Surficial Features Research Articles

Neoichnology of Rhinella dorbignyi (Bufonidae) burrows: improving the recognition and interpretation of toad burrows

A neoichnological characterization of toad burrows from organic-rich soils is presented in order to establish key ichnological signatures for their recognition in the geological record. Dorbigny’s Toad (Rhinella dorbignyi) produces J-shaped burrows with a single elliptical opening resembling the ichnogenus Macanopsis. The burrow varies from 15 to 20 cm in length and has a constant diameter along the shaft, enlarged in the chamber. The shaft is elliptical with a diameter of 2.5-3.0 cm in the major axis and 1.0–1.5 cm in the minor axis. The chamber is semicircular, with a distinct floor, and an average diameter of 5 cm in the major axis. A thick (3–5 mm), compacted, smooth, and uniform inorganic lining made of soil covers the burrow throughout its length. Surficial features, such as horizontal and vertical millimeter-scale striations and ridges, occur in the burrow surface and are produced by keratinized granules and spikes on the skin of R. dorbignyi. Those surficial features are generated during the toad’s movements inside the burrow as well as anchoring during ambush predation behavior. The main distinct features observed on the burrow surface are well-developed circular pit impressions produced by the keratinized tubercles present in the toad’s ankles during climbing activity. These characteristics encompass useful ichnotaxobases for recognition and distinguishing toad burrows from J-shaped, Macanopsis-like burrows produced by other soil-dwelling animals. The burrow architecture of R. dorbignyi suggests that J-shaped burrows are efficient structures for ambush predatory behavior in terrestrial ecosystems, as observed in spiders and scorpions.

Chemical precursor-dependent dual effect of doping on the gas-sensing performance of metal oxide semiconducting materials

In this study, we report a chemical precursor-dependent dual effect of doping on the gas-sensing performance of metal oxide semiconducting materials. Our findings challenge the conventional notion that optimal doping consistently enhances gas-sensing properties. Acetate and nitrate salts were used as chemical precursors, lanthanum (La) was used as a dopant, and ZnO was used as a semiconducting material. All materials were synthesized under identical conditions by a two-step process involving dip coating and hydrothermal methods. Gas-sensing results demonstrated an improvement in the performance of the acetate-based doped film and a decline in that of the nitrate-based doped film compared to their respective pure counterparts. Among the produced sensors, 1 wt% La-doped ZnO sensor produced by the acetate precursor proved to be convenient for usages in real markets. It showed superior performance with a high response (62) at a relatively low operating temperature (150℃) towards 50 ppm of NH3 gas. The sensor also demonstrated exceptional baseline stability, high short-term and long-term consistency, good selectivity, and strong tolerance to humidity (up to 70 RH%) with slightly slow adsorption-desorption rates. The dual effect was discussed with respect to dopant- and precursor-induced variations in structural and surficial characteristics, revealed by XRD, Raman, FESEM, AFM, and XPS. The discussion delved deeper into the role of chemical precursors on nanostructure growth and, for the first time, illuminated a temperature-dependent complex gas-sensing principle governed by the detected p-n shift of the semiconductor type of the sensing elements, confirmed by Hall effect.

Insights on the dip of fault zones in Southern California from modeling of seismicity with anisotropic point processes

Accurate models of fault zone geometry are important for scientific and hazard applications. While seismicity can provide high-resolution point measurements of fault geometry, extrapolating these measurements to volumes may involve making strong assumptions. This is particularly problematic in distributed fault zones, which are commonly observed in immature faulting regions. In this study, we focus on characterizing the dip of fault zones in Southern California with the goal of improving fault models. We introduce a novel technique from spatial point process theory to quantify the orientation of persistent surficial features in seismicity, even when embedded in wide shear zones. The technique makes relatively mild assumptions about fault geometry and is formulated with the goal of determining the dip of a fault zone at depth. The method is applied to 11 prominent seismicity regions in Southern California. Overall, the results compare favorably with the geometry models provided by the SCEC Community Fault Model and other focused regional studies. More specifically, we find evidence that the Southern San Andreas and San Jacinto fault zones are both northeast dipping at seismogenic depths at the length scales of 1.0–4.0 km. In addition, we find more limited evidence for some depth dependent variations in dip that suggest a listric geometry. The developed technique can provide an independent source of information from seismicity to augment existing fault geometry models.

