Precise orbit determination of near-Earth asteroids (NEAs) provides a critical foundation for exploration missions. Considering that cislunar space is a critical domain for future human space activities and the unique positional advantage of the Earth-Moon L1 point, space-based optical observations from the Earth-Moon L1 point's orbit hold significant potential for improving NEAs orbit determination accuracy. Coordinating such space-based observations with ground-based optical observations is expected to provide essential technical support for high-precision orbit determination. This study focused on two representative NEAs, 2016HO3 and Apophis. We validated the effectiveness of existing optical observations by processing 328 latest ground-based data of 2016HO3. The calculated position true error of the initial state vector was 31.932 km, with a position uncertainty of 24.293 km. The Yarkovsky effect parameter A2 of 2016HO3 was solved to be (-1.257 +/- 0.343)& times;10-13 AU/day2. Furthermore, we conducted ground-space based orbit determination simulation analyses for 2016HO3 and Apophis to quantitatively evaluate the potential advantages of combining optical observations from the Earth-Moon L1 point's orbit with ground-based observations in enhancing orbit determination accuracy. The results indicate that within the observation accuracy considered in this study, space-based optical observations reduce orbit determination uncertainty by up to 20% for 2016HO3 and 62% for Apophis. The inclusion of space-based observations reduces the position true error by up to 50% for 2016HO3 and 83% for Apophis, and it can enhance the signal-to-noise ratio (SNR) of A2. Additionally, we found that the orbit error of the L1 point probe has a notable influence on the position true error of NEAs, reaching several kilometers for 2016HO3 and several hundred meters for Apophis.

Flash floods are among the most destructive hazards in Mediterranean mountain regions, often disrupting roads and socio-economic connectivity. On 29 February 2024, an extreme pluvial flash flood in northeastern Algeria overtopped the 427.5 m Oued Endja Bridge on National Road 105 by about 0.5 m, halting mobility in Mila. This study presents a reproducible framework combining HEC-HMS event-based hydrological modeling and HEC-RAS 1D hydraulic simulations, validated with field surveys and Sentinel-2 imagery. Using 105.7 mm of rainfall at Beni Haroun station and a curve number of 83.5, the model estimated a peak discharge of about 2629 m³/s and an overtopping depth of 0.44 m, consistent with observations. Hazard metrics, including depth, velocity, and unit stream power, informed operational thresholds and early-warning triggers. Channel excavation and vegetation management lowered simulated flood levels by about 5.7 m, demonstrating practical measures to reduce overtopping risk and improve flood resilience under a changing climate.

This paper presents a comparative study of three deep learning (DL) architectures for one-dimensional magnetotelluric (MT) data inversion: long short-term memory (LSTM), gated recurrent unit (GRU), and Informer models. We developed a comprehensive framework for generating realistic synthetic MT data, training the models, and evaluating their performance through multiple quantitative metrics. Our synthetic dataset comprised 100,000 samples with 25 periods spanning 10−3 to 103 seconds, created using statistical parameters derived from real MT data. Each model was trained on apparent resistivity and phase responses to recover subsurface resistivity profiles. The results show that the recurrent neural network architectures (LSTM and GRU) slightly outperform the attention-based Informer model, with the LSTM achieving the best performance (MSE of 0.06455 Ωm2, R2 of 0.45234). Despite their differing architectures, all the models successfully captured the major subsurface resistivity contrasts. When applied to real MT data from the UAE, the tested models showed promising results in terms of reconstructing subsurface structures. Overall, this study demonstrates the viability of DL approaches for MT inversion, with potential applications in efficient field-based subsurface imaging.

