Imaging With Ambient Seismic Noise

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Imaging With Ambient Seismic Noise

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Author : Jason P. Chang
language : en
Publisher:
Release Date : 2018

Imaging With Ambient Seismic Noise written by Jason P. Chang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.

Whether due to naturally occurring or human-generated vibrations, the ground is never truly at rest. Though individual recordings of these vibrations appear to be noisy, there are actually spatially coherent seismic signals hidden in them. By having two receivers record this ambient seismic noise continuously and simultaneously, it is possible to extract these hidden signals with a method called passive seismic interferometry, which effectively transforms one of the receivers into a seismic source. Thus, when performed on an array of receivers, passive seismic interferometry can produce an entire virtual seismic survey at a fraction of the cost of a traditional seismic survey with active sources. These virtual responses between receivers can then be used to image the subsurface. A number of studies have successfully implemented passive seismic interferometry. However, the vast majority of them focus on extracting low-frequency microseism surface waves, which are generated by the interaction of ocean waves and the subsequent pressure variations along the sea-bottom. Though the resulting high-resolution subsurface velocity maps from these studies are impressive, they do not demonstrate the full potential of passive seismic interferometry. Hence, the goal of this thesis is to demonstrate the ability of passive seismic interferometry to extract more than just microseism surface waves. To do so, I apply the technique to three industry-scale seismic arrays located in three different environments. I first focus on urban ambient seismic noise recorded by a dense seismic array in Long Beach, California. In this environment, passive seismic interferometry using continuous recordings between 3 4 Hz extracts Rayleigh waves originating from these local roads. After tailoring my Rayleigh-wave traveltime selection criteria to account for the presence of noise sources within the array, I invert the traveltimes to produce near-surface group velocity maps that reveal structures that coincide well with those in geologic maps, including the Newport-Inglewood fault. I then switch to a shallow-water ocean-bottom node array in the North Sea to show that passive seismic interferometry can extract P-waves propagating through the water column in the ambient seismic noise field between 40 200 Hz. Examination of the virtual responses between receivers over time reveals that the major sources of seismic energy at these high frequencies are distant shipping noise and the operating platform in the center of the array. Based on the successful extraction of P-waves, I aim to extract 1D reflection profiles from the continuous data by effectively performing seismic interferometry using ambient seismic noise after up- and down-going wavefield separation. Finally, I work with ambient seismic noise recorded by a deep-water, long-offset ocean-bottom node array offshore Norway. Because of the length of the array, I focus on continuous recordings below 2 Hz, which is the microseism band. Though passive seismic interferometry in this environment extracts the commonly observed Scholte waves, it also extracts two other wave modes that have rarely been observed in ambient seismic noise. One is acoustic guided waves, which can be used to produce 1D P-wave velocity profiles. The other is critical refractions, which have never been observed in ambient seismic noise before and can potentially be used for tomography. Because of the novelty of this observation, I model one hypothesis for the natural generation of critical refractions.

Seismic Ambient Noise

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Author : Nori Nakata
language : en
Publisher: Cambridge University Press
Release Date : 2019-03-21

Seismic Ambient Noise written by Nori Nakata and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-03-21 with Nature categories.

A comprehensive overview of seismic ambient noise, covering observations, physical origins, modelling, processing methods and applications in imaging and monitoring.

Seismic Imaging And Monitoring In Mines With Ambient Seismic Noise Correlations

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Author : Gerrit Olivier
language : en
Publisher:
Release Date : 2015

Seismic Imaging And Monitoring In Mines With Ambient Seismic Noise Correlations written by Gerrit Olivier and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.

This work focus on using passive noise-based seismic methods to image and monitor the rock mass in underground mines. The main results show that it is possible to gain benefit from the diffuse ambient seismic field in mines to 1/ image the rock mass and 2/ monitor its mechanical property changes over time. This work opens a way to improve safety in deep underground mines.

Imaging New Zealand S Crustal Structure Using Ambient Seismic Noise Recordings From Permanent And Temporary Instruments

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Author : Yannik D. Behr
language : en
Publisher:
Release Date : 2011

Imaging New Zealand S Crustal Structure Using Ambient Seismic Noise Recordings From Permanent And Temporary Instruments written by Yannik D. Behr and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Geology, Structural categories.

