The internal structure of sand bars on the Colorado River, Grand Canyon, as determined by ground-penetrating radar

2001 ◽  
Author(s):  
Walter A. Barnhardt ◽  
Robert Kayen ◽  
David Rubin ◽  
Diane L. Minasian
Keyword(s):  
Internal Structure ◽  
Ground Penetrating Radar ◽  
Colorado River ◽  
Grand Canyon ◽  
Sand Bars ◽  
Ground Penetrating

Imaging the internal structure of trunks via multiscale phase inversion of ground-penetrating radar data

2021 ◽  
pp. 1-53
Author(s):  
Lei Fu ◽  
Lanbo Liu
Keyword(s):  
Dielectric Constant ◽  
Internal Structure ◽  
Ground Penetrating Radar ◽  
Phase Inversion ◽  
Multiscale Approach ◽  
White Oak ◽  
Near Surface ◽  
Oak Tree ◽  
Ground Penetrating ◽  
Constant Distribution

Ground-penetrating radar (GPR) is a geophysical technique widely used in near-surface non-invasive detecting. It has the ability to obtaining a high-resolution internal structure of living trunks. Full wave inversion (FWI) has been widely used to reconstruct the dielectric constant and conductivity distribution for cross-well application. However, in some cases, the amplitude information is not reliable due to the antenna coupling, radiation pattern and other effects. We present a multiscale phase inversion (MPI) method, which largely matches the phase information by normalizing the magnitude spectrum; in addition, a natural multiscale approach by integrating the input data with different times is implemented to partly mitigate the local minimal problem. Two synthetic GPR datasets generated from a healthy oak tree trunk and from a decayed trunk are tested by MPI and FWI. Field GPR dataset consisting of 30 common shot GPR data are acquired on a standing white oak tree (Quercus alba); the MPI and FWI methods are used to reconstruct the dielectric constant distribution of the tree cross-section. Results indicate that MPI has more tolerance to the starting model, noise level and source wavelet. It can provide a more accurate image of the dielectric constant distribution compared to the conventional FWI.

scholarly journals Reverse-time migration for evaluating the internal structure of tree-trunks using ground-penetrating radar

2020 ◽  
Vol 115 ◽  
pp. 102294 ◽  
Author(s):  
Amir M. Alani ◽  
Iraklis Giannakis ◽  
Lilong Zou ◽  
Livia Lantini ◽  
Fabio Tosti
Keyword(s):  
Internal Structure ◽  
Ground Penetrating Radar ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Time Migration ◽  
Ground Penetrating

scholarly journals Imaging the structure of cave ice by ground-penetrating radar

2011 ◽  
Vol 5 (2) ◽  
pp. 329-340 ◽  
Author(s):  
H. Hausmann ◽  
M. Behm
Keyword(s):  
Electromagnetic Wave ◽  
Internal Structure ◽  
Liquid Water ◽  
Ground Penetrating Radar ◽  
Wave Speed ◽  
Liquid Water Content ◽  
Thin Layers ◽  
Ice Formation ◽  
Alpine Regions ◽  
Ground Penetrating

Abstract. Several caves in high elevated alpine regions host up to several meters thick ice. The age of the ice may exceed some hundreds or thousands of years. However, structure, formation and development of the ice are not fully understood and are subject to relatively recent investigation. The application of ground-penetrating radar (GPR) enables to determine thickness, volume, basal and internal structure of the ice and provides as such important constraints for related studies. We present results from four caves located in the Northern Calcareous Alps of Austria. We show that the ice is far from being uniform. The base has variable reflection signatures, which is related to the type and size of underlying debris. The internal structure of the cave ice is characterized by banded reflections. These reflection signatures are interpreted as thin layers of sediments and might help to understand the ice formation by representing isochrones. Overall, the relatively low electromagnetic wave speed suggests that the ice is temperate, and that a liquid water content of about 2% is distributed homogenously in the ice.

scholarly journals Ground-penetrating radar profiling on embanked floodplains

2007 ◽  
Vol 86 (1) ◽  
pp. 55-61 ◽  
Author(s):  
M.A.J. Bakker ◽  
D. Maljers ◽  
H.J.T. Weerts
Keyword(s):  
Ground Penetrating Radar ◽  
Sedimentary Facies ◽  
Extreme Floods ◽  
Architectural Elements ◽  
Accommodation Space ◽  
Sand Bars ◽  
Sediment Deposits ◽  
Radar Velocity ◽  
Ground Penetrating ◽  
Radar Facies

AbstractManagement of the Dutch embanked floodplains is of crucial interest in the light of a likely increase of extreme floods. One of the issues is a gradual decrease of floodwater accommodation space as a result of overbank deposition of mud and sand during floods. To address this issue, sediment deposits of an undisturbed embanked floodplain near Winssen along the river Waal were studied using ground-penetrating radar (GPR). A number of radar facies units were recognized. Boreholes were used to relate radar facies units to sedimentary facies and to determine radar velocity. The GPR groundwave is affected by differences in moisture and texture of the top layer and probably interferes with the first subsurface reflector. The architectural elements recognized in the GPR transects confirm earlier reported insights on human-influenced river behaviour. This is testified in the development of sand bars during flood regimes that are probably more widespread than previously established.

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