Magnetic Carbon Foam Adorned with Co/Fe Nanoneedles as an Efficient Activator of Oxone for Oxidative Environmental Remediation: Roles of Surficial and Chemical Enhancement

As heterogeneous catalysis is a practical method for activating Oxone, the immobilization of transition metals (e.g., Co, Fe) on carbonaceous supports is a promising platform. Thus, this study attempts to develop a carbon-supported metallic catalyst by growing Co/Fe on carbon foam (CF) via adopting melamine foam as a readily available template which could be transferred to nitrogen-doped CF with marcoporous structures. Specifically, a unique adornment of Co/Fe species on this CF is facilely fabricated through a complexation of Co/Fe with a plant extract, tannic acid, on melamine foam, followed by carbonization to produce nano-needle-like Co/Fe on N-doped CF, forming a magnetic CF (MCF). This resultant MCF exhibits a much higher surface area of 54.6 m2/g than CF (9.5 m2/g), and possesses a much larger specific capacitance of 9.7 F/g, than that of CF as 4.0 F/g. These superior features of MCF enable it to accelerate Oxone activation in order to degrade an emerging contaminant, bis(4-hydroxyphenyl)methanone (BHPM). Furthermore, MCF + Oxone exhibits a lower activation energy as 18.6 kJ/mol for BHPM elimination and retains its effectiveness in eliminating BHPM over multiple rounds. More importantly, the CF is also prepared and directly compared with the MCF to study the composition-structure-property relationship to provide valuable insights for further understanding of catalytic behaviors, surficial characteristics, and application of such a functional carbon material.

GIS based NRCS-CN modeling of rainfall-runoff in river Thamirabarani sub-basin, Southern India

River Thamirabarani sub-basin lies in the southern part of the Western Ghats in the Kanyakumari district of Tamil Nadu, India. The basin’s landforms are formed by swift surficial characteristics with undulated terrains composed of steep-sloped valleys, valley fills, and short-length streams with intensive flows that makes-up site-specific hydro-morphological characteristics. In this study, the GIS-based Natural Resource Conservation Service-Curve Number (NRCS-CN) model is used to assess rainfall-induced runoff by analyzing various hydrological parameters. The curve number (CN) is assigned to each hydrologic soil group (HSGs) based on the measurement of initial abstraction (Ia) and potential maximum retention (S) derived from soils, landuse/ land cover, antecedent soil moisture, etc. The resulting map shows the estimated runoff at the rate of 2.27 – 5.94 mm/m2/yr for the whole study area, whereas the higher runoff rate (4.83 – 5.94 mm/m2/yr) is noted in the upland range of the swift surficial terrains in the north and north-eastern parts that encompasses undulated structural hills, steep-sloped valleys, inselberg, and denudational hills, etc., whereas the work of swift surficial terrains and associated slope gradient of the landforms are considered to be higher runoff rate than the other parts. The moderate runoff rate (2.92 – 3.98 mm/m2/yr) is estimated in the middle parts of pediplains that consist of croplands, plantations, riverbanks, fallows, and built-up areas. Significantly, the lower runoff rate (<2.92 mm/m2/yr) sparsely occurred in the different landforms of the middle and southern parts that include pediplains, riverbanks, natural vegetative covers, valley-filled sediment deposits, etc. Overall results indicate that the higher runoff found over the swift surficial landforms in the north and north-eastern parts due to intensive flow through short-length stream orders. This study is mainly used for understanding hydro-morphological processes and their impacts on basin environments.