Passive Imaging With Ambient Noise

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Author : Josselin Garnier
language : en
Publisher: Cambridge University Press
Release Date : 2016-04-21

Passive Imaging With Ambient Noise written by Josselin Garnier and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-04-21 with Computers categories.

This multidisciplinary book provides a systematic introduction to the analysis of passive sensor array imaging using ambient noise sources.

Imaging Major Canadian Sedimentary Basins And Their Adjacent Structures Using Ambient Seismic Noise And Other Applications Of Seismic Noise

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Author : Ayodeji Paul Kuponiyi
language : en
Publisher:
Release Date : 2021

Imaging Major Canadian Sedimentary Basins And Their Adjacent Structures Using Ambient Seismic Noise And Other Applications Of Seismic Noise written by Ayodeji Paul Kuponiyi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.

Over a decade ago, it was discovered that the earth's natural seismic wavefields, propagating as seismic noise, can be processed using correlation methods to produce surface waves, similar to those generated by earthquakes. This discovery represents a paradigm shift in seismology and has led to several tomographic studies of earth structures, at different scales and resolutions, in previously difficult-to-study areas around the world. This PhD dissertation presents research results on multi-scale and multi-purpose applications of ambient seismic noise wavefields under three topics: (1) Imaging of sedimentary basins and sub-basin structures in eastern and western Canada using ambient seismic noise, (2) Combining measurements from ambient seismic noise with earthquake datasets for imaging crustal and mantle structures, and (3) Temporal variation in cultural seismic noise and noise correlation functions (NCFs) during the COVID-19 lockdown in Canada. The first topic involved imaging the sedimentary basins in eastern and western Canada using shear wave velocities derived from ambient noise group velocities. The results show that the basins are characterized by varying depths, with maximums along the studied cross-sections in excess of 10 km, in eastern and western Canada. Characteristics of accreted terranes in eastern and western Canada are also revealed in the results. A seismically distinct basement is imaged in eastern Canada and is interpreted to be a vestige of the western African crust trapped beneath eastern Canada at the opening of the Atlantic Ocean. In western Canada, the 3D variation of the Moho and sedimentary basin depths is imaged. The thickest sediments in eastern Canada are found beneath the Queen Charlotte, Williston and the Alberta Deep basins, while the Moho is the deepest beneath the Williston basin and parts of Alberta basin and northern British Columbia. For the second topic, I worked on improving the seismological methodology to construct broadband (period from 2 to 220 s) dispersion curves by combining the dispersion measurements derived from ambient seismic noise with those from earthquakes. The broadband dispersion curves allow for imaging earth structures spanning the shallow crust to the upper mantle. For the third topic, I used ambient seismic data from the earlier stages of the COVID-19 pandemic to study the temporal variation of seismic power spectra and the potential impacts of COVID-19 lockdown on ambient NCFs in four cities in eastern and western Canada. The results show mean seismic power drops of 24% and 17% during the lockdown in eastern Canada, near Montreal and Ottawa respectively and reductions of 27% and 17% near Victoria and Sidney respectively. NCF signal quality within the secondary microseism band reached maximum before the lockdown, minimum during lockdown and at intermediate levels during the gradual reopening phase for the western Canada station pair.

Encyclopedia Of Solid Earth Geophysics

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Author : Harsh Gupta
language : en
Publisher: Springer Science & Business Media
Release Date : 2011-06-29

Encyclopedia Of Solid Earth Geophysics written by Harsh Gupta and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-06-29 with Science categories.

The past few decades have witnessed the growth of the Earth Sciences in the pursuit of knowledge and understanding of the planet that we live on. This development addresses the challenging endeavor to enrich human lives with the bounties of Nature as well as to preserve the planet for the generations to come. Solid Earth Geophysics aspires to define and quantify the internal structure and processes of the Earth in terms of the principles of physics and forms the intrinsic framework, which other allied disciplines utilize for more specific investigations. The first edition of the Encyclopedia of Solid Earth Geophysics was published in 1989 by Van Nostrand Reinhold publishing company. More than two decades later, this new volume, edited by Prof. Harsh K. Gupta, represents a thoroughly revised and expanded reference work. It brings together more than 200 articles covering established and new concepts of Geophysics across the various sub-disciplines such as Gravity, Geodesy, Geomagnetism, Seismology, Seismics, Deep Earth Processes, Plate Tectonics, Thermal Domains, Computational Methods, etc. in a systematic and consistent format and standard. It is an authoritative and current reference source with extraordinary width of scope. It draws its unique strength from the expert contributions of editors and authors across the globe. It is designed to serve as a valuable and cherished source of information for current and future generations of professionals.

