ISOEDIT : a program for interactive editing of seismic reflection velocity models computer file, Part A

1989 ◽  
Author(s):  
Frederick N. Zihlman
Keyword(s):  
Seismic Reflection ◽  
Computer File ◽  
Velocity Models ◽  
Interactive Editing

A multioffset, three‐component VSP study in the Sudbury Basin

Geophysics ◽  
1995 ◽  
Vol 60 (2) ◽  
pp. 341-353 ◽  
Author(s):  
Xiao‐Gui Miao ◽  
Wooil M. Moon ◽  
B. Milkereit
Keyword(s):  
Data Processing ◽  
Seismic Reflection ◽  
Velocity Structure ◽  
Least Square ◽  
Seismic Reflection Data ◽  
S Waves ◽  
Velocity Models ◽  
Reflection Data ◽  
Wavefield Separation ◽  
Vsp Data

A multioffset, three‐component vertical seismic profiling (VSP) experiment was carried out in the Sudbury Basin, Ontario, as a part of the LITHOPROBE Sudbury Transect. The main objectives were determination of the shallow velocity structure in the middle of the Sudbury Basin, development of an effective VSP data processing flow, correlation of the VSP survey results with the surface seismic reflection data, and demonstration of the usefulness of the VSP method in a crystalline rock environment. The VSP data processing steps included rotation of the horizontal component data, traveltime inversion for velocity analysis, Radon transform for wavefield separation, and preliminary analysis of shear‐wave data. After wavefield separation, the flattened upgoing wavefields for both P‐waves and S‐waves display consistent reflection events from three depth levels. The VSP-CDP transformed section and corridor stacked section correlate well with the high‐resolution surface reflection data. In addition to obtaining realistic velocity models for both P‐ and S‐waves through least‐square inversion and synthetic seismic modeling for the Chelmsford area, the VSP experiment provided an independent estimation for the reflector dip using three component hodogram analysis, which indicates that the dip of the contact between the Chelmsford and Onwatin formations, at an approximate depth of 380 m in the Chelmsford borehole, is approximately 10.5° southeast. This study demonstrates that multioffset, three‐component VSP experiments can provide important constraints and auxiliary information for shallow crustal seismic studies in crystalline terrain. Thus, the VSP technique bridges the gap between the surface seismic‐reflection technique and well‐log surveys.

Integrating high‐resolution refraction data into near‐surface seismic reflection data processing and interpretation

Geophysics ◽  
1998 ◽  
Vol 63 (4) ◽  
pp. 1339-1347 ◽  
Author(s):  
Kate C. Miller ◽  
Steven H. Harder ◽  
Donald C. Adams ◽  
Terry O’Donnell
Keyword(s):  
Seismic Reflection ◽  
Velocity Model ◽  
Surface Velocity ◽  
Seismic Profiles ◽  
Seismic Reflection Data ◽  
Near Surface ◽  
Interval Velocity ◽  
Velocity Models ◽  
Reflection Data ◽  
Seismic Reflection Profiles

Shallow seismic reflection surveys commonly suffer from poor data quality in the upper 100 to 150 ms of the stacked seismic record because of shot‐associated noise, surface waves, and direct arrivals that obscure the reflected energy. Nevertheless, insight into lateral changes in shallow structure and stratigraphy can still be obtained from these data by using first‐arrival picks in a refraction analysis to derive a near‐surface velocity model. We have used turning‐ray tomography to model near‐surface velocities from seismic reflection profiles recorded in the Hueco Bolson of West Texas and southern New Mexico. The results of this analysis are interval‐velocity models for the upper 150 to 300 m of the seismic profiles which delineate geologic features that were not interpretable from the stacked records alone. In addition, the interval‐velocity models lead to improved time‐to‐depth conversion; when converted to stacking velocities, they may provide a better estimate of stacking velocities at early traveltimes than other methods.

scholarly journals Traveltime-based true-amplitude migration

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. S251-S259 ◽  
Author(s):  
Claudia Vanelle ◽  
Miriam Spinner ◽  
Thomas Hertweck ◽  
Christoph Jäger ◽  
Dirk Gajewski
Keyword(s):  
Image Quality ◽  
Ray Tracing ◽  
Seismic Reflection ◽  
Real Data ◽  
Weight Functions ◽  
Velocity Models ◽  
Kirchhoff Migration ◽  
Alternative Approach ◽  
Dynamic Ray Tracing ◽  
Structural Image

True-amplitude Kirchhoff migration (TAKM) is an important tool in seismic-reflection imaging. In addition to a structural image, it leads to reflectivity maps of the subsurface. TAKM is carried out in terms of a weighted diffraction stack where the weight functions are computed with dynamic ray tracing (DRT) in addition to the diffraction traveltimes. DRT, however, is time-consuming and imposes restrictions on the velocity models, which are not always acceptable. An alternative approach to TAKM is proposed in which the weight functions are directly determined from the diffraction traveltimes. Because other methods exist for the generation of traveltimes, this approach is not limited by the requirements for DRT. Applications to a complex synthetic model and real data demonstrate that the image quality and accuracy of the reconstructed amplitudes are equivalent to those obtained from TAKM with DRT-generated weight functions.

