Geophysical Survey on the Coast of Peru: The Early Prehispanic City of Gallinazo Group in the Viru Valley

2014 ◽  
Vol 25 (3) ◽  
pp. 239-255 ◽  
Author(s):  
Jean-François Millaire ◽  
Edward Eastaugh

Recent geophysical survey at the early urban center of the Gallinazo Group in the Virú Valley highlights the potential for a multifaceted approach to remote sensing on the desert coast of South America and underscores the value of these well-established techniques for the rapid and detailed mapping of complex urban architecture. The Gallinazo Group (100 B.C.-A.D. 700) was an early city home to a population of between 10,000 and 14,400 people living in a network of agglutinated houses, plazas, public buildings, and alleyways. In 2008, detailed analysis of the site was undertaken, integrating traditional excavation techniques, soil coring, magnetometry, and ground-penetrating radar to gain a better understanding of the urban morphology of the site. The results of this fieldwork were extremely successful, with large areas of the urban layout being mapped in great detail. This article presents results from our survey, highlighting the potentials and limitations of each technique.

2002 ◽  
Vol 26 (2) ◽  
pp. 373-380 ◽  
Author(s):  
J. M. Ucha ◽  
M. Botelho ◽  
G. S. Vilas Boas ◽  
L. P. Ribeiro ◽  
P. S. Santana

Foram estudados nove perfis ao longo de uma toposseqüência sobre os sedimentos do Grupo Barreiras, na Fazenda Rio Negro, município de Entre Rios (BA), utilizando a prospecção eletromagnética por meio do Radar Penetrante no Solo - "Ground-penetrating radar - GPR", objetivando analisar a utilização dessa ferramenta na aquisição de informações sobre as feições que ocorrem no solo, mediante a comparação entre os radargramas obtidos e a descrição pedológica. O equipamento utilizado foi um Geophysical Survey System modelo GPR SR system-2, com antena de 80 MHz. A análise radargramétrica confirmou o aparecimento dos fragipãs e duripãs em profundidade, que ocorrem sempre acompanhados de um processo de transformação dos solos do tipo Latossolo Amarelo e Argissolo Amarelo em Espodossolo. Os padrões de reflexão mostram claramente os domínios dos solos argilosos e dos solos arenosos, com e sem a presença dos horizontes endurecidos.


2020 ◽  
Vol 12 (12) ◽  
pp. 2023 ◽  
Author(s):  
Pier Matteo Barone ◽  
Elizabeth Wueste ◽  
Richard Hodges

A collaboration between the American University of Rome, the Municipality of Giove, and Soprintendenza Archeologia, Belle Arti e Paesaggio dellʼUmbria has resulted in an academic project aimed at a preliminary evaluation of a particular area along the Tiber river that straddles the border between Umbria and Lazio. Archaeological prospection methods, such as Unmanned Aerial Vehicle (UAV)-based remote sensing, ground-penetrating radar (GPR), and photogrammetry, have made it possible to better study the landscape with respect to not only the changes the area has undergone recently, but also its evolution during the Roman and Medieval periods, while keeping the main communication route represented by the Tiber river as its fulcrum.


2020 ◽  
Vol 55 ◽  
pp. 41-63
Author(s):  
Marx Navarro Castillo ◽  
Hector Neff

This article is focused on the importance of remote sensing techniques for archaeological studies, specifically LiDAR, and geophysics techniques, such as ground penetrating radar (GPR). The use of LiDAR has become popular in the last ten years and its use in forested places has been very effective despite the low visibility. In the case of GPR, it is generally used in those places where evidence of structure remains can be found. However, in the sites identified by the Project Costa del Soconusco there are no buildings with these characteristics, but their usefulness for the identification of areas of ceramic production have been decisive for the development of our study. These techniques have provided important data that has allowed us to know more about the settlements located in the eastern region of Soconusco.