The Modern Nile Delta Continental Shelf, with an Evolving Record of Relict Deposits Displaced and Altered by Sediment Dynamics

The most extensive coverage of surficial sediment samples collected to date on Egypt’s Nile Delta coast and shelf is needed to better define sediment dispersal patterns across this setting’s rapidly eroding margin. Changes in time are now induced by River Nile sediment cutoff by dams, sea level rise, marked shelf subsidence, and regional climate changes, which have altered the amounts and components of sediments; these require replacement, along with the implementation of more effective coastal protection measures. Multiple computer-generated offshore maps depict the distributions and proportions of sand, silt, and mud; the mean grain size and standard deviation (sorting); heavy mineral concentrations; and carbonate content. Heavy mineral lobes at the coast and offshore identify former Nile branch sites. Channel lobes extending seaward resulted from their progradational phase and from the delta’s altered sedimentation from the early to late Holocene. The progressive deposition and erosion of these fossil fluvial lobes, and of two active Nile channels, selectively removed their quartz and less dense minerals, thus concentrating heavy minerals on the coast and inner shelf. The prolonged dispersal of original sediment effluence from relict and recent Nile tributaries induced variable depositional patterns on the present shelf. These coastal depocenters, along with extensive sand, silt, and mud from shelf sediments, were reworked further seaward and dispersed by bottom currents, thus masking most previous onshore-to-offshore transport patterns. The major surficial features document long-term responses to the diverse dispersal that influenced the shoreline to the outer shelf deposits from the Pleistocene to the present.

Deep Hydraulically‐Active Fractures in Sensitive Clay Deposits: Implications for Groundwater Flow and Slope Stability

AbstractLandslides in sensitive post‐glacial marine clays are one of the major geological hazards in Canada, Norway and Sweden. Current hydrogeological conceptual models used for slope stability analyses in these deposits consider simple groundwater flow conditions within a homogenous, isotropic, massive clay deposits, where fractures are surficial features that only exist within a 1–5 m‐thick weathered zone. This study uses cross‐correlation analysis on hydraulic head data from a large network of vibrating‐wire piezometers in clay deposits along the St. Lawrence River and in the Saguenay‐Lac St‐Jean Lowlands, in Quebec, Canada, to show that hydraulically‐active fractures are present to depths of up to 16 m at 4 (possibly 6) of the 7 locations studied. These findings suggest that current conceptual models have a high likelihood of misrepresenting local flow systems, and that further field and modeling work is needed to characterize the extent and influence of these fracture networks.

Rapid estimation of minimum depth-to-bedrock from lidar leveraging deep-learning-derived surficial material maps

Previously glaciated landscapes often share similar surficial characteristics, including large areas of exposed bedrock, blankets of till deposits, and alluvium-floored valleys. These materials play significant roles in geologic and hydrologic resources, geohazards, and landscape evolution; however, the vast extents of many previously glaciated landscapes have rendered comprehensive, detailed field mapping difficult. While recent advances in remote sensing have facilitated mapping of surficial materials and landforms, manual map creation has remained a time-intensive task.The development of convolutional neural networks (CNNs) for image classification has provided a new opportunity for rapid characterization of digital elevation models, thus enabling efficient mapping of surficial materials and landforms. We have developed a methodology that leverages existing geologic maps and high-resolution (1–3 m) lidar data to train a U-Net CNN to classify alluvium and exposed bedrock in previously glaciated regions. Coupled with U.S. Geological Survey-developed geomorphometry tools capable of approximating stream incision depths, these classifications can be used to estimate the minimum thicknesses of stream-proximal hillslope sediments in areas where streams have undergone minimal incision into bedrock.We validate this approach in the context of the Neversink River watershed, a subbasin of the Delaware River Basin and significant water source for New York City. Evaluation of deep learning model performance demonstrates substantial agreement with manually drawn maps of alluvium and exposed bedrock. Validation of the minimum sediment thickness map using borehole data and passive seismic measurements shows the greatest performance for shallow materials and decreased performance in deep sediments, as well as in areas where bedrock exposures were too small to be resolved by lidar. To resolve these issues and create more accurate surficial maps, we are training new CNNs with additional geologic data and exploring advanced approaches for estimating depths of stream incision.