Spatial variations of magmatic crustal accretion during the opening of the Tyrrhenian back-arc from wide-angle seismic velocity models and seismic reflection images

2016 ◽  
Vol 30 ◽  
pp. 124-141 ◽  
Author(s):  
Manel Prada ◽  
Valenti Sallares ◽  
César R. Ranero ◽  
Montserrat G. Vendrell ◽  
Ingo Grevemeyer ◽  
...  
Keyword(s):  
Seismic Reflection ◽  
Seismic Velocity ◽  
Spatial Variations ◽  
Wide Angle ◽  
Crustal Accretion ◽  
Velocity Models ◽  
Back Arc

Mitigation of guided wave contamination in waveform tomography of marine seismic reflection data from southwestern Alaska

Geophysics ◽  
2016 ◽  
Vol 81 (4) ◽  
pp. B101-B118
Author(s):  
Rajesh Vayavur ◽  
Andrew J. Calvert
Keyword(s):  
Seismic Reflection ◽  
Guided Waves ◽  
Phase Error ◽  
Guided Wave ◽  
Logarithmic Phase ◽  
Seismic Reflection Data ◽  
Amplitude Inversion ◽  
Velocity Models ◽  
Waveform Tomography ◽  
Marine Seismic

We have applied 2D frequency-domain acoustic waveform tomography to two different sections of a marine seismic reflection line from southwest Alaska: one section with a deep igneous basement overlain by a thick pile of sediments and the other section with a shallow basement and a thin sedimentary cover. We have evaluated the appearance of dispersive guided waves on both sections, and we have determined that with appropriate data preconditioning it is possible to invert the data using 2D acoustic waveform tomography. Where the basement is deep, we first reduced the dispersive wave contamination of the seismic field data by trace editing, band-pass filtering, and careful choice of the data window for inversion. We then tested different objective functions and inversion scheduling before selecting an approach based on the logarithmic phase, which could be followed by joint phase and amplitude inversion. Where the basement is shallow, the starting model itself, which was generated by ray-based first-arrival tomography, generated acoustic guided waves, necessitating the use of an absorbing boundary condition at the free surface. Logarithmic phase inversion was used, but the amplitude inversion did not converge. To invert seismic data from both sections, we used a layer stripping strategy in which the gradient was used at each stage of the inversion process to check the corresponding model updates. Our results were validated by comparison between synthetic and observed waveforms, comparison of residual phase error plots for the initial and final velocity models, and comparison of waveform tomography velocity models with migrated images. Waveform tomography permits interpretation of the subsurface close to the seafloor where reflection images are contaminated by water-layer multiples, and we inferred the existence of a fault zone from a low-velocity anomaly within the igneous basement.

A unified approach to 3-D seismic reflection imaging, Part I: Basic concepts

Geophysics ◽  
1996 ◽  
Vol 61 (3) ◽  
pp. 742-758 ◽  
Author(s):  
Peter Hubral ◽  
Jörg Schleicher ◽  
Martin Tygel
Keyword(s):  
Time Domain ◽  
Seismic Reflection ◽  
Velocity Model ◽  
Unified Approach ◽  
Seismic Record ◽  
Kirchhoff Type ◽  
Velocity Models ◽  
Reflection Imaging ◽  
The Time Domain ◽  
Image Transformations

Given a 3-D seismic record for an arbitrary measurement configuration and assuming a laterally and vertically inhomogeneous, isotropic macro‐velocity model, a unified approach to amplitude‐preserving seismic reflection imaging is provided. This approach is composed of (1) a weighted Kirchhoff‐type diffraction‐stack integral to transform (migrate) seismic reflection data from the measurement time domain into the model depth domain, and of (2) a weighted Kirchhoff‐type isochrone‐stack integral to transform (demigrate) the migrated seismic image from the depth domain back into the time domain. Both the diffraction‐stack and isochrone‐stack integrals can be applied in sequence (i.e., they can be chained) for different measurement configurations or different velocity models to permit two principally different amplitude‐preserving image transformations. These are (1) the amplitude‐preserving transformation (directly in the time domain) of one 3-D seismic record section into another one pertaining to a different measurement configuration and (2) the transformation (directly in the depth domain) of a 3-D depth‐migrated image into another one for a different (improved) macro‐velocity model. The first transformation is referred to here as a “configuration transform” and the second as a “remigration.” Additional image transformations arise when other parameters, e.g., the ray code of the elementary wave to be imaged, are different in migration and demigration. The diffraction‐ and isochrone‐stack integrals incorporate a fundamental duality that involves the relationship between reflectors and the corresponding reflection‐time surfaces. By analytically chaining these integrals, each of the resulting image transformations can be achieved with only one single weighted stack. In this way, generalized‐Radon‐transform‐type stacking operators can be designed in a straightforward way for many useful image transformations. In this Part I, the common geometrical concepts of the proposed unified approach to seismic imaging are presented in simple pictorial, nonmathematical form. The more thorough, quantitative description is left to Part II.

