities and caverns corresponding to explosions of 1, 20 and 100 kilotons, and obtain seismic traces in which we can observe the effect of the structures. We conclude that caverns created by nuclear explosions can be detected using seismic data and distinguished from caves because they behave like two concentric diffractor bodies, as opposed to caves-like diffractors.
36
Ramírez, Adriana Citlali, and Arthur B. Weglein. "Green’s theorem as a comprehensive framework for data reconstruction, regularization, wavefield separation, seismic interferometry, and wavelet estimation: A tutorial." GEOPHYSICS 74, no. 6 (November 2009): W35—W62. http://dx.doi.org/10.1190/1.3237118.
Full textAbstract:
Almost every link in the chain of exploration seismology methods used to process recorded data has been affected by Green’s theorem. Among the seismic processes that can be related to, and/or have benefited from, Green’s theorem are wavelet estimation, multiple elimination, regularization, redatuming, imaging, deghosting, and interferometry. This tutorial on various seismic exploration methods derived from Green’s theorem emphasizes seismic data reconstruction (including regularization and redatuming) and its relationship to interferometry as well as to wavelet estimation and wavefield separation. The last decade has witnessed ever-increasing attention within the energy industry and its concomitant representation in the published literature to methods dealing with wavefield reconstruction through in-terferometry or virtual-source techniques. The attention has re- newed interest in Green’s theorem because all different ap-proaches to interferometry can be derived from it. This tutorial provides a derivation and explication of the limitations of interferometric techniques (when interferometry is used to process measured data from marine surface seismic experiments with controlled sources) as approximations to Green’s theorem. This tutorial provides a definite statement of the comprehensive framework given by Green’s theorem to wavefield reconstruction and shows how different techniques are directly understood as specific mathematical forms and/or approximations to the theorem. The use of approximations can have shortcomings and create artifacts. These artifacts and errors are also analyzed and explained. All methods discussed in this tutorial recognize their foundation on Green’s theorem and have a secure mathematical-physics cornerstone to recognize the assumptions behind distinct approximate solutions and to guide the search for more accurate, effective techniques.
37
Louboutin, Mathias, Michael Lange, Fabio Luporini, Navjot Kukreja, Philipp A. Witte, Felix J. Herrmann, Paulius Velesko, and Gerard J. Gorman. "Devito (v3.1.0): an embedded domain-specific language for finite differences and geophysical exploration." Geoscientific Model Development 12, no. 3 (March 27, 2019): 1165–87. http://dx.doi.org/10.5194/gmd-12-1165-2019.
Full textAbstract:
Abstract. We introduce Devito, a new domain-specific language for implementing high-performance finite-difference partial differential equation solvers. The motivating application is exploration seismology for which methods such as full-waveform inversion and reverse-time migration are used to invert terabytes of seismic data to create images of the Earth's subsurface. Even using modern supercomputers, it can take weeks to process a single seismic survey and create a useful subsurface image. The computational cost is dominated by the numerical solution of wave equations and their corresponding adjoints. Therefore, a great deal of effort is invested in aggressively optimizing the performance of these wave-equation propagators for different computer architectures. Additionally, the actual set of partial differential equations being solved and their numerical discretization is under constant innovation as increasingly realistic representations of the physics are developed, further ratcheting up the cost of practical solvers. By embedding a domain-specific language within Python and making heavy use of SymPy, a symbolic mathematics library, we make it possible to develop finite-difference simulators quickly using a syntax that strongly resembles the mathematics. The Devito compiler reads this code and applies a wide range of analysis to generate highly optimized and parallel code. This approach can reduce the development time of a verified and optimized solver from months to days.
38
Siahkoohi, Ali, Mathias Louboutin, and Felix J. Herrmann. "The importance of transfer learning in seismic modeling and imaging." GEOPHYSICS 84, no. 6 (November 1, 2019): A47—A52. http://dx.doi.org/10.1190/geo2019-0056.1.
Full textAbstract:
Accurate forward modeling is essential for solving inverse problems in exploration seismology. Unfortunately, it is often not possible to afford being physically or numerically accurate. To overcome this conundrum, we make use of raw and processed data from nearby surveys. We have used these data, consisting of shot records or velocity models, to pretrain a neural network to correct for the effects of, for instance, the free surface or numerical dispersion, both of which can be considered as proxies for incomplete or inaccurate physics. Given this pretrained neural network, we apply transfer learning to fine-tune this pretrained neural network so it performs well on its task of mapping low-cost, but low-fidelity, solutions to high-fidelity solutions for the current survey. As long as we can limit ourselves during fine-tuning to using only a small fraction of high-fidelity data, we gain processing the current survey while using information from nearby surveys. We examined this principle by removing surface-related multiples and ghosts from shot records and the effects of numerical dispersion from migrated images and wave simulations.
