Distribution and causes of intricate saline - sodic soil patterns in an upland South Australian hillslope

Soil Research ◽  
2009 ◽  
Vol 47 (3) ◽  
pp. 328 ◽  
Author(s):  
M. Thomas ◽  
R. W. Fitzpatrick ◽  
G. S. Heinson
Keyword(s):  
Soil Survey ◽  
Terrain Analysis ◽  
Topographic Wetness Index ◽  
Sodic Soil ◽  
Near Surface ◽  
Landscape Processes ◽  
Surface Water Flow ◽  
Geophysical Surveys ◽  
Soil Landscape ◽  
D Loop

We describe a soil–landscape investigation conducted in a South Australian upland hillslope (128 ha) to understand the distribution and causes of saline–sodic soil patterns using convenient, ground-based geophysical surveys of the hillslope. These surveys included: (i) EM31 for deep (~6 m) apparent electrical conductivity (ECa) patterns, (ii) EM38 for shallow (>1.5 m) ECa patterns, and (iii) Bartington MS2-D loop sensor for surface volume magnetic susceptibility (κ) patterns. From these surveys we inferred hillslope distributions of: (i) deep (~6 m) concentrations of salinity associated with deep groundwater systems and deposits of magnetic gravels (dominated by maghemite and hematite) (EM31 sensor); (ii) shallow (<1.5 m) soil salinity (EM38 sensor); and (iii) preservation of pedogenic magnetic materials (e.g. maghemite and hematite) (MS2-D loop sensor). We also describe terrain analysis to locate near-surface hydropedological patterns using topographic wetness index. When combined in 3D geographic information system, strong visual matches were identified between patterns in: (i) geophysical surveys, (ii) terrain, and (iii) soil survey data, thus allowing integrated interpretations of soil–landscape pedogenic processes to be made on a whole-of-landscape basis. Such mechanistic interpretations of soil–landscape processes reveal and map intricate saline and sodic soil–regolith patterns and groundwater and fresh surface water flow paths that were not revealed during a previous traditional soil survey.

Shallow Magnetic Induction Measurements for Delineating Near-Surface Hot Groundwater Sources in Alaskan Geothermal Areas

1983 ◽  
Vol 105 (2) ◽  
pp. 156-161 ◽  
Author(s):  
T. E. Osterkamp ◽  
K. Kawasaki ◽  
J. P. Gosink
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Induction ◽  
Hot Springs ◽  
Measured Temperature ◽  
Conductivity Data ◽  
Induction Method ◽  
Near Surface ◽  
Saline Groundwater ◽  
Geophysical Surveys ◽  
Conductivity Anomalies

Variations in the electrical conductivity of a soil and water system with temperature and salt concentration suggest that a soil containing hot and/or saline groundwater may be expected to have a higher conductivity compared to a cooler and/or less saline system. Temperature and conductivity surveys were carried out at Pilgrim Springs, on the Seward Peninsula, and at Chena Hot Springs, near Fairbanks, to test the use of a magnetic induction method (which measures electrical conductivity) for delineating near-surface hot groundwater sources in geothermal areas surrounded by permafrost. Comparison of the temperature data and conductivity data from these surveys demonstrates that the conductivity anomalies, as measured by the magnetic induction method, can be used to define the precise location of hot groundwater sources in these geothermal areas with the higher temperatures correlating with higher values of conductivity. Magnetic induction measurements of conductivity can also be used to define the lateral extent of the thawed geothermal areas (used for calculating the stored energy) in permafrost terrain. The utility of these magnetic induction measurements of conductivity for reconnaissance geophysical surveys of geothermal areas is that a much greater density of data can be obtained in a shorter time in comparison with shallow temperature measurements. In addition, it is simpler, cheaper and easier (physically) to obtain the data. While conductivity anomalies can result from other than hot and/or saline groundwater, these conductivity data, when coupled with a few measured temperature profiles and groundwater samples, should result in reliable reconnaissance level geophysical surveys in Alaskan geothermal areas.

scholarly journals Computing water flow through complex landscapes – Part 2: Finding hierarchies in depressions and morphological segmentations

2020 ◽  
Vol 8 (2) ◽  
pp. 431-445
Author(s):  
Richard Barnes ◽  
Kerry L. Callaghan ◽  
Andrew D. Wickert
Keyword(s):  
Water Flow ◽  
Hydrological Modeling ◽  
Dynamic Models ◽  
Terrain Analysis ◽  
Flow Paths ◽  
Topographic Complexity ◽  
Morphological Segmentation ◽  
Surface Water Flow ◽  
Digital Elevation ◽  
Flow Through

