Cross-gradient Joint Inversion Of 2d Resistivity And Seismic Refraction Methods
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Date
2021-10
Authors
Nabilah Husna Binti Abdullah Sanusi
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia.
Abstract
Subsurface investigation commonly involved geophysical methods such as
2D resistivity and seismic refraction methods. Each methods are dependent on
different physical parameters and has different sensitivity on subsurface structure. In
this study, joint inversion with a cross-gradient constraint method was conducted to
map and improved image characterization of lateral and vertical subsurface variation.
The basic idea of this approach was to achieve a unified geological model which
satisfies both data sets using cross-gradient constraint. This method was conducted
on five synthetic models with lateral subsurface variation (Model 1, Model 2, and
Model 3) and vertical subsurface variation (Model 4 and Model 5) as preliminary
studies. Then, this method was applied to the study areas with lateral subsurface
variation (Bunker USM, Tapak Konvo USM, and Guar Jentik) and vertical
subsurface variation (Indah Kembara and Bukit Chondong). Particle size distribution
(PSD) and X-ray diffraction (XRD) analysis were also conducted on soil and rock
samples at Indah Kembara, Guar Jentik, and Bukit Chondong. Cross-gradient joint
inversion of seismic model with lateral subsurface variation shows structural
improvement of the anomaly. Meanwhile, separate inversion models with vertical
subsurface variation already show structural similarities, hence no changes in both
cross-gradient joint inversion models. Lateral subsurface variation such as Bunker
USM and Tapak Konvo USM shows a structural improvement of the bunker (<40
Ωm, 1.4 - 1.6 km/s) and drain (< 50 Ωm, <0.9 km/s) in joint inversion of seismic
models.
Description
Keywords
Cross-gradient Joint Inversion , 2d Resistivity And Seismic Refraction Methods