39
Belyaeva, I. Yu, L. A. Ostrovsky, and V. Yu Zaitsev. "Microstructure induced nonlinearity of unconsolidated rocks as related to seismic diagnostic problems." Nonlinear Processes in Geophysics 4, no. 1 (March 31, 1997): 1–10. http://dx.doi.org/10.5194/npg-4-1-1997.
Full textAbstract:
Abstract. Manifestations of the so-called structure induced nonlinearity are considered for the case of a granular medium, the latter being a generally accepted model of nonconsolidated rocks in seismics. The consideration is carried out using the medium model in the form of the "ideal" random packing of spherical elastic granules in which the interparticle space can be filled with a fluid. A physical equation of such a medium is derived; the dependencies of nonlinear parameters on the grain material elastic moduli, the fluid compressibility and the initial medium strain are analyzed. The influence of defects in nonideal grain packings (that is, the presence of a fraction of unloaded intergranular contacts) upon the nonlinear properties of the medium is investigated. It is shown that the packing nonideality has the stronger effect on higher-order nonlinear properties. It is demonstrated that the nonlinear parameters may be used in exploration seismology as a much more sensitive and informative characteristic compared with conventionally used linear moduli.
40
Liu, Guofeng, Xiaohong Meng, Jianhui Ni, Zhaoxi Chen, and Da Zhang. "Evaluation of the 2D reflection seismic method toward the exploration of thrust-controlled mineral deposits in southwestern Fujian Province, China." GEOPHYSICS 83, no. 4 (July 1, 2018): B209—B220. http://dx.doi.org/10.1190/geo2017-0289.1.
Full textAbstract:
The southwestern region of the Fujian Province is one of the major ore districts in China. The current model states that mineral deposition is highly controlled by thrust structure, which means that there may be concealed deposits located deep within overlapping thrust areas. Reflection seismology, which has great depth penetration and higher resolution than other geophysical methods, has great potential to delineate complex structures and give some clues to mineralization. In 2015, an experimental 2D reflection seismic survey called “Fujian 2D” was conducted in this region. Data were acquired along a 13.8 km length, with a source interval of 60 m, and 691 identical receivers with an equal spacing of 20 m were used to record data for each source. Due to topographical restrictions caused by the source environment, the mass or position of some shots was changed. Despite the restrictions, the average fold number reached 64 for a 10 km distance along the middle of the survey line. During the data processing procedure, conventional technologies involving static correction, noise elimination, deconvolution, and iterative velocity analyses were applied. After the prestack time migration failed to obtain a high-quality imaging result, rugged prestack depth migration (PSDM) was introduced that resulted in a better quality image of the subsurface structure and which included near-surface parts of the thrusts. In addition, P- and S-wave velocities and density data were determined from two borehole cores. Forward modeling and imaging found that the Permian marble hosting the mineral deposits has lower velocity than the surrounding rocks, where contacts give rise to strong reflections. The final rugged PSDM also clearly delineated the thrust bodies and magma intrusion zones. Combining this forward modeling with the known geology of the investigated site, the Fujian 2D reflection seismic experiment demonstrates great potential for unveiling the main elements controlling mineral deposition, such as tectonic structure, stratigraphic contacts, and lithology. Our experimental results demonstrate that reflection seismology has a wide range of applications for future mineral exploration at greater depths.
41
Trinks, Immo, and Alois Hinterleitner. "Beyond Amplitudes: Multi-Trace Coherence Analysis for Ground-Penetrating Radar Data Imaging." Remote Sensing 12, no. 10 (May 16, 2020): 1583. http://dx.doi.org/10.3390/rs12101583.