Investigation of the physical-geographical characteristics of river delta with geophysical and satellite data. The case study of Pineios River, Greece

This paper presents the methodology of an applied geophysical and remote sensing research at river deltas for their subsurface and surface structure and its application in the deltaic plain of Pineios River (Thessaly, Greece). The scope is to primarily calculate the thickness of deltaic post alpine deposits, with the contribution of Transient Electromagnetic Method (TEM), but also identify the surficial characteristics (biotic/ abiotic) of the area with the appropriate combination of spectral bands and spectral indices. Regarding the remote sensing approach, some geomorphological features were outlined. This was managed from six false color composites of the area, produced by combining spectral bands and additional five false color composites by combining several spectral indices.•The results of the TEM method along with their statistical analysis provided important information regarding the spatial distribution and thickness of the lithological units along the deltaic plain.•The combination of spectral bands 8, 7, 6 seems to adumbrate the hydrographic network of the area and even detects possible changes in the inflow.•The combination of spectral indices MSAVI2, WV-BI, WV-WI was helpful enough to geomorphological mapping of the deltaic plain.

Electrical resistivity imaging of an enhanced aquifer recharge site.

Enhanced aquifer recharge (EAR) is defined as any engineered structure or enhanced natural feature designed to convey stormwater, surface water or wastewater directly into an aquifer (e.g. aquifer storage and recovery (ASR) wells) or into the vadose zone eventually percolating to an aquifer (e.g. spreading basins, dry well, etc.; USEPA 2021). Identifying the storage and flow capabilities of complex aquifers can improve the efficacy of many conceptual site models (CSM) for sites considered for ASR projects. In a karst setting, the EAR process may be able to take advantage of natural surficial features and the increased storage capacity of karst aquifers to improve recharge to groundwater. However, the suitability for an EAR project in a karst setting depends on the maturity of the karst and its preceding epikarst. The focus of flow within the epikarst causes enlargement of fractures and karst conduits. Thus, the storage and transmissivity within the karst vary greatly. Electrical resistivity imaging (ERI) is a well-known geophysical tool for mapping fractures and sinkholes, typical in karst settings. Locating enhanced water conveyance structures of a karst aquifer can improve the design and operation of an EAR site. This study investigated the hydraulic connection between shallow and deep groundwater using ERI to identify potential flow pathways and to improve our understanding of the storage mechanisms of the epikarst. The results presented in this paper validate the effectiveness of ERI in characterizing karst/epikarst and delineating soil, bedrock and local faults and fractures in the subsurface.

3D Meniscus‐Guided Evaporative Assembly for Rapid Template‐Free Synthesis of Highly Crystalline Perovskite Nanowire Arrays

AbstractLow‐dimensional nanostructures of halide perovskites have been receiving extensive research interest for their superior optical, electrical, and stability characteristics over their conventional bulk counterparts. In particular, the unique surficial characteristics of well‐defined 1D nanowires have shown high feasibility for high performance optoelectronic applications. The key aspect of endorsing this nanoscale form factor in practical applications lies in securing dimensional uniformity and controllability in large scales, which generally requires complicated lithographic procedures. In this work, a simple, rapid, and widely applicable strategy for the direct synthesis and printing of well‐aligned nanowire arrays on a large scale is demonstrated. By employing blade coating methods with sophisticatedly controlled stick‐slip motions, periodically resolved transverse 3D meniscus enables uniform directional growth of highly crystalline CsPbI3 nanowires without the need for templates. A systematic investigation of morphological evolutions with respect to kinetic processing variables is conducted, along with a comprehensive suite of structural and optical analyses for the synthesized nanowire arrays. A single nanowire photodetector is employed to demonstrate the superiority and applicability of the fabrication strategy. Finally, a 2D image recognition is demonstrated by using an array of photodetectors fabricated via a fast (&lt;2 min) direct printing of nanowire arrays on wafers.