The groundwater distribution in southern Egypt is primarily governed by the region’s inherited rift-related tectonic framework. We integrated aeromagnetic data with available hydrogeochemical and seismic data to investigate structural controls on groundwater accumulation in El-Gallaba Plain along the western margin of the Kom Ombo Basin. The magnetic data were processed using edge-detection filters and source-parameter imaging to estimate the depth of the basement rock. Moreover, three-dimensional geophysical inversion of magnetic data was performed using the iteratively re-weighted least-squares algorithm to map the basin geometry. The results of magnetic data interpretation delineated a NW-SE major trend and minor NE-SW-trending, fault-bounded depressions extending to depths of 2.5–3.0 km, interpreted as sediment-filled or altered-basement fractured basins favorable for groundwater accumulation. Uplifted basement blocks define structural highs that act as hydraulic barriers, compartmentalizing the area’s aquifer system. The interpreted magnetic structures were correlated with previously published land-surface temperature and hydrochemical data, revealing a spatial alignment among deep structural depressions, low-temperature corridors, and zones of fresher, isotopically depleted groundwater. This correlation confirms that reactivated Pan-African and Cenozoic faults control the vertical permeability and groundwater connectivity of the Nubian Sandstone Aquifer. Overall, this study highlights the effectiveness of three-dimensional inversion, along with edge-detection and depth-estimation filters applied to magnetic data to resolve subsurface architecture and interpret groundwater potential in arid, tectonically complex regions.

Gravity‐Derived Moho Depth of Egypt: Insights from Lithospheric-Scale Gravity Inversion and Comparison with Global Crustal ModelsMohammad Shehata1,2, Hakim Saibi11Geosciences Department, College of Science, United Arab Emirates University, 15551, Al-Ain, United Arab Emirates2Department of Geology, Faculty of Science, Port Said University, Port Said 42522, Egypt Reliable constraints on Moho depth are fundamental for understanding lithospheric structure and tectonic evolution, yet estimates across Egypt and northeastern Africa remain uneven in coverage and resolution. Seismic constraints are restricted to discrete locations, while global crustal models mainly capture long-wavelength features and may not resolve crustal thickness contrasts across different tectonic domains. Here we present a country-scale Moho depth model for Egypt derived from GOCE satellite gravity, providing continuous regional coverage for evaluating tectonically controlled crustal thickness variations.Bouguer gravity anomalies were computed from GOCE satellite gravity data, complemented where appropriate by terrestrial observations, and corrected for topography, bathymetry, and sedimentary cover. Moho geometry was estimated using frequency-domain Parker–Oldenburg iterative inversion incorporating laterally variable crust–mantle density contrasts derived from the CRUST1.0 model, allowing spatial variations in crustal composition and thickness to be explicitly accounted for (Shehata and Mizunaga, 2022). The resulting Moho model reveals systematic crustal thickness variations that closely correspond to Egypt’s tectonic architecture, with shallow Moho depths (~18–22 km) beneath extensional domains associated with Red Sea rifting, intermediate depths (~28–34 km) in transitional zones such as the Nile Delta and Sinai, and thick crust (>40–43 km) across the Western Desert and southern Egypt. Sharp lateral Moho gradients delineate boundaries between these regimes, indicating localized strain accommodation during rift development. Comparison with CRUST1.0 (Laske et al., 2013), GEMMA (Reguzzoni et al., 2013), and the seismic-based Moho compilation of Tugume et al., 2013) shows overall agreement at long wavelengths, while localized deviations occur in rifted and transitional regions due to differences in data resolution and methodological sensitivity. These results demonstrate that tectonic regime exerts a first-order control on Moho depth beneath Egypt and highlight the value of GOCE-based gravity inversion for improving lithospheric characterization in regions of limited seismic coverage.ReferencesLaske, G., Masters, G., Ma, Z., Pasyanos, M., 2013. Update on CRUST1. 0—A 1-degree global model of Earth’s crust, in: Geophysical Research Abstracts. p. 2658.Reguzzoni, M., Sampietro, D., Sansò, F., 2013. Global Moho from the combination of the CRUST2. 0 model and GOCE data. Geophys. J. Int. 195, 222–237.Shehata, M.A., Mizunaga, H., 2022. Moho depth and tectonic implications of the western United States: insights from gravity data interpretation. Geosci. Lett. 9, 23.Tugume, F., Nyblade, A.A., Julia, J., Van der Meijde, M., 2013. Crustal shear wave velocity structure and thickness for Archean and Proterozoic terranes in Africa and Arabia from modeling receiver functions, surface wave dispersion, and satellite gravity data. Tectonophysics 609, 250–266.

