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@PHDTHESIS{Mozaffari:907641,
author = {Mozaffari, Amirpasha},
title = {{T}owards 3{D} crosshole {GPR} full-waveform inversion},
volume = {574},
school = {RWTH Aachen University},
type = {Dissertation},
reportid = {FZJ-2022-02120},
isbn = {978-3-95806-623-6},
series = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
Umwelt / Energy $\&$ Environment},
pages = {viii, 122},
year = {2022},
note = {Dissertation, RWTH Aachen University, 2022},
abstract = {High-resolution imaging of the subsurface improves our
understanding of thesubsurface flow and solute
transportation that can directly help us protectgroundwater
resources and remediate contaminated sites. The ground
penetratingradar (GPR) is a useful non/minimal invasive
method that consists of a transmitter(Tx) unit that emits
electromagnetic (EM) waves and a receiver (Rx) that
measuresthe arriving electromagnetic waves and can provide
high-resolution tomograms of thesubsurface properties.In
specific, the crosshole GPR setup in which two-neighbouring
boreholes are placedin the earth can provide much more
in-depth access to the target area. However,
theinterpretation of the GPR data remains challenging. The
simpler ray-based inversion(RBI) is computationally
attractive while fail to provide high-resolution tomogramsas
the results always smoothed over the target area. The
full-waveform inversion(FWI) can provide detailed subsurface
tomograms that can carry up to more thanan order of the
magnitude resolution compared to RBI from the same data set.
Asophisticated method such as FWI requires detailed
modelling tools and powerfulinversion algorithm that needs
significant computational resources. In last decades,
byexponential increase in computing power and the memory,
alongside to wider usage ofhigh performance computing
resources; FWI application in GPR data gain popularity.All
these computational advances such as FWI method. could be
very demandingto be modelled in 3D domain. Thus, some
fundamentals assumptions are made toreduce the computational
requirements, especially computational time and
requiredmemory by using 2D modeling domain. Despite the
usefulness of these simplifications,these assumptions led to
introducing inaccuracy that compromises the performanceof
the FWI in complex structures. We investigated the effect of
the assumption thatenables us to use a 2D model instead of a
computationally expensive 3D modelling tosimulate the EM
propagation. These assumptions are made for specific state
that notnecessary is always valid, and therefore it can
introduce inaccuracies in transferreddata. Study of several
synthetic cases revealed that the performance of the 3D to
2Dtransformation in complex structures such as high contrast
layer is much lower thanwhat is anticipated. Therefore, in
the complex subsurface system; 2D transferreddata inherently
carry inaccuracy that jeopardises the accuracy of any
further analysissuch as FWI. Thus, we introduced a FWI that
utilise a native 3D forward model touse the original
measured 3D data. The novel method is called 2.5D FWI, and
itshowed improvements compared to 2D FWI for synthetic and
measured data},
cin = {IBG-3},
cid = {I:(DE-Juel1)IBG-3-20101118},
pnm = {2173 - Agro-biogeosystems: controls, feedbacks and impact
(POF4-217)},
pid = {G:(DE-HGF)POF4-2173},
typ = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
urn = {urn:nbn:de:0001-2022052307},
url = {https://juser.fz-juelich.de/record/907641},
}