Full textAbstract:
Under suitable conditions, ground-penetrating radar (GPR) measurements harbour great potential for the non-invasive mapping and three-dimensional investigation of buried archaeological remains. Current GPR data visualisations almost exclusively focus on the imaging of GPR reflection amplitudes. Ideally, the resulting amplitude maps show subsurface structures of archaeological interest in plan view. However, there exist situations in which, despite the presence of buried archaeological remains, hardly any corresponding anomalies can be observed in the GPR time- or depth-slice amplitude images. Following the promising examples set by seismic attribute analysis in the field of exploration seismology, it should be possible to exploit other attributes than merely amplitude values for the enhanced imaging of subsurface structures expressed in GPR data. Coherence is the seismic attribute that is a measure for the discontinuity between adjacent traces in post-stack seismic data volumes. Seismic coherence analysis is directly transferable to common high-resolution 3D GPR data sets. We demonstrate, how under the right circumstances, trace discontinuity analysis can substantially enhance the imaging of structural information contained in GPR data. In certain cases, considerably improved data visualisations are achievable, facilitating subsequent data interpretation. We present GPR trace coherence imaging examples taken from extensive, high-resolution archaeological prospection GPR data sets.
42
Nishitsuji, Yohei, Shohei Minato, Boris Boullenger, Martín Gomez, Kees Wapenaar, and Deyan Draganov. "Crustal-scale reflection imaging and interpretation by passive seismic interferometry using local earthquakes." Interpretation 4, no. 3 (August 1, 2016): SJ29—SJ53. http://dx.doi.org/10.1190/int-2015-0226.1.
Full textAbstract:
We have developed an application of passive seismic interferometry (SI) using P-wave coda of local earthquakes for the purpose of crustal-scale reflection imaging. We processed the reflection gathers retrieved from SI following a standard seismic processing in exploration seismology. We applied SI to the P-wave coda using crosscorrelation, crosscoherence, and multidimensional deconvolution (MDD) approaches for data recorded in the Malargüe region, Argentina. Comparing the results from the three approaches, we found that MDD based on the truncated singular-value decomposition scheme gave us substantially better structural imaging. Although our results provided higher resolution images of the subsurface, they showed less clear images for the Moho in comparison with previous seismic images in the region obtained by the receiver function and global-phase SI. Above the Moho, we interpreted a deep thrust fault and the possible melting zones, which were previously indicated by active-seismic and magnetotelluric methods in this region, respectively. The method we developed could be an alternative option not only for crustal-scale imaging, e.g., in enhanced geothermal systems, but also for lithospheric-scale as well as basin-scale imaging, depending on the availability of local earthquakes and the frequency bandwidth of their P-wave coda.
43
Franssens, G. R., P. E. Lagasse, and I. M. Mason. "Study of the leaking channel modes of in‐seam exploration seismology by means of synthetic seismograms." GEOPHYSICS 50, no. 3 (March 1985): 414–24. http://dx.doi.org/10.1190/1.1441920.
Full textAbstract:
If the dispersion characteristics of coal‐seam channel guides do not extend smoothly at frequencies below cut‐off, the number of parameters required to process inseam seismic data increases. Unwanted modes become more difficult to suppress, the arriving pulses from targets become more difficult both to identify and to pulse compress. The connection between leaking and normal channel mode dispersion is established here by first synthesizing and then analyzing theoretical in‐seam seismograms. Calculation of synthetic seismograms is based on numerical evaluation of the spatial Fourier integral for elastic displacements in the complex wavenumber plane. Theoretical seismograms are presented for three‐layered models. Phase velocity characteristics are recovered from these signals and compared with those obtained from the zero loci of the period equation in the complex wavenumber plane. Under cut‐off the former method yields smooth extensions of the normal mode dispersion characteristics, in contrast to the velocity curves obtained from the period equation only. It is found that the dispersion characteristics obtained from analyzing the seismograms can be used to recompress the dispersed arrivals.
44
Cano, Eduardo Valero, Jubran Akram, and Daniel B. Peter. "Automatic seismic phase picking based on unsupervised machine-learning classification and content information analysis." GEOPHYSICS 86, no. 4 (June 30, 2021): V299—V315. http://dx.doi.org/10.1190/geo2020-0308.1.
Full textAbstract:
Accurate identification and picking of P- and S-wave arrivals is important in earthquake and exploration seismology. Often, existing algorithms are lacking in automation, multiphase classification and picking, as well as performance accuracy. We have developed a new fully automated four-step workflow for efficient classification and picking of P- and S-wave arrival times on microseismic data sets. First, time intervals with possible arrivals on waveform recordings are identified using the fuzzy c-means clustering algorithm. Second, these intervals are classified as corresponding to P-, S-, or unidentified waves using the polarization attributes of the waveforms contained within. Third, the P-, S-, and unidentified-waves arrival times are picked using the Akaike information criterion picker on the corresponding intervals. Fourth, unidentified waves are classified as P or S based on the arrivals moveouts. The application of the workflow on synthetic and real microseismic data sets indicates that it yields accurate arrival picks for high and low signal-to-noise ratio waveforms.