Impact-induced geological structures are commonly distributed around lunar multi-ring basins, typically appearing as ring and radial topographic features in imagery. While some of these structures are exposed at the lunar surface, others remain buried and require detection. Gravity data provides critical insights into the accurate identification of these features, advancing our understanding of impact cratering mechanics and the lunar interior structure. In this study, we proposed a novel method to enhance the identification of ring and radial geological structures around multi-ring basins. We introduced the Strike Response Factor (SRF) as the characteristic signal, which is calculated from horizontal gravity gradient components in a rotated reference coordinate system. Based on the SRF, we utilized the K-means clustering algorithm to search for potential impact-induced geological structures in maximum principal horizontal second derivative maps. We applied this method to the forward-modeled data and the observed data of the lunar Orientale Basin. Validation results confirm the effective identification of ring and radial impact-induced features. Moreover, the method reveals previously undiscovered ring features through its enhanced sensitivity to subtle gravity signals. The gravity gradient method effectively detects weak gravitational signals from small-scale impact structures, including potential ring faults, dikes, radial fractures, and ejecta ridges. This approach offers a valuable tool for enhancing our understanding of impact processes and the internal architecture of lunar multi-ring basins.

This study aims to assess the effectiveness of using airborne geophysical (magnetic and radiation) data to map radioactive-favorable zones in Wadi Rod Ghurabat area, South Eastern Desert, Egypt. Airborne gamma-ray spectrometry contour maps displayed marked variations in total-count, eU, eTh, and K parameters with ranges of 1.2–11.6 μR/h, 0.3–6.9 ppm, 0.3–20.8 ppm, and 0.1–3.2

The Nubian Sandstone Aquifer System (NSAS) represents the principal groundwater resource in Egypt's Western Desert, sustaining agricultural and socio-economic development in arid environments. Increasing groundwater abstraction in the El Farafra Oasis requires a robust understanding of aquifer heterogeneity and hydraulic behavior to support sustainable management. This study integrates borehole geophysical logs, lithological data, and hydrogeological measurements from 37 groundwater wells to characterize the petrophysical and hydraulic properties of the NSAS. The effective porosity, shale volume, formation factor, permeability, hydraulic conductivity, transmissivity, and storativity were estimated using physics-based petrophysical models calibrated against available pumping-test data. A high-resolution 3D geostatistical workflow was applied to map the spatial variability of aquifer properties while respecting well control and stratigraphic boundaries. The results reveal pronounced lateral and vertical heterogeneity within the NSAS controlled by depositional facies architecture, shale intercalations, and structural features. Formation factor values inversely correlated with shale volume, indicating high-quality reservoir zones in the northeast. Effective porosity values (∼0.17–0.34) indicate good to excellent aquifer quality, particularly in the northeast, while the permeability (k > 1000 mD) and hydraulic conductivity (K > 9 m/d) typify highly productive sandstone aquifers. Transmissivity commonly exceeds 2000 m2/d and storativity ranges from 10−4 to 10−3, consistent with confined to semi-confined NSAS conditions reported in previous studies, indicating that El Farafra Oasis provides a representative analog for regional groundwater behavior. The proposed workflow represents a transferable methodology for upscaling well-based petrophysical information into regional groundwater flow models, supporting sustainable groundwater management and long-term planning across the broader NSAS.

The Orientale Basin is the youngest and best-preserved multi-ring impact basin on the Moon. It is approximately 930 km in diameter and comprises three concentric rings-the Cordillera, Inner Rook and Outer Rook rings. We used Gravity Recovery and Interior Laboratory (GRAIL) mission gravity data (GRGM1200B, truncated to degree 660) to invert the 3-D density structure associated with the basin's mascon and ring-related crustal anomalies. To separate longer and shorter wavelength signals, we performed inversions using (1) spherical harmonic degrees 2-660 to characterize the basin's deep structure and (2) degrees 60-660 to highlight crustal-scale heterogeneity. The inversion with degree and order of 2-660 resolves a basin-wide central positive density anomaly beneath the inner depression, extending from a depth of similar to 16-80 km, corresponding to uplifted mantle. This anomaly persists below the crust-mantle boundary; however, its deep continuation should be interpreted cautiously because it may partially reflect vertical smearing in the gravity inversion. Nonetheless, the spatial association of this anomaly with a mascon rooted in the upper mantle is compatible with impact-driven uplift of dense material from depth, followed by post-impact thermal evolution and relaxation processes. The inversion with degree and order of 60-660 indicates alternating positive and negative density anomalies associated with the ring system. Prominent ring-parallel positive anomalies occur along the Outer Rook Ring and Cordillera Ring, extending to similar to 30-35 km depth and exhibiting a density contrast of similar to 60-200 kg m(-3). The geometry and lateral continuity of these anomalies across multiple rings support an interpretation of ring-controlled crustal heterogeneity, consistent with either intrusion and structurally focused modification along ring-related discontinuities or impact-generated fracturing that provided pathways for magma ascent. The results of this study provide quantitative constraints on the depth, magnitude and spatial distribution of density anomalies associated with the Orientale mascon and ring system, thereby improving the subsurface framework for regional geological interpretation and supporting future lunar landing-site geophysical investigations and in situ sampling. Based on the inferred crustal density architecture, we propose that future geophysical sampling efforts should prioritize the Outer Rook Ring and Cordillera Ring, where the observed ring-parallel anomalies may provide insights into crustal modification processes and the composition of the lunar interior.