Utilization of CO2 as a physical blowing agent for foaming of high temperature sulfone polymers

The present work adopts the one-step batch foaming technique to develop microcellular foams from polysulfone (PSU) and polyethersulfone (PES) using supercritical carbon dioxide (CO2) as a physical blowing agent. The results illustrates that the high temperature polymers can successfully generate highly uniform cellular structures with CO2, exhibiting cell densities in the order of 1010 cells/cm3 but limited volume expansion ratios of up to 4 times. The cell densities of both systems, PSU/CO2 and PES/CO2, were observed to be highly affected by the foaming pressure, showing significant enhancement of over 5 orders of magnitude with an increase in pressure from 3.4 to 13.8 MPa. On the other hand, the expansion ratio showed a strong dependence on the foaming temperature. Especially, the foams produced at pressures below 13.8 MPa exhibited a unique double peak behavior consisting of two maximum expansion ratios obtained at two different temperatures. In the temperature range of the first expansion peak, nanostructures were observed on the cell walls of the foams. The surficial features appeared in the form of a nanofibril network and gradually disappeared as the temperature approached the region of the second peak. Based on the observation, the unique double peak behavior may be correlated to the presence of the nanostructures. The work also encompassed measurement of CO2 solubility and high pressure thermal analysis of the two polymers, which were incorporated in the discussion of the distinctive foaming behavior.

Heap leach pad mapping with drone-based hyperspectral remote sensing at the Safford Copper Mine, Arizona

Mapping the distribution of minerals, pipes, ponded lixiviant, and other surficial features on heap leach pads is a continuing challenge for hydrometallurgy operations, maintenance, and design. Recently, commercial drone technology has enabled remote sensing techniques to be deployed for some leach pad mapping and surveying applications, but applications to hydrometallurgical operations are still emerging. This project tested one potential mapping technology, drone-based hyperspectral remote sensing, for mapping leach pads, using the Safford mine as a test site.The results show that hyperspectral remote sensing can acquire information about mineral distribution, piping system, and lixiviant ponding. The main minerals detected on the leach pads are kaolinite, muscovite, and gypsum, although the detection of gypsum is probably due to the widespread sulfate precipitating from agglomerating acid and lixiviant. The path of the stacker loading rocks, lixiviant ponding, and drip lines can also be seen in the spectral images. Chlorite and biotite, long-term acid consumers, were not detected in the results, but are on the leach pads. Best practices for hyperspectral remote sensing in mapping leach pads include: building a reference library from ground-truth samples, using high spatial resolution for mapping piping systems and low spatial resolution for mapping minerals, scanning leach pads in sunshine, and scanning before leaching starts.

Applying laboratory methods for durability assessment of vitrified material to archaeological samples

Laboratory testing used to assess the long-term chemical durability of nuclear waste forms may not be applicable to disposal because the accelerated conditions may not represent disposal conditions. To address this, we examine the corrosion of vitrified archeological materials excavated from the near surface of a ~1500-year old Iron Age Swedish hillfort, Broborg, as an analog for the disposal of vitrified nuclear waste. We compare characterized site samples with corrosion characteristics generated by standard laboratory durability test methods including the product consistency test (PCT), the vapor hydration test (VHT), and the EPA Method 1313 test. Results show that the surficial layer of the Broborg samples resulting from VHT displays some similarities to the morphology of the surficial layer formed over longer timescales in the environment. This work provides improved understanding of long-term glass corrosion behavior in terms of the thickness, morphology, and chemistry of the surficial features that are formed.

