Coherent electromagnetic losses by scattering from volume inhomogeneities

Roth, L. E.; Elachi, C.

doi:10.1109/tap.1975.1141170

Cited by 55 publications

(38 citation statements)

References 6 publications

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“…The new versions of SRTM DEMs [30,31] are the result of interpolation efforts of the unedited SRTM DEM version 2 (~90 m). These SRTM data has been chosen because the depth of penetrating near surface paleodrainages is up to 0.5 m [16][17][18]. Near surface features (palaeolake and paleodrainages) appear dark in SRTM data.…”

Section: Data Sources and Pre-processingmentioning

confidence: 99%

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Hydromorphological Mapping and Analysis for Characterizing Darfur Paleolake, NW Sudan Using Remote Sensing and GIS

Elmahdy¹

2012

IJG

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The north-western part of Sudan, which is the driest region on earth has revealed newly surface and near surface paleodrainage network underneath sand sheets indicating the possibilities for economic groundwater reservoirs. Advanced Space-born Thermal Radiometer (ASTER), the Shuttle Radar Topography Mission (SRTM ~90 m) DEMs and Quickbird images corroborate the presence of surface and near surface paleodrainage network. Bivariate quadratic surfaces with moving window size of 3 × 3 were fitted to the SRTM DEM. The second derivative surface curvature was calculated to reveal landform classes that may receive most of fossil water. The results showed that the new unnamed depression which recharges by a longitudinal paleodrainage network may receive vast amount of groundwater during humid phases. The results demonstrate that the D8 and curvature algorithms are very efficient tools for revealing and characterizing hydrological elements in arid and semi-arid regions and they provide information for hydrological exploration in remote deserts over large scale prior to geophysical survey.

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Section: Data Sources and Pre-processingmentioning

confidence: 99%

“…The depth of penetration near surface paleodrainages using C-band radar is up to 0.5 m [16,17]. This is because of the scarcity of lakes (water bodies), rainfall, vegetation cover, low topography and low soil moisture content.…”

Section: Introductionmentioning

confidence: 99%

Hydromorphological Mapping and Analysis for Characterizing Darfur Paleolake, NW Sudan Using Remote Sensing and GIS

Elmahdy¹

2012

IJG

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“…The penetration of the waves reaches to 0.5 m in the extremely dry sand (Roth & Elachi 1975). This study demonstrated a valuable geological information source that can be in geological and geotectonic applications.…”

Section: Discussionmentioning

confidence: 76%

“…The new version of SRTM DEMs (version3 http://srtm.csi.cgiar.org/ Index.asp) is the result of interpolation efforts of the un-edited SRTM DEM version 2 (»90 m). We used SRTM DEM due to the ability of active sensor waves to penetrate the extremely dry sand sheets and reveal the fault zones at 50 cm in the subsurface (Elmahdy et al 2011;Elmahdy & Mohamed 2013a), and invariability of gravity data to bring out will define the signatures of rock dislocation (Roth & Elachi 1975).…”

Section: Data and Pre-processingmentioning

confidence: 99%

Mapping of tecto-lineaments and investigate their association with earthquakes in Egypt: a hybrid approach using remote sensing data

Elmahdy

Mohamed

2015

Geomatics, Natural Hazards and Risk

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This study integrates quantitative methods to detect surface and near-surface geological linear structures from digital elevation model. A set of altitude, slope and shaded relief maps was enhanced by applying Sobel filter with 10% threshold and percentile stretch to detect geological fractures and their displacements over regional scale. Topographic fabric grain algorithm, which classifies point lines into the ridge/valley and quantifies the degree to which all the ridges and valleys are aligned in the same direction, was used to auto-detect lineaments. About 1300 linear features were computed and their orientations were statistically analysed using rose diagrams. The enhanced morphometric maps successfully visualized fault zones and their displacements and detected the regional fault zones cutting across the entire Egypt. Their trends were found to be in the NEÀSW, NNEÀSSW, NWÀSE, NNWÀSSE, NÀS, EÀW and WNWÀESE directions. The results obtained using the integrated methods were compared with those in geological and seismic maps of Egypt and showed strong agreement in several places. This proposed method may be useful for mapping concealed geological structures, where geophysical surveying is difficult and geological information not available.

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“…Over the last four decades, the growing number and quality of space imagers has strongly contributed to the identification of possible impact structures (e.g., [9,11]) which usually appear as distinct ring anomalies marking the original Earth surface. Unlike optical sensors, which can only image the surface of the desert, long-wave microwave sensors can unveil sand-hidden subsurface features [12]. In particular, radar images at C and L bands have successfully revealed sand-buried paleoriver courses and lake basins in several parts of the Great Sahara [13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Rimaal: A Sand Buried Structure of Possible Impact Origin in the Sahara: Optical and Radar Remote Sensing Investigation

Ghoneim

2018

Remote Sensing

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This work communicates the discovery of a sandy buried 10.5 km diameter near-circular structure in the eastern part of the Great Sahara in North Africa. Rimaal, meaning "sand" in Arabic, is given as the name for this structure since it is largely concealed beneath the Sahara Aeolian sand. Remote sensing image fusion and transformation of multispectral data (from Landsat-8) and synthetic aperture radar (from Sentinel-1 and ALOS PALSAR), of dual wavelengths (C and L-bands) and multi-polarization (HV, VV, HH, and HV), were adopted in this work. The optical and microwave hybrid imagery enabled the combining of surface spectral properties and subsurface roughness information for better understanding of the Rimaal structure. The long wavelength of the radar, in particular, enabled the penetration of desert sands and the revealing of the proposed structure. The structure exhibits a clear outer rim with traces of concentric faults, an annular flat basin and an inner ring surrounding remnants of a highly eroded central peak. Radar imagery clearly shows the interior wall of the structure is incised with radial pattern gullies that originate at or near the crater periphery, implying a much steeper rim wall in the past. In addition, data reveals a circumferential of a paleoriver course that flows along a curved path parallel to the crater's western margin indicating the plausible presence of a concentric ring graben related to the inferred structure. The defined crater boundary is coincident with a shallow semi-circular-like basin in the SRTM elevation data. The structure portrays considerable modifications by extensive long-term Aeolian and fluvial erosion. Residing in the Cretaceous Nubian Sandstone formation suggests an old age of ≤65 Ma for the structure. If proven to be of an impact origin, the Rimaal structure could help in understanding the early evolution of the landscape of the Eastern Sahara and holds promise for hosting economically valuable ore deposits and hydrocarbon resources in the region.

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Coherent electromagnetic losses by scattering from volume inhomogeneities

Abstract: z6 n! 32 (n + 2) ! 384 (n + 3) ! (A-6) can be written as iei(ko-k)(L-x'+ct') I2 z exP (kok). (Lx' + c t ') a,(K,x',t').

Cited by 55 publications

References 6 publications

Hydromorphological Mapping and Analysis for Characterizing Darfur Paleolake, NW Sudan Using Remote Sensing and GIS

Hydromorphological Mapping and Analysis for Characterizing Darfur Paleolake, NW Sudan Using Remote Sensing and GIS

Mapping of tecto-lineaments and investigate their association with earthquakes in Egypt: a hybrid approach using remote sensing data

Rimaal: A Sand Buried Structure of Possible Impact Origin in the Sahara: Optical and Radar Remote Sensing Investigation

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