The Moon's Atlas crater, centered at approximately 47 degrees N, 44 degrees E and with a diameter of similar to 87 km, is a typical floorfractured crater (FFC) in the northeastern lunar highlands. The presence of a fractured crater floor, asymmetric uplift, and dark lava deposits within this impact crater may indicate the combined effects of multi-stage processes accompanying the impact event and subsequent magmatic intrusion. Despite the fact that the surface geological information is available from remote sensing studies, the link between subsurface processes and the effects of the multiple impacts that shaped those surface manifestations is still elusive. To bridge the limitations of subsurface structures detected in remote sensing and morphological studies and to provide a preliminary subsurface structural interpretation linked to past geological processes, we performed 3D density inversion based on Bouguer gravity data (60-600 degree band-pass-filtered) from the Gravity Recovery and Interior Laboratory (GRAIL) 1200-degree gravity model. We employed multidirectional regularization and depth-weighted linear model constraints in a spherical coordinate system to reduce the non-uniqueness of the inversion results. The modeled densities reveal a west-to-east-decreasing density gradient (highly consistent with the observed nonaxisymmetric surface uplift) and two discrete independent high-density anomalies outside the Atlas crater. The former reflects the multi-phase magmatic intrusion history and impact-influenced evolution of the Atlas crater (forming the main magma intrusion system), while the latter are interpreted as a regional magmatic dike and a small-scale impact melt zone, unrelated to Atlas's formation. These findings provide direct evidence for the genetic mechanism (coupling between impact modification and magmatic activity) of lunar highland FFCs. The shallow high-density anomaly, which corresponds to high-Ti basalt, may contain Fe-Ti-rich minerals, as also observed from remote sensing studies, making it a potential high-priority target for future in-situ resource utilization.

Subsurface cavities in Jebel Hafeet, Al-Ain City, United Arab Emirates, pose geohazard risks to infrastructure due to subsidence and ground instability. This study employed electrical resistivity tomography (ERT) and gravity methods to locate and characterize these cavities and assess their associated risk. The ERT survey was conducted using a pole-dipole array configuration along eight lines, with intermediate-resistivity (> 45 Ohm.m) anomalies indicating cavities at depths between 1 m and 16 m below ground level and low-resistivity (< 45 Ohm.m) zones suggesting water-saturated or clay-rich deposits. The gravity survey was observed at 28 stations, with the calculated Bouguer gravity values ranging from 97 to 103 mGal. The 3D inversion of the Bouguer gravity data revealed low-density anomalies interpreted as cavities, which were spatially consistent with the locations of high-resistivity zones in the ERT data. The 3D gravity inversion models revealed low-density zones, indicating cavities at depths of a few meters to 20 m below ground level. Integrating ERT and gravity methods improved cavity detection in the study area, indicating a strong correlation between low-density and intermediate resistivity features. This research contributes to an improved geological and geohazard understanding of Jebel Hafeet, aiding sustainable urban planning, infrastructure safety, and risk mitigation in Al-Ain City.

