Near-surface Characterization Via Seismic Surface-wave Inversion

Near-surface Characterization Via Seismic Surface-wave Inversion
Title Near-surface Characterization Via Seismic Surface-wave Inversion PDF eBook
Author Soumya Roy
Publisher
Pages
Release 2013
Genre Geophysics
ISBN

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Characterization of the near-surface is important in identifying shallow properties and structures. In this dissertation, special emphasis is placed on estimating near-surface shear (S)-wave velocities (V_S) which can be used for exploration seismology as well as geotechnical purposes; and even for planetary studies. A frequency-based surface-wave (Rayleigh-wave or ground-roll) inversion method (MASW: Multichannel Analysis of Surface Waves) has been used to estimate 1D and 2D S-wave velocities. The method has been applied on varied seismic datasets related to numerical modeling, physical modeling, and field surveys. The field seismic datasets are from different geological settings and geographical locations: 1) La Marque, Texas, 2) Barringer (Meteor) Crater, Arizona, 3) YBRA field camp, Montana, 4) Hockley fault survey, Texas, and 5) Bradford, Pennsylvania. Estimated S-wave velocities range from as low as 100-300 m/s (La Marque, Hockley) to as high as 3400-3500 m/s (physical model: blank glass block). For the Meteor Crater survey, an unconsolidated near-surface structure (ejecta-blanket) and its thinning thickness trend (thickness decreasing from 20 m to 5 m) has been successfully identified using 2D V_S structure (400-1200 m/s). The depths of investigation for S-wave velocities vary from only 10 m (Hockley survey) to 180 m (Bradford survey) depending on acquisition geometries and source types. Apart from the identification of geological structures; S-wave velocities have been used to calculate S-wave statics and predict densities. The long-wavelength S-wave statics have been calculated for Bradford and Meteor Crater surveys. The densities have been successfully predicted from V_S for modeling experiments and field data (Bradford and YBRA surveys). All predicted densities are consistent with known values with a maximum error of 6%. The effect of lateral heterogeneity on MASW has also been evaluated using different numerical and physical models (dipping layers varying from 10℗ð to 90℗ð). MASW works well for gentle heterogeneity but provides smeared velocity structures for sharp heterogeneities (physical model experiment and Hockley fault survey). A basic full-waveform inversion scheme has been applied on a numerical model with a vertical interface (i.e. 90℗ð dip) showing its potential to handle lateral heterogeneity problems.

Surface Wave Analysis for Near Surface Applications

Surface Wave Analysis for Near Surface Applications
Title Surface Wave Analysis for Near Surface Applications PDF eBook
Author Giancarlo Dal Moro
Publisher Elsevier
Pages 253
Release 2014-11-04
Genre Science
ISBN 0128011408

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Seismic Wave Analysis for Near Surface Applications presents the foundational tools necessary to properly analyze surface waves acquired according to both active and passive techniques. Applications range from seismic hazard studies, geotechnical surveys and the exploration of extra-terrestrial bodies. Surface waves have become critical to near-surface geophysics both for geotechnical goals and seismic-hazard studies. Included in this book are the related theories, approaches and applications which the lead editor has assembled from a range of authored contributions carefully selected from the latest developments in research. A unique blend of theory and practice, the book’s concepts are based on exhaustive field research conducted over the past decade from the world’s leading seismologists and geophysicists. Edited by a geophysicist with nearly 20 years of experience in research, consulting, and geoscience software development Nearly 100 figures, photographs, and examples aid in the understanding of fundamental concepts and techniques Presents the latest research in seismic wave characteristics and analysis, the fundamentals of signal processing, wave data acquisition and inversion, and the latest developments in horizontal-to-vertical spectral ratio (HVSR) Each chapter features a real-world case study—13 in all—to bring the book’s key principles to life