"Raspberry" Hierarchical Topographic Features Regulate Human Mesenchymal Stem Cell Adhesion and Differentiation via Enhanced Mechanosensing.

An understanding of cellular mechanoresponses to well-defined synthetic topographic features is crucial for the fundamental research and biomedical applications of stem cells. Structured biointerfaces, in particular the ones with nanometer and/or micrometer surficial features, have drawn more attention in the past few decades. However, it is still difficult to integrate nanostructures and microstructures onto the synthesized biointerfaces to mimic the hierarchical architecture of the native extracellular matrix (ECM). Herein, a series of "raspberry"-like hierarchical surfaces with well-defined nanofeatures and tunable nano/microfeatures have been achieved via a catecholic polymer coating technique. Cellular responses to these hierarchical interfaces were systemically studied, indicating that the nanofeatures on the raspberry surfaces significantly enhanced the mechanosensing of human mesenchymal stem cells (hMSCs) to interfacial physical cues. Cell mechanotransduction was further investigated by analyzing focal adhesion assembling, cytoskeleton organization, cell nuclear mechanics, and transcriptional activity. The results suggest that nanosize surficial features could increase cellular mechanosensing to environment physical cues. The mechanotransduction and cell fate specification were greatly enhanced by the ECM mimicking nano/microhierarchical biointerfaces but the features should be in an optimized size.

Application of the Comparison of Multibeam Echo-Sound Records to the Study of Stability of a Toxic Waste Stockpile Located on the Margin of a Tidal System: Tinto Estuary, Huelva, SW Spain

For more than 40 years, the industrial complex which developed near Huelva (in SW Spain) produced a huge amount of phosphogypsum as a waste product of manufacturing fertilizers. This waste was stockpiled in a stack 25 m high, covering 1200 ha of what was once a salt marsh. The weight of that enormous amount of waste produced active subsidence in the underlying sediment. Part of the sediment was injected into the marginal areas, where the load pressure is minor, causing significant vertical movement in the floor of the estuarine channel. This manuscript describes several surficial features using multibeam echosound. A crest formed by cones and a bulge area could be interpreted as injection structures. The evolution of the topographic position of the floor was also analyzed by comparing different records of the estuarine bed in the margins of the stockpile. The data in this work document the changes in the dynamics of the estuary in relation to these vertical movements. These changes in dynamicsled to erosion and deposition in various areas of the bed.

Plasma electrolytic oxidation of cold spray kinetically metallized CNT-Al coating on AZ91-Mg alloy: Evaluation of mechanical and surficial characteristics

The cold-spray kinetically metallized (CS) carbon nanotube-aluminum (CNT-Al) and pure Al coatings were treated using plasma electrolytic oxidation (PEO) process to obtain CNT-Al+PEO and Al+PEO duplex coatings on AZ91 Mg alloy, respectively. The phase composition, microstructure, mechanical properties, wear and corrosion resistance of the PEO ceramic coatings were studied. The results showed that the PEO ceramic coating was mainly composed of α-Al2O3 and γ-Al2O3, moreover, the small amount of CNT was also retained during the PEO process. The mechanical properties and wear resistance of the PEO ceramic coatings were significantly improved compared to the respective CS coatings. In particular, the hardness and elastic modulus of the PEO-CNT coating reached 13.9 GPa and 185.4 GPa, which were 21.0% and 23.4% higher than the respective CS coating. Moreover, the wear rate of the PEO-CNT coating was only 4.83 × 10−5 mm3/N·m with a relatively low coefficient of friction of 0.65, which were 59.8% and 15.6% lower than the corresponding CS coating. The corrosion current density of the PEO-treated CNT-Al coating was 3.734 × 10−6A/cm2, which was similar to the untreated CS coating. In short, the PEO treatment greatly improves the mechanical properties and wear resistance of the CS CNT-Al coating.