45
Muratov, Maxim V., Polina V. Stognii, Igor B. Petrov, Alexey A. Anisimov, and Nazim A. Karaev. "The study of dynamical processes in problems of mesofracture layers exploration seismology by methods of mathematical and physical simulation." Radioelectronics. Nanosystems. Information Technologies. 13, no. 1 (March 27, 2021): 71–78. http://dx.doi.org/10.17725/rensit.2021.13.071.
Full textAbstract:
The article is devoted to the study of the propagation of elastic waves in a fractured seismic medium by methods of mathematical modeling. The results obtained during it are compared with the results of physical modeling on similar models. For mathematical modeling, the grid-characteristic method with hybrid schemes of 1-3 orders with approximation on structural rectangular grids is used. The ability to specify inhomogeneities (fractures) of various complex shapes and spatial orientations has been implemented. The description of the developed mathematical models of fractures, which can be used for the numerical solution of exploration seismology problems, is given. The developed models are based on the concept of an infinitely thin fracture, the size of the opening of which does not affect the wave processes in the fracture area. In this model, fractures are represented by boundaries and contact boundaries with different conditions on their surfaces. This approach significantly reduces the need for computational resources by eliminating the need to define a mesh inside the fracture. On the other hand, it allows you to specify in detail the shape of fractures in the integration domain, therefore, using the considered approach, one can observe qualitatively new effects, such as the formation of diffracted waves and a multiphase wavefront due to multiple reflections between the surfaces, which are inaccessible for observation when using effective fracture models actively used in computational seismic. The obtained results of mathematical modeling were verified by physical modeling methods, and a good agreement was obtained.
46
Zhu, Tieyuan. "Numerical simulation of seismic wave propagation in viscoelastic-anisotropic media using frequency-independent Q wave equation." GEOPHYSICS 82, no. 4 (July 1, 2017): WA1—WA10. http://dx.doi.org/10.1190/geo2016-0635.1.
Full textAbstract:
Seismic anisotropy is the fundamental phenomenon of wave propagation in the earth’s interior. Numerical modeling of wave behavior is critical for exploration and global seismology studies. The full elastic (anisotropy) wave equation is often used to model the complexity of velocity anisotropy, but it ignores attenuation anisotropy. I have presented a time-domain displacement-stress formulation of the anisotropic-viscoelastic wave equation, which holds for arbitrarily anisotropic velocity and attenuation [Formula: see text]. The frequency-independent [Formula: see text] model is considered in the seismic frequency band; thus, anisotropic attenuation is mathematically expressed by way of fractional time derivatives, which are solved using the truncated Grünwald-Letnikov approximation. I evaluate the accuracy of numerical solutions in a homogeneous transversely isotropic (TI) medium by comparing with theoretical [Formula: see text] and [Formula: see text] values calculated from the Christoffel equation. Numerical modeling results show that the anisotropic attenuation is angle dependent and significantly different from the isotropic attenuation. In synthetic examples, I have proved its generality and feasibility by modeling wave propagation in a 2D TI inhomogeneous medium and a 3D orthorhombic inhomogeneous medium.
47
Li, Yiran, and Alex Nikulin. "Basin-scale subsurface characterization using single-station teleseismic receiver function analysis." Leading Edge 41, no. 10 (October 2022): 700–708. http://dx.doi.org/10.1190/tle41100700.1.