Imaging Volcanic Systems Using The Ambient Seismic Field

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Author : Kevin Joseph Seats
language : en
Publisher:
Release Date : 2015

Imaging Volcanic Systems Using The Ambient Seismic Field written by Kevin Joseph Seats and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.

With recent scientific advances, and bettering of computers, seismic imaging has taken monumental steps forward. Cross-correlating ambient seismic noise, for instance, is now capable of providing as much, if not more, reliable information about the subsurface than traditional tomographic imaging, which required large, easily observable signals to measure seismic wavespeeds through regions of interest. This traditional technique typically suffers from an inherent bias in places that can be imaged (due to local seismicity), and places that cannot be imaged (due to a lack of seismicity). In this thesis, I advance the processing used to extract coherent energy, and therefore information, from the ambient seismic field, rather than known large signals. Doing this provides a novel way to image a region of the crust without waiting for large signals. In bettering this methodology, I seek to provide more stable Noise Correlation Functions (NCFs) than had ever been obtained before, using as little seismic data as possible. I then use this advancement to seismically image two volcanic settings: the Yellowstone Volcanic Field, and the Sierra Negra shield volcano in the Galapagos Islands. Through this three-dimensional ambient noise tomography, I provide highresolution images of the subsurface structure at these regions. Then, to further improve depth resolution of my imaging at Yellowstone, I jointly invert the ambient noise tomographic results with teleseismic receiver function analysis. Finally, due to the temporal stability of the NCFs, I analyze and observe time-lapsed ambient noise tomographic images at Yellowstone.

Seismic Interferometry

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Author : Deyan Draganov
language : en
Publisher: SEG Books
Release Date : 2008

Seismic Interferometry written by Deyan Draganov and has been published by SEG Books this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with Nature categories.

Including more than 70 papers, this invaluable source for researchers and students contains an editors' introduction with extensive references and chapters on seismic interferometry without equations, highlights of the history of seismic interferometry from 1968 until 2003, and offers a detailed overview of the rapid developments since 2004.

Passive Imaging And Characterization Of The Subsurface With Distributed Acoustic Sensing

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Author : Eileen Rose Martin
language : en
Publisher:
Release Date : 2018

Passive Imaging And Characterization Of The Subsurface With Distributed Acoustic Sensing written by Eileen Rose Martin and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.

Active seismic surveys for subsurface imaging are expensive and logistically difficult in populated areas where they have potential to impact day-to-day life, so continuous monitoring experiments are rarely done. I combine two methods to make continuous subsurface monitoring cheaper: estimating wave equation Green's functions from passive vibration recordings, and measuring meter-scale strain rate profiles along fiber optic cables which may already exist in urban areas or can easily be installed. These methods may make continuous high-resolution subsurface imaging possible where it was not previously, but there are challenges. The shift from particle velocity data of seismometers to axial strain rates recorded by fibers leads to different responses to the same source. Additionally, signals extracted from ambient seismic noise interferometry are masked by a fundamentally different receiver response. I use data from multiple fiber optic surface arrays: two with fiber directly coupled to the ground intended for permafrost thaw monitoring, and one with fiber sitting loosely in existing telecommunications conduits. Although these data look different, the arrival times of earthquakes at known times verify that the arrays record vibrations over a wide range of frequencies. Care must be taken to understand and mitigate the effects of non-ideal anthropogenic noise when doing ambient seismic noise in urban areas and around infrastructure. I use interferometry to extract repeatable signals for near-surface geotechnical characterization near infrastructure, even between fiber channels that are not collinear. I investigate temporal stability and changes in signals extracted throughout large arrays in the presence of a changing subsurface and noise field. As ambient noise practitioners begin using denser arrays, the typical cross-correlation process can become expensive, so I propose a new algorithm for dispersion image calculation that is an order of magnitude faster and parallelizable.