Surface Wave Methods for Near-Surface Site Characterization

Surface Wave Methods for Near-Surface Site Characterization
Title Surface Wave Methods for Near-Surface Site Characterization PDF eBook
Author Sebastiano Foti
Publisher CRC Press
Pages 492
Release 2014-08-21
Genre Technology & Engineering
ISBN 0415678765

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Develop a Greater Understanding of How and Why Surface Wave Testing Works Using examples and case studies directly drawn from the authors’ experience, Surface Wave Methods for Near-Surface Site Characterization addresses both the experimental and theoretical aspects of surface wave propagation in both forward and inverse modeling. This book accents the key facets associated with surface wave testing for near-surface site characterization. It clearly outlines the basic principles, the theoretical framework and the practical implementation of surface wave analysis. In addition, it also describes in detail the equipment and measuring devices, acquisition techniques, signal processing, forward and inverse modeling theories, and testing protocols that form the basis of modern surface wave techniques. Review Examples of Typical Applications for This Geophysical Technique Divided into eight chapters, the book explains surface wave testing principles from data measurement to interpretation. It effectively integrates several examples and case studies illustrating how different ground conditions and geological settings may influence the interpretation of data measurements. The authors accurately describe each phase of testing in addition to the guidelines for correctly performing and interpreting results. They present variants of the test within a consistent framework to facilitate comparisons, and include an in-depth discussion of the uncertainties arising at each stage of surface wave testing. Provides a comprehensive and in-depth treatment of all the steps involved in surface wave testing Discusses surface wave methods and their applications in various geotechnical conditions and geological settings Explains how surface wave measurements can be used to estimate both stiffness and dissipative properties of the ground Addresses the issue of uncertainty, which is often an overlooked problem in surface wave testing Includes examples with comparative analysis using different processing techniques and inversion algorithms Outlines advanced applications of surface wave testing such as joint inversion, underwater investigation, and Love wave analysis Written for geotechnical engineers, engineering seismologists, geophysicists, and researchers, Surface Wave Methods for Near-Surface Site Characterization offers practical guidance, and presents a thorough understanding of the basic concepts.

Advances in Near-surface Seismology and Ground-penetrating Radar, Volume 15

Advances in Near-surface Seismology and Ground-penetrating Radar, Volume 15
Title Advances in Near-surface Seismology and Ground-penetrating Radar, Volume 15 PDF eBook
Author Richard D. Miller
Publisher SEG Books
Pages 513
Release 2010-01-11
Genre Science
ISBN 1560802243

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Advances in Near-surface Seismology and Ground-penetrating Radar (SEG Geophysical Developments Series No. 15) is a collection of original papers by renowned and respected authors from around the world. Technologies used in the application of near-surface seismology and ground-penetrating radar have seen significant advances in the last several years. Both methods have benefited from new processing tools, increased computer speeds, and an expanded variety of applications. This book, divided into four sections--"Reviews," "Methodology," "Integrative Approaches," and "Case Studies"--Captures the most significant cutting-edge issues in active areas of research, unveiling truly pertinent studies that address fundamental applied problems. This collection of manuscripts grew from a core group of papers presented at a post-convention workshop, "Advances in Near-surface Seismology and Ground-penetrating Radar," held during the 2009 SEG Annual Meeting in Houston, Texas. This is the first cooperative publication effort between the near-surface communities of SEG, AGU, and EEGS. It will appeal to a large and diverse audience that includes researchers and practitioners inside and outside the near-surface geophysics community. --Publisher description.