Rhizosphere: A fascinating paleovegetational and paleoclimatic new intermediary in the Quaternary fluvio-lacustrine set-up of the Purna alluvial basin, central India

The rhizosphere, a fascinating vegetational and climatic negotiator, has been discovered and being reported from widespread Quaternary fluvio-lacustrine sediments of the Purna alluvial basin, central India. These organo-sedimentary structures representing diversified morphologies i.e., rounded to sub-rounded, spherical to sub-spherical, small to large surfaced, calcretized bodies of 7–20 cm diameter, are confined principally within the constraints of paleosol horizons belonging to the Early Pleistocene period, uncovered at the lower reaches of the Purna river course. These structures, developed in the lower niches/specialities around plant roots, are formed due to the mutual exercises of soil and fungi. Based on morphological criteria and surficial feature demonstrations, four distinctive morphotypes of the same have been categorized i.e., i) concentric, ii) rimmed, iii) concentric disrupted, and iv) nodular or mottled. The initial two sorts are conceived to be formed by fungi associated with living trees, whereas, last two are created by contagious exercise with rotting plant roots. A model portrayed shows their development in open spaces having a close relationship of plant roots belonging to both forests (C3) and grassland (C4) categories with microbial communities underneath the ground. Consequently, the spaces made by plant roots and microbial community are occupied by the calcium carbonate leached out from the encompassing soils during arid to semi-arid climate.

Comparison of Near-Fault Displacement Interpretations from Field and Aerial Data for the M 6.5 and 7.1 Ridgecrest Earthquake Sequence Ruptures

ABSTRACT Coseismic surface fault displacement presents a serious potential hazard for structures and for lifeline infrastructure. Distributed lifeline infrastructure tends to cover large distances and may cross faults in multiple locations, especially in active tectonic regions like California. However, fault displacement measurements for engineering applications are quite sparse, rendering the development of predictive models extremely difficult and fraught with large uncertainties. Detailed fault surface rupture mapping products exist for a few documented cases, but they may not capture the full width of ground deformations that are likely to impact distributed infrastructure. The 2019 Ridgecrest earthquake sequence presented an ideal opportunity to collect data and evaluate the ability of different techniques to capture coseismic deformations on and near the fault ruptures. Both the M 6.5 and 7.1 events ruptured the surface in sparsely populated desert areas where little vegetation is present to obscure surficial features. Two study areas (~400 m × 500 m each) around the surface ruptures from the two events were selected. Teams of researchers were deployed and coordinated to gather data in three ways: field measurements and photographs, imagery from small uninhabited aerial systems, and imagery from airborne light detection and ranging. Each of these techniques requires different amounts of resources in terms of cost, labor, and time associated with the data collection, processing, and interpretation efforts. This article presents the data collection methods used for the two study areas, and qualitative and quantitative comparisons of the results interpretations. While all three techniques capture the key features that are important for displacement design of distributed infrastructure, the use of remote sensing methods in combination with field measurements presents an advantage over the use of any single technique.

Estimation of total groundwater reserves and delineation of weathered/fault zones for aquifer potential: A case study from the Federal District of Brazil

Abstract In the Federal District of Brazil, groundwater extraction is challenged by fractured aquifers with difficulty in identification of hydraulic traps and significant uncertainty in the estimation of recharge potential. This study aims to optimize the demarcation of new locations of tubular wells by the aid of geophysical investigation. In the first stage of this study, the total exploitable amount of groundwater were calculated from the information of the physical environment and the existing wells. Second, electrical resistivity tomography (ERT) method was carried out on the selected sites – based on their surficial characteristics. The possible hydraulic traps (where groundwater might exist) were identified from the inversion of the resistivity measured by the dipole–dipole array and from the delineation of the resultant conducting zones (including the weathered rocks and fractures). Using this approach, we predicted the position and number of tubular wells required and ranked them according to their potential productivity. The study provides a promising framework for investigating groundwater in fractured aquifers.