Abstract. Depressions – inwardly draining regions of digital elevation models – present difficulties for terrain analysis and hydrological modeling. Analogous “depressions” also arise in image processing and morphological segmentation, where they may represent noise, features of interest, or both. Here we provide a new data structure – the depression hierarchy – that captures the full topologic and topographic complexity of depressions in a region. We treat depressions as networks in a way that is analogous to surface-water flow paths, in which individual sub-depressions merge together to form meta-depressions in a process that continues until they begin to drain externally. This hierarchy can be used to selectively fill or breach depressions or to accelerate dynamic models of hydrological flow. Complete, well-commented, open-source code and correctness tests are available on GitHub and Zenodo.

Surveying Batavia’s Graveyard: Geophysical controlled experiments and subsurface imaging of archaeological sites on an Indian Ocean coral island

Geophysics ◽  
2017 ◽  
Vol 82 (4) ◽  
pp. B147-B163 ◽  
Author(s):  
Jeffrey Shragge ◽  
David Lumley ◽  
Nader Issa ◽  
Tom Hoskin ◽  
Alistair Paterson ◽  
...  
Keyword(s):  
Sea Water ◽  
Controlled Experiments ◽  
Near Surface ◽  
Survey Techniques ◽  
Geophysical Surveys ◽  
Archaeological Materials ◽  
Coral Island ◽  
Water Saturated ◽  
Ground Penetrating ◽  
Geophysical Anomalies

We conducted geophysical surveys on Beacon Island in the Houtman Abrolhos archipelago offshore Western Australia, to investigate areas of archaeological interest related to the 1629 Batavia shipwreck, mutiny, and massacre. We used three complementary near-surface geophysical survey techniques (total magnetic intensity, electromagnetic induction mapping, and ground-penetrating radar) to identify anomalous target zones for archaeological excavation. Interpreting near-surface geophysical anomalies is often complex and nonunique, although it can be significantly improved by achieving a better understanding of site-specific factors including background conditions, natural variability, detectability limits, and the geophysical response to, and spatial resolution of, buried targets. These factors were not well-understood for Beacon Island nor indeed for the Australian coastal environment. We have evaluated the results of controlled experiments in which we bury known targets at representative depths and analyze the geophysical responses in terms of an ability to detect and resolve targets from natural background variability. The maximum depth of detectability of calibration targets on Beacon Island is limited to approximately 0.5 m due to significant variations in background physical properties between a thin ([Formula: see text]) and highly unconsolidated dry sand, shell, and coral layer of variable thickness overlying a sea-water-saturated sandy half-space. Our controlled measurements have implications for calibrating and quantifying the interpretation of geophysical anomalies in areas of archaeological interest, particularly in coastal and sandy-coral island environments. Our geophysical analyzes contributed to the discovery of archaeological materials and five historical burials associated with the 1629 Batavia shipwreck.

Flow and Radionuclide Transport From Rock to Surface Systems: Characterization and Modelling of Potential Repository Sites in Sweden

2007 ◽  
Author(s):  
Kent Werner ◽  
Emma Bosson ◽  
Sten Berglund
Keyword(s):  
Surface Water ◽  
Groundwater Flow ◽  
Water Flow ◽  
Exit Point ◽  
Flow Paths ◽  
Near Surface ◽  
Mike She ◽  
Mike 11 ◽  
Surface Water Flow ◽  
Safety Assessments

The safety assessments of potential geological repositories for spent nuclear fuel in Sweden are supported by modelling of groundwater flow in rock, to predict locations (exit points) where radionuclides from the deep repository may enter land, surface waters and associated ecosystems above the rock. This modelling includes detailed rock descriptions, but simplifies the upper part of the flow domain, including representations of meteorological processes and interactions with hydrological objects at the surface. Using the Laxemar candidate site as example, this paper investigates some potentially important consequences of these simplifications. Specifically, it compares particle tracking results obtained by a deep-rock groundwater flow model (CONNECTFLOW) and by MIKE SHE-MIKE 11, which contains detailed descriptions of near-surface/surface water flow. Overall, the models predict similar exit point patterns, occurring as clusters along streams in valleys, at a lake, and in sea bays. However, on a detailed level there are some prediction differences, which may be of importance for biosphere-focused safety assessments. CONNECTFLOW essentially predicts flow paths through the repository that follow fractures and deformation zones, outcropping in valleys. In comparison, MIKE SHE-MIKE 11 provides more detailed information on near-surface water flow paths, including the associated exit points and inputs to assessments of radionuclide retention.