Full textAbstract:
Teleseismic receiver function (RF) analysis traditionally has targeted deep earth structures in the context of observational seismology, allowing the detection of converted seismic phases originating from major boundaries of impedance. Recent efforts to adapt this passive-source seismic imaging technique to basin-scale subsurface characterization have retrieved primary basin geometries and key stratigraphic boundaries by relying on densely deployed broadband seismometer networks. While accurate interpretation of RF time series on Earth benefitted from complementary subsurface constraints (e.g., core and well logs), lack of such resources and instrumental limitations must be considered in the context of planetary geophysics, where passive-source imaging may emerge as a key frontier exploration technique. Thus, it is important to establish an analysis framework in which observed RF signals are interpreted by relying on first-order suppositions about the physical properties of the underlying subsurface. In this work, we seek to simulate this approach in single-station scenarios and qualitatively examine the baseline information inferable from the RF time series. Our results suggest that signals observed in the sedimentary interval can be reasonably attributed to major impedance changes expected from the generalized lithostratigraphy of the local subsurface, including the transition to the underlying crust. We also find patterns of anisotropy-related directional variations in high-frequency signals as well as unique frequency-dependent responses likely associated with the depth and vertical dimension of converting boundaries. Together, these seismic observables enable inference of various geologic attributes within the underlying sedimentary unit, proving it to be a critical tool in future efforts of planetary exploration.
48
Louie, J. N., and J. E. Vidale. "Array analysis of reflector heterogeneity." GEOPHYSICS 56, no. 4 (April 1991): 565–71. http://dx.doi.org/10.1190/1.1443074.
Full textAbstract:
In deep crustal reflection study, as in conventional exploration seismology, it is important to determine the geometry of the physical contrasts between rocks that cause reflections, to make reliable geologic interpretations. Fundamentally different reflecting structures produce similar signatures in stacked seismic sections. We have developed a method that uses prestack records to differentiate lateral structural variations from lateral reflectivity variations and laterally homogeneous structures. Full‐wave acoustic multioffset synthetics of canonical 2-D reflector configurations, analyzed by statistically enhanced slant‐stack processes, show that lateral heterogeneity such as a wavy reflector can be identified from changes in slowness across a receiver array as a function of time. Application of these methods to deep crustal reflections, recorded in the Mojave Desert of southern California, identifies laterally heterogeneous midcrustal structures and is consistent with a laterally homogeneous Moho.
49
Theune, Ulrich, Ingrid Østgård Jensås, and Jo Eidsvik. "Analysis of prior models for a blocky inversion of seismic AVA data." GEOPHYSICS 75, no. 3 (May 2010): C25—C35. http://dx.doi.org/10.1190/1.3427538.
Full textAbstract:
Resolving thinner layers and focusing layer boundaries better in inverted seismic sections are important challenges in exploration and production seismology to better identify a potential drilling target. Many seismic inversion methods are based on a least-squares optimization approach that can intrinsically lead to unfocused transitions between adjacent layers. A Bayesian seismic amplitude variation with angle (AVA) inversion algorithm forms sharper boundaries between layers when enforcing sparseness in the vertical gradients of the inversion results. The underlying principle is similar to high-resolution processing algorithms and has been adapted from digital-image-sharpening algorithms. We have investigated the Cauchy and Laplace statistical distributions for their potential to improve contrasts betweenlayers. An inversion algorithm is derived statistically from Bayes’ theorem and results in a nonlinear problem that requires an iterative solution approach. Bayesian inversions require knowledge of certain statistical properties of the model we want to invert for. The blocky inversion method requires an additional parameter besides the usual properties for a multivariate covariance matrix, which we can estimate from borehole data. Tests on synthetic and field data show that the blocky inversion algorithm can detect and enhance layer boundaries in seismic inversions by effectively suppressing side lobes. The analysis of the synthetic data suggests that the Laplace constraint performs more reliably, whereas the Cauchy constraint may not find the optimum solution by converging to a local minimum of the cost function and thereby introducing some numerical artifacts.
50
Ma, Rupeng, Jing Ba, José M. Carcione, and Maxim Lebedev. "P-wave scattering by randomly distributed aligned cracks in fractal media." Geophysical Journal International 229, no. 2 (October 30, 2021): 900–914. http://dx.doi.org/10.1093/gji/ggab450.
Full textAbstract:
SUMMARY Seismic wave scattering dispersion and attenuation can be significant in cracked reservoirs. Many scattering models have been proposed, and the fractal (self-similar) features of the medium need to be further incorporated and analysed. We solve the P-wave scattering caused by fluid-saturated aligned cracks of finite thickness embedded in fractal media. The model is based on crack displacement discontinuities by using the Foldy approximation and representation theorem. The frequency dependence of velocity and attenuation are analysed as a function of the incidence angle and the crack and fluid properties. The results show that the crack density, thickness and radius can have a significant influence on the wave properties, as well as the fluid bulk modulus and saturation. The model requires three parameters to describe self-similar cracked media, and can be relevant in seismology, oil exploration and non-destructive testing of materials.