The gravity field of small celestial bodies, such as asteroids and comets, plays a critical role in revealing their internal structure and enhancing precise spacecraft navigation. Previous gravity field models face the following difficulties: (i) computational inefficiency for detailed shapes, (ii) divergence near irregular surfaces, (iii) limited capability to model heterogeneous bodies, and (iv) lack of physical feasibility for learning-based models. To overcome these limitations, we propose the neural potential field framework that represents the gravity potential using a coordinate-based neural network with periodic activation functions. By leveraging Poisson's equation, a body's internal density distribution can be derived directly from the learned potential field. Forward modeling experiments on the comet 67P/Churyumov-Gerasimenko and asteroid Itokawa demonstrate the model's high accuracy. Inverse modeling applied to the asteroid Bennu, using real mission data, reveals an underdense core and equatorial bulge, consistent with prior studies. Compared to traditional models, the neural potential field model achieves the best accuracy (0.2-0.3 percent relative error) and efficiency (5-7 ms per 10,000 evaluation points), while avoiding divergence issues as observed in the spherical harmonics model. Meanwhile, its compact memory footprint (0.4 megabytes) is approximately 160 times smaller than the high-fidelity polyhedron model. The model's dual capability in gravity field forward modeling and density inversion can effectively support trajectory planning, autonomous navigation, and scientific analysis for missions targeting asteroids or comets.

Abstract In the Abu Dhabi Emirate, near Madinat Zayed and Liwa, studies have identified high geothermal gradients and high‐heat‐flow areas. Assessing the geothermal potential in this region requires a detailed mapping of subsurface geological formations and their thermal properties. This study employed broadband magnetotelluric (BBMT) measurements to map the geological formations, focusing on the basement rock structures linked to the high‐heat‐flow anomaly observed in the area. The three‐dimensional inversion of BBMT data revealed a high‐resistivity anomaly at 10 km depth beneath a highly conductive Quaternary sediment layer in the high‐heat‐flow area. This high‐resistivity layer is interpreted as basement rocks. To interpret the MT model, gravity, magnetic, seismic, and heat flow data were used, and a two‐dimensional gravity‐magnetic model was constructed along the BBMT profile. The high‐heat‐flow anomaly in the study area is interpreted as due to the existence of highly magnetized basement rocks.

Lacus Somniorum, the largest lacus-type volcanic plain on the Moon, lies outside major impact basins and provides a key test case for understanding nonbasin mare formation. Here we combine remote sensing observations and gravity-based geophysical analyses to investigate its surface morphology, composition, subsurface structure, and volcanic chronology. We identify three major episodes of volcanism between similar to 3.7 and similar to 3.1 Ga. Gravity inversions reveal deep-seated high-density mafic bodies, consistent with basaltic underplating, and supporting the possibility of dike intrusions associated with mantle diapirism. The youngest eruptions record diminished magma supply and more evolved compositions, indicating a progressive decline in magmatic activity. These results suggest that multiphase diapirism-driven magmatism played a central role in shaping Lacus Somniorum and may represent a common mechanism for mare volcanism outside large impact basins, refining current models of lunar magmatic evolution.

Accurate pre-encounter asteroid ephemerides are needed for planning short-duration spacecraft flybys. We present updated orbit solutions for three Emirates Mission to the Asteroid Belt flyby targets, (23871) Ousha, (59980) Moza, and (88055) Ghaf, with planned encounters in 2032 and 2033. We combined Minor Planet Center astrometry with Gaia Focused Product Release observations and estimated each orbit using iterative weighted least squares. The combined solutions give statistically consistent post-fit residuals, with Gaia along-scan residuals centered close to zero and normalized scatter near unity. Relative to MPC-only solutions, adding Gaia FPR reduced reference-epoch formal state uncertainties for all three targets. Propagation to the nominal flyby epochs gives MPC + Gaia 1 sigma position uncertainties of 5.1 km for Ousha, 6.6 km for Moza, and 9.9 km for Ghaf, dominated by the along-track direction. The corresponding geocentric sky-plane 1 sigma angular uncertainties are 3.6, 2.3, and 4.2 mas. Estimated Yarkovsky accelerations are statistically insignificant for all three asteroids. These results show that Gaia FPR astrometry substantially improves the pre-encounter ephemerides of the EMA flyby targets.