High resolution GPR investigations employing single and multichannel systems in the Necropolis of Monte Abatone, Cerveteri (Roma, Italy).

2020 ◽  
Author(s):  
Salvatore Piro ◽  
Bruna Malandruccolo
Keyword(s):  
Ground Penetrating Radar ◽  
Landscape Archaeology ◽  
Dual Frequency ◽  
Near Surface ◽  
Complete Mapping ◽  
Geophysical Surveys ◽  
Near Surface Geophysics ◽  
Anomalous Bodies ◽  
And Migration ◽  
Ground Penetrating

&lt;p&gt;The Monte Abatone Necorpolis is one of the main important necropolis of Cerveteri, located 60 km north of Rome (Latium, Italy). In this area, several tombs have been discovered and excavated from the 1800, though still many remain hidden underneath the subsurface.&lt;/p&gt;&lt;p&gt;In the last two years, geophysical surveys have been carried out to investigate the unexplored portions of the ancient Etruscan Necropolis, to provide a complete mapping of the position of the tombs. Ground Penetrating Radar and the Magnetometric methods have been used during 2018 to investigate few parts of the Necropolis. During 2019 (July and September) GPR system SIR 3000 (GSSI), equipped with a 400 MHz antenna with constant offset, SIR4000 (GSSI) equipped with a dual frequency antenna with 300/800 MHz and the 3D Radar Geoscope multichannel stepped frequency system were employed to survey 5 hectares where the presence of tombs was hypothesized from previous archaeological studies.&lt;/p&gt;&lt;p&gt;All the GPR profiles were processed with GPR-SLICE v7.0 Ground Penetrating Radar Imaging Software (Goodman 2017). The basic radargram signal processing steps included: post processing pulse regaining; DC drift removal; data resampling; band pass filtering; background filter and migration. With the aim of obtaining a planimetric vision of all possible anomalous bodies, the time-slice representation technique was applied using all processed profiles showing anomalous sources up to a depth of about 2.5 m.&lt;/p&gt;&lt;p&gt;The preliminary obtained results clearly show the presence of a network of strong circular features, linked with the buried structural elements of the searched tombs.&lt;/p&gt;&lt;p&gt;Together with archaeologists, these anomalies, have been interpreted to have a better understanding of the archaeological definition of these features and to enhance the knowledge of the necropolis layout and mapping; after the geophysical surveys, excavations have been conducted, which brought to light few of the investigated structures.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Campana S., Piro S., 2009. Seeing the Unseen. Geophysics and Landscape Archaeology. Campana &amp; Piro Editors. CRC Press, Taylor &amp; Francis Group. Oxon UK, ISBN 978-0-415-44721-8.&lt;/p&gt;&lt;p&gt;Goodman, D., Piro, S., 2013. GPR Remote sensing in Archaeology, Springer: Berlin.&lt;/p&gt;&lt;p&gt;Piro S., Papale E., Zamuner D., Kuculdemirci M., 2018. Multimethodological approach to investigate urban and suburban archaeological sites. In &amp;#8220;Innovation in Near Surface Geophysics. Instrumentation, application and data processing methods.&amp;#8221;, Persico R., Piro S., Linford N., Ed.s. pp. 461 &amp;#8211; 504, ISBN: 978-0-12-812429-1, pp.1-505, Elsevier.&lt;/p&gt;

Looking high and low: comparing a UAV-based and a ground-based methodology for the detection of vineyard terrace failures

2020 ◽  
Author(s):  
Anton Pijl ◽  
Edoardo Quarella ◽  
Teun A. Vogel ◽  
Vincenzo D'Agostino ◽  
Paolo Tarolli
Keyword(s):  
Remote Sensing ◽  
Surface Water ◽  
Water Concentration ◽  
Field Measurements ◽  
Time Domain Reflectometry ◽  
Terrain Analysis ◽  
Topographic Wetness Index ◽  
Cross Sectional ◽  
Spatially Distributed ◽  
Dry Conditions