2021 ◽  
Author(s):  
Hai Liu ◽  
JianYing Lin ◽  
Xu Meng ◽  
Yanliang Du

<p><em>Abstract—</em>Metro traffic in subsurface tunnels is under a rapid development in many cities in the recent decades. However, the voids and other concealed defects inside and/or behind the tunnel lining pose critical threat to the safety of the operating metro tunnels. Ground penetrating radar (GPR) is a non-destructive geophysical technique by transmitting electromagnetic (EM) waves and receiving the reflected signals. GPR has proved its capability in the detection of the existence of tunnel structural defects and anomalies. However, the voids are still hard to be recognized in a GPR image due to the strong scattering clutter caused by the dense steel bars reinforced inside the concrete lining [1]. In this paper, we analyze the propagations of EM waves through reinforce concrete segments of shield tunnels by finite difference time domain (FDTD) simulations and model test.  Firstly, a series of simulations results we have done, indicates that the center frequency of GPR ranges from 400 MHz to 600 MHz has a good penetration through the densely reinforced concrete lining. And the distance between the antennas and the surface of shield tunnel segments should be less than 0.2 m to ensure a good coupling of incident electromagnetic energy into the concrete structure. Then, to image the geometric features of the void behind the segment, reverse-time migration method is applied to the simulated GPR B-scan profile, which presents higher resolution results than the results by using the traditional diffraction stack migration (Figure 1) [2]. Finally, the field experiment results prove that a commercial GPR system operating at a center frequency of 600 MHz do detect a void behind the shield tunnel (Figure 2). The reflection from the void, which starts from the back interface of the segments and lasts over 20 ns, are significantly different from the reflections from the rebars (Figure 3). In summary, GPR has potential in the detection of voids behind the shield tunnel segment. More simulations and field experiments will be performed in the future.</p><p>Keywords—ground penetrating radar (GPR); shield tunnel; voids; reverse time migration (RTM)</p><p>Acknowledgement—this work was supported by Shenzhen Science and Technology program (grant number:KQTD20180412181337494).</p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.5ecbddc6f70069664311161/sdaolpUECMynit/12UGE&app=m&a=0&c=eb6a5ae55b4b24b5585021db0e5ca760&ct=x&pn=gnp.elif&d=1" alt=""></p><p>Fig. 1 Numerical simulation of two segments of 2D shield tunnel. (a) numerical model, (b) simulated GPR B-scan profile, (c) migrated profile by using diffraction stack migration and (d) migrated profile by using reverse-time migration.</p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.659ecbe6f70069964311161/sdaolpUECMynit/12UGE&app=m&a=0&c=07531c033a4f74c3a8e3ac1f5f47316c&ct=x&pn=gnp.elif&d=1" alt=""></p><p>Fig. 2 One photo of the field experiment.</p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.d7c12807f70068274311161/sdaolpUECMynit/12UGE&app=m&a=0&c=dd5c073fd4c06a9fd77db502c1d017f2&ct=x&pn=gnp.elif&d=1" alt=""></p><p>Fig. 3 GPR reflections from a void behind the segment of a subway tunnel</p><p>References</p><p>[1]     H. Liu, H. Lu, J. Lin, F. Han, C. Liu, J. Cui, B. F. Spencer, “Penetration Properties of Ground Penetrating Radar Waves through Rebar Grids” , IEEE Geoscience and Remote Sensing Letters ( <strong>DOI:</strong> 10.1109/LGRS.2020.2995670)</p><p>[2]          H. Liu, Z. Long, F. Han, G. Fang, Q. H. Liu, “Frequency-Domain Reverse-Time Migration of Ground Penetrating Radar Based on Layered Medium Green's Functions”, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 11, no. 08, pp. 2957-2965, 2018.</p><p> </p>


2020 ◽  
Vol 90 (1) ◽  
pp. 131-149
Author(s):  
Natasha N. Cyples ◽  
Alessandro Ielpi ◽  
Randy W. Dirszowsky

ABSTRACT Braided rivers have accumulated a dominant fraction of the terrestrial sedimentary record, and yet their morphodynamics in proximal intermountain reaches are still not fully documented—a shortcoming that hampers a full understanding of sediment fluxes and stratigraphic preservation in proximal-basin tracts. Located in the eastern Canadian Cordillera near the continental divide, the Kicking Horse River is an iconic stream that has served as a model for proximal-braided rivers since the 1970s. Legacy work on the river was based solely on ground observations of small, in-channel bars; here we integrate field data at the scale of individual bars to the entire channel belt with time-lapse remote sensing and ground-penetrating-radar (GPR) imaging, in order to produce a more sophisticated morphodynamic model for the river. Cyclical discharge fluctuations related to both diurnal and seasonal variations in melt-water influx control the planform evolution and corresponding stratigraphic signature of trunk channels, intermittently active anabranch channels, and both bank-attached and mid-channel bars. Three-dimensional GPR fence diagrams of compound-bar complexes are built based on the identification of distinct radar facies related to: i) accretion and migration of unit bars, ii) both downstream and lateral outbuilding of bar-slip foresets; iii) buildup of bedload sheets, iv) channel avulsion, and v) accretion of mounded bars around logs or outsized clasts. Trends observed downstream-ward include decreases in gradient and grain size decreases, trunk-channel shrinkage, intensified avulsion (with increase in abundance for anabranch channels), and a shift from high-relief to low-relief bar topography. The integration of ground sedimentology, time-lapse remote sensing, and GPR imaging demonstrates that proximal-braided streams such as the Kicking Horse River can be critically compared to larger systems located farther away from their source uplands despite obvious scale differences.


Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2938
Author(s):  
Neil Linford ◽  
Russell MacKechnie-Guire ◽  
May Cassar

The aim of this trial project was to identify whether buried archaeological remains may have an influence on equine locomotion, through comparison with a non-invasive Ground Penetrating Radar (GPR) survey. This study was conducted at the world-renowned Burghley Horse Trials site, near Stamford, City of Peterborough, U.K. that has a diverse range of heritage assets throughout the wider park land centred on the Grade 1 listed Elizabethan Burghley House. The initial aim of the research was to first use geophysical survey to identify and characterise archaeological remains, and then to determine a suitable location to conduct an equine locomotion study. This trial was conducted with five event type horses with their gaits recorded through the use of three axis, wireless, Inertial Measurement Units, and high speed video capture. It was hoped that this study might indicate an association between the presence of well preserved archaeological remains and changes in the gait of the horses, similar to those shown by studies of dressage horses over different riding surfaces. The results from the equine locomotion study did demonstrate a correlation between the presence of surviving archaeological remains and the alteration in the horses’ gait and, although this is only a preliminary study, the results may well be of interest during the design and construction of equine event facilities. Geophysical survey could, for example, be considered during the design of new or alteration to existing equine courses to allow some mitigation in the location of the course with respect to any archaeological remains, or through the appropriate use of a protective artificial surface.


2021 ◽  
Author(s):  
Livia Lantini ◽  
Fabio Tosti ◽  
Luca Bianchini Ciampoli ◽  
Amir M. Alani

<p>Monitoring and protecting natural assets is increasingly important today, as aggressive pathogens are negatively impacting the trees' survival. In this regard, root systems are affected by fungal infections that cause roots’ rot and eventually lead to trees' death. Such disease can spread rapidly to the adjacent trees and affect larger areas. Since these decays generally do not display visible signs, early identification is the key to tree preservation.</p><p>Within this context, non-destructive testing (NDT) methods are becoming popular, being more versatile than destructive methods. Specifically, ground penetrating radar (GPR) is emerging as an accurate geophysical method for tree root mapping. Recent research has focused on implementing automated algorithms for 3D root mapping, improving root detection through advanced GPR signal processing and the estimation of tree roots' mass density [1]. Also, recent studies have proven that GPR is effective in mapping the root system's architecture of street trees [2].</p><p>The present research reports the preliminary results of an experimental study, conducted to investigate the feasibility of a novel tree root assessment methodology based on the analysis of GPR data both in time and frequency domain. To this end, data were processed using a short-time Fourier transform (STFT) approach [3], which allows the evaluation of how the frequency spectrum changes across the signal propagation time window. The suggested processing system may be implemented for expeditious analyses or on trees challenging to access, such as in urban environments, where more comprehensive survey methods are not applicable. The objectives of this study, therefore, are to investigate how different features (i.e., roots, layers) affect the time-frequency analysis of GPR data, and to identify recurring patterns in the results to set a coherent data processing methodology.</p><p>Results' interpretation has shown the viability of the presented approach in recognising the influence of different features on the analysis of GPR data as it changes over time. This also allowed the detection of recurring patterns in the analysed data, proving that this method is worthy of further investigations.</p><p>Acknowledgements<br>The authors would like to express their sincere thanks and gratitude to the following trusts, charities, organisations and individuals for their generosity in supporting this project: Lord Faringdon Charitable Trust, The Schroder Foundation, Cazenove Charitable Trust, Ernest Cook Trust, Sir Henry Keswick, Ian Bond, P. F. Charitable Trust, Prospect Investment Management Limited, The Adrian Swire Charitable Trust, The John Swire 1989 Charitable Trust, The Sackler Trust, The Tanlaw Foundation, and The Wyfold Charitable Trust.</p><p><br>References<br>[1]     Lantini, L., Tosti, F., Giannakis, I., Zou, L., Benedetto, A. and Alani, A. M., 2020. "An Enhanced Data Processing Framework for Mapping Tree Root Systems Using Ground Penetrating Radar," Remote Sensing 12(20), 3417.<br>[2]     Lantini, L., Alani, A., Giannakis, I., Benedetto, A. and Tosti, F., 2020. "Application of ground penetrating radar for mapping tree root system architecture and mass density of street trees," Advances in Transportation Studies (3), 51-62.<br>[3]     Bianchini Ciampoli, L., Calvi, A. and D'Amico, F., 2019. "Railway Ballast Monitoring by GPR: A Test Site Investigation," Remote Sensing 11(20), 238</p>


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