Algeria lies in the southwestern segment of the Tethyan tectonic domain and is enrich of hydrocarbon. However, the tectonic deformation process and dynamic mechanisms governing its sedimentary record remain inadequately understood. This study analyzes the structural characteristics of Algeria's Phanerozoic sedimentary record based on available data, reconstructs regional tectonic evolution by using balanced cross-sections, and the dynamic mechanisms of basin evolution based on plate tectonic processes were discussed as well. The key findings are as follows: (1) Algeria's structural domains are latitudinally divided into the TellianAtlas, the Saharan Atlas and the Saharan Platform, with the latter exhibiting a east-west zoning. The distribution of basins and uplifts on the northern margin is basically consistent with the Atlas Orogenic Belt. (2) On the basis of structural and stratigraphic evolution, the Saharan Platform can be categorized into four development zones: western, southern, eastern, and northern margins. (3) The western region features NW-SE-trending Paleozoic cratonic depression basins; the southern region comprises N-S-trending Paleozoic cratonic depression basins; the eastern includes Paleozoic cratonic depression basins superimposed by Mesozoic depression basins; and the northern margin consists of Paleozoic cratonic basins superimposed by Mesozoic depression basins that evolved into Cenozoic foreland basins. The Saharan Atlas compresses Mesozoic rift basins overlain by Cenozoic foreland basins. Tellian Atlas fold and inversion resulting from the Miocene accretion of the Kabylie microcontinents onto the North African margin. (4) The primary tectonic deformation ages young progressively from south to north and from west to east. (5) Tectonic deformation intensifies with proximity to plate boundaries: The Hercynian compression was stronger in the west than in the east, Mesozoic rifting was more pronounced in the east than in the west, and the Cenozoic Alpine movements induced stronger deformation in the north than in the south. The far-field effects of above-mentioned tectonic movements warrant further investigations. (6) The structural domains evolution comprises five stages: (i) post-Pan-African orogenic extension to initial Cambrian rifting; (ii) rifting and drifting along Gondwana's northern margin leading to Paleozoic subsidence; (iii) Pangea assembly and Hercynian basin reworking; (iv) opening of the Atlantic and Neo-Tethys oceans resulting in Mesozoic rifting; and (v) closure of the Neo-Tethys Ocean and Cenozoic foreland basin development. (7) Overall, Algeria's Phanerozoic sedimentary basins formed on a nearly N-S-trending alternating basin-and-uplift framework following a post-Pan-African E-W extension and collapse. They subsequently underwent NW-SE compression during the Hercynian orogeny, NE-SW extension during the Mesozoic, and NW-SE compression during the Cenozoic Alpine movements, resulting in the present tectonic framework.

This study evaluates the applicability and effectiveness of ceramic membrane filtration (CMPWT) for treating lake water and treated wastewater samples in Al-Ain, United Arab Emirates (UAE). Water samples were collected from Mubazzarah Lake (geothermal water), Airport Lake, Ain Al Fayda, and Zakher Lake (treated municipal wastewater). All the samples exhibited high salinity and organic content, with total organic carbon (TOC) values reaching up to 25 mg/L in Zakher Lake, a value 10 times higher than that of typical natural lakes. The CMPWT system achieved up to 50 % TOC reduction and complete removal of suspended solids, improving water clarity. However, the transmembrane pressure (TMP) increased rapidly, especially for Zakher Lake samples (up to 90 kPa within 10 min), indicating severe fouling. Coagulation with 100 mg/L polyaluminium chloride improved the TMP stability but did not fully eliminate fouling. These findings demonstrate that ceramic membrane filtration, when combined with robust pre-treatment methods such as biological filtration and ozonation, can provide a sustainable solution for water reclamation. This study’s results support the development of recreational and non-potable water reuse systems in arid settings such as the UAE.

Studies in the Abu Dhabi Emirate, near Madinat Zayed and Liwa, identified high geothermal gradients and high-heat-flow areas. This study employed broadband magnetotelluric (BBMT) measurements to map the geological formations, focusing on the basement rock structures linked to the high-heat-flow anomaly observed in the area. The three-dimensional inversion of BBMT data revealed a high-resistivity anomaly at 10 km depth beneath a highly conductive Quaternary sediment layer in the high-heat-flow area interpreted as basement rocks. To interpret the MT model, gravity, magnetic, seismic, and heat flow data were used, and a two-dimensional gravity-magnetic model was constructed along the BBMT profile. The high-heat-flow anomaly in the study area is interpreted as due to the existence of highly magnetized basement rocks.