&lt;p&gt;Agricultural terraces are known to be related to complex hillslope hydrology, characterized by surface and sub-surface water flows. Locally high fluxes or accumulation of water can be responsible for terrace wall failures, such as collapse and piping. There is a need for both scientific research and applied sustainable viticulture to better understand these processes. A key challenge is to find a suitable balance between highly integrated but local field measurements, and a more approximate but widespread approach such as remote sensing.&amp;#160;In this study, two distinctive methodologies were applied in order to locate and explain terrace wall failure observed in a north-Italian vineyard: a field-based vs. a remote sensing approach. The field-based approach was based on spatially distributed measurements of topsoil soil moisture content using Time Domain Reflectometry (TDR) instrument. This survey revealed high relative soil water concentration at the damaged terraces, in both wet and dry conditions. Furthermore, a unique cross-sectional saturation profile was found above the damaged walls, with the highest values found near the edges. The remote sensing approach was based on a photogrammetric survey and subsequent high-resolution digital terrain analysis and modeling using the Topographic Wetness Index (TWI) and SIMulated Water Erosion model (SIMWE). Results showed how the formation of surface water flow patterns explains the location of damaged walls.&amp;#160;These findings show both the opportunities and limitations of the two approaches. Field measurements provided more conclusive information about the location of walls at risk (high predictive potential), but this approach is relatively labour-intensive (low upscaling potential) as compared to a remote sensing approach. The latter can be a powerful tool for acquiring fully distributed estimations of wall failure over larger non-instrumented areas.&lt;/p&gt;

scholarly journals Combining Resistivity and Aeromagnetic Geophysical Surveys for Groundwater Exploration in the Maghnia Plain of Algeria

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Djamel Boubaya
Keyword(s):  
Groundwater Potential ◽  
Groundwater Exploration ◽  
Magnetic Data ◽  
Geoelectric Section ◽  
Resistive Layer ◽  
Near Surface ◽  
Groundwater Aquifer ◽  
Geophysical Surveys ◽  
Schlumberger Sounding ◽  
Topsoil Layer

The Maghnia plain in western Algeria is filled by Plio-Quaternary and Miocene sediments that rest unconformably on a basement of Jurassic rocks. Electrical sounding (VES), magnetic data, well information, and hydrogeological data have been used to explore for groundwater potential in the Maghnia plain. The interpretation of Schlumberger sounding data was first calibrated with the lithology of available nearby wells. Four geoelectrical layers were identified within the study area. They are a thin near surface topsoil layer with variable resistivities, a moderate resistive aquifer (15–30 ohm-m), a resistive aquifer (40–70 ohm-m), and a conductive clay layer (1–10 ohm-m). Near Sidi Mbarek, the geoelectric section is reduced to three layers: a topsoil layer, a conductive layer corresponding to the Miocene marls, and a deep resistive layer that correlates with the Oxfordian sandstones. The interpretation of VES data and the enhancement techniques of magnetic data enabled the identification of a number of unmapped faults that occur near recharge zones close to adjacent mountains. This study enabled us to study the extension of the known Plio-Quaternary aquifer of the Maghnia plain and to explore the possible existence of a second deep groundwater aquifer in Oxfordian sandstones.

Geostatistical simulation for geophysical applications—Part II: Geophysical modeling

Geophysics ◽  
1990 ◽  
Vol 55 (11) ◽  
pp. 1441-1446 ◽  
Author(s):  
P. N. Shive ◽  
T. Lowry ◽  
D. H. Easley ◽  
L. E. Borgman
Keyword(s):  
Physical Properties ◽  
Seismic Velocity ◽  
Seismic Refraction ◽  
Three Dimensional ◽  
Companion Paper ◽  
Geostatistical Simulation ◽  
Near Surface ◽  
Geophysical Modeling ◽  
Karst Environment ◽  
Geophysical Surveys

A companion paper (this issue) describes a method for producing three‐dimensional simulations of physical properties for different geologic situations. Here we create a simulation for a particular case, which is a near‐surface (<80 ft deep) description of a karst environment. We simulate seismic velocity, density, resistivity, and the dielectric constant for this situation. We then conduct (in the computer) hypothetical geophysical surveys at the surface of the model. These surveys are seismic refraction, microgravity, dc resistivity, and ground‐probing radar. Physical properties appropriate for cavities are then entered in the model. Repeating the geophysical surveys over the model with cavities provides a convenient method of evaluating their potential for cavity detection. Anomalies produced by normal variations in physical properties may simulate or obscure anomalies from target features. More data about the correlation of physical properties, particularly in the horizontal directions, will be required to evaluate this problem properly.

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