Advancements in 1D and 2D Near-surface Seismic Site Characterization Using Surface Waves and Full Waveform Inversion

Advancements in 1D and 2D Near-surface Seismic Site Characterization Using Surface Waves and Full Waveform Inversion
Title Advancements in 1D and 2D Near-surface Seismic Site Characterization Using Surface Waves and Full Waveform Inversion PDF eBook
Author Michael Benjamin Schutt Yust
Publisher
Pages 0
Release 2022
Genre
ISBN

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Seismic site characterization is a critical part of understanding earthquake hazards in geotechnical engineering. This is often accomplished through various invasive and non-invasive methods for measuring shear-wave velocity (Vs) in-situ, as it is directly related to small-strain shear modulus. For civil engineering applications, the seismic conditions of the near surface (top 30 m) are of particular interest. Surface wave testing has become the tool of choice for many engineers due to its flexibility, efficiency, and ability to characterize a wide variety of subsurface conditions. Surface wave testing is also particularly well suited to near-surface imaging due to the prevalence of surface waves within the elastic wavefield at shallow depths. Surface wave testing, however, is not without limitations. Inversion of surface wave dispersion data is ill-posed and non-unique, meaning that when it is performed rigorously with full consideration of epistemic uncertainty, a potentially large number of reasonable and different 1D Vs profiles are produced. This presents a challenge of evaluating which profiles should be used for further analysis or design. Additionally, engineers often desire information about the lateral variability of seismic parameters in the subsurface, but the inherently 1D nature of the processing and inversion techniques used in surface wave testing make acquiring this information challenging. Evaluation of lateral variability is generally accomplished through multiple individual 1D surface wave analyses across the site, providing only pseudo-2D information. This also introduces a new challenge: how to collect the large amount of experimental data required for multiple analyses as the efficiency of traditional surface wave acquisition is limited by the need to physically move geophone arrays with limited numbers of sensors. This dissertation discusses these challenges and presents potential solutions through the application of the DeltaVs method, distributed acoustic sensing, and full waveform inversion

Land Seismic Case Studies for Near-Surface Modeling and Subsurface Imaging

Land Seismic Case Studies for Near-Surface Modeling and Subsurface Imaging
Title Land Seismic Case Studies for Near-Surface Modeling and Subsurface Imaging PDF eBook
Author Öz Yilmaz
Publisher SEG Books
Pages 1056
Release 2021-06-30
Genre Science
ISBN 1560803800

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Written for practicing geophysicists, “Land Seismic Case Studies for Near-Surface Modeling and Subsurface Imaging” is a comprehensive guide to understanding and interpreting seismic data. The culmination of land seismic data acquisition and processing projects conducted by the author over the last two decades, this book contains more than nearly 800 figures from worldwide case studies—conducted in both 2D and 3D. Beginning with Chapter 1 on seismic characterization of the near-surface, Chapter 2 presents near-surface modeling by traveltime and full-wave inversion, Chapter 3 presents near-surface modeling by imaging, and then Chapter 4 includes detailed case studies for near-surface modeling. Chapter 5 reviews single- and multichannel signal processing of land seismic data with the key objective of removing surface waves and guided waves that are characterized as coherent linear noise. Uncommon seismic data acquisition methods, including large-offset acquisition in thrust belts to capture the large-amplitude supercritical reflections, swath-line acquisition, and joint PP and SH- SH seismic imaging are highlighted in Chapter 6, and Chapter 7 presents image-based rms velocity estimation and discusses the problem of velocity uncertainty. The final two chapters focus exclusively on case studies: 2D in Chapter 8 and 3D in Chapter 9. An outstanding teaching tool, this book includes analysis workflows containing processing steps designed to solve specific problems. Essential for anyone involved in acquisition, processing, and inversion of seismic data, this volume will become the definitive reference for understanding how the variables in seismic acquisition are directly reflected in the data.

The Microtremor Survey Method

The Microtremor Survey Method
Title The Microtremor Survey Method PDF eBook
Author Hiroshi Okada
Publisher SEG Books
Pages 150
Release 2003
Genre Science
ISBN 1560801204

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Describes the nature of the microtremor noise field, the use of appropriate surface arrays of geophones, and the two principal classes of array-processing techniques, high-resolution beamforming and the spatial autocorrelation method (SPAC). This is the first comprehensive textbook of the microtremor survey method written in English.