Stereotomography of seismic data acquired on undulant topography

Geophysics ◽  
2018 ◽  
Vol 83 (4) ◽  
pp. U35-U41 ◽  
Author(s):  
Changkun Jin ◽  
Jianzhong Zhang
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Synthetic Data ◽  
Topographic Effects ◽  
Seismic Reflection Data ◽  
West China ◽  
Depth Migration ◽  
Velocity Models ◽  
Reflection Data ◽  
Rugged Topography

Stereotomography is a robust method for building velocity models from seismic reflection data, and it has been applied to offshore seismic data, but there is almost no stereotomographic study with rugged topographic conditions. We study the topographic effects on the slopes of locally coherent events of seismic data and develop an approach to calculate the slopes on an undulant observation surface using the horizontal and vertical components of slowness vectors estimated. Then, we develop an extended stereotomography with undulant observation surface based on the conventional one. Tests on synthetic data validate the extended stereotomography. Application to the field seismic data in a foothill belt in Xinjiang of the West China indicates that the extended stereotomography is an effective tool to build velocity models for prestack depth migration of seismic data acquired on rugged topography.

scholarly journals ​Near-Surface High Resolution Characterization of the Seismogenic Alhama de Murcia Strike-slip Fault 

2021 ◽  
Author(s):  
Handoyo Handoyo ◽  
Imma Palomeras ◽  
Juan Alcalde ◽  
Irene de Felipe ◽  
David Martí ◽  
...  
Keyword(s):  
Seismic Reflection ◽  
Broad Band ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Fault System ◽  
Seismogenic Zone ◽  
Maximum Magnitude ◽  
Near Surface ◽  
Velocity Models ◽  
Seismic Reflection Profiles

<p><span><span>In Spring 2011 (11</span><sup><span>th</span></sup><span> of May), the vicinity of Lorca city (Murcia, SE Iberian Peninsula) was hit by two main seismic shocks that reach a maximum magnitude of 5.2 Mw. The earthquake caused serious widespread damage in the city and its surroundings. Similar events have affected the area regularly in the past (for example: on May 6,</span><sup></sup><span>1977, 4.2 mg). These events are distributed along a relatively broad band (roughly NE-SW oriented) parallel to the coast,</span> <span>associated to the activation of the Alhama de Murcia Fault (AMF), an oblique-slip (reverse-strike-slip) fault system located in the Eastern Betics Shear Zone. The current study aims to characterize the shallow subsurface across some of the surface outcrop of a few of the main faults that lie within this seismogenic strike-slip fault system. Six normal-incidence seismic reflection profiles were acquired in the area crossing the AMF and the Carrascoy fault, among others). This study focuses on the determination of the shear-wave velocity depth model by applying Multichannel Analysis of Surface Waves (MASW), using the shot records of the seismic reflection profiles. The 1D velocity-depth functions acquired were pasted together to obtain the final 2D velocity models. The hand-picked dispersion curves were inverted using two different approaches to address the consistency of the inversion schemes. The final models reveal relevant differences across the different fault zones, reflecting the heterogeneity and lateral variability that characterizes a complex seismogenic zone, a most probably, diffuse plate boundary.</span></span></p><p><span><span>This research is supported by: Generalitat de Catalunya (AGAUR) grant 2017SGR1022 (GREG); EU (H2020) 871121 (EPOS-SP); EIT-RawMaterials 17024 (SIT4ME), </span></span><strong><span><span>CGL2013-47412-C2-1-P</span></span></strong><span><span>. </span></span></p>

scholarly journals Laterally constrained inversion of ground roll from seismic reflection records

Geophysics ◽  
2009 ◽  
Vol 74 (6) ◽  
pp. G35-G45 ◽  
Author(s):  
Laura Valentina Socco ◽  
Daniele Boiero ◽  
Sebastiano Foti ◽  
Roger Wisén
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Seismic Reflection ◽  
Dispersion Curves ◽  
Inversion Algorithm ◽  
Seismic Reflection Data ◽  
Velocity Models ◽  
Reflection Data ◽  
Quality Dispersion

Seismic reflection data contain surface waves that can be processed and interpreted to supply shear-wave velocity models along seismic reflection lines. The coverage of seismic reflection data allows the use of automated multifold processing to extract high-quality dispersion curves and experimental uncertainties in a moving spatial window. The dispersion curves are then inverted using a deterministic, laterally constrained inversion to obtain a pseudo-2D model of the shear-wave velocity. A Monte Carlo global search inversion algorithm optimizes the parameterization. When the strategy is used with synthetic and field data, consistent final models with smooth lateral variations are successfully retrieved. This method constitutes an improvement over the individual inversion of single dispersion curves.

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