Snow cover is a critical component of the hydrological cycle in mountain regions. Monitoring mountain snow cover has become increasingly urgent due to climate warming. To analyse its seasonal dynamics, manual snow-depth measurements with a snow stake at the Skalnaté Pleso Observatory (1778 m a.s.l.) were complemented by time-lapse trail-camera observations of the surrounding area. Analyses of time-lapse images over four winter seasons (2021/22–2024/25) revealed pronounced interannual variability in snow cover dynamics and showed that the camera reliably captured snow conditions during both continuous-snow and snow-poor winters. In the 2024/25 season, average snow depth was exceptionally low (9.5 cm), while average snow cover remained around 50%, suggesting far-reaching consequences for environmental systems. A clear non-linear relationship was found between snow depth and camera-derived snow cover, with rapid increases in areal cover at low snow depths and saturation at approximately 30–40 cm (R2 = 0.76). Time-lapse imagery, after image alignment, mask application, and automatic image classification, proved to be a robust and cost-effective complement to point-based measurements.
The current work presents a probabilistic seismic hazard assessment (PSHA) for engineering bedrock conditions (Vs30} = 760 m/s) across the Jizan region of southwestern Saudi Arabia. For this purpose, we compiled a homogenised earthquake catalogue covering 827–2022 CE, including historical and instrumental records from multiple authoritative sources. All magnitude types are converted to moment magnitude (Mw) using orthogonal regression. After declustering and completeness analysis, we defined eight area-source zones to represent the tectonic variations of the Red Sea rift, the Gulf of Aden, the Arabian Shield, and adjacent Yemeni crustal domains. Seismicity in each zone was characterised with a doubly truncated Gutenberg–Richter model. The maximum magnitudes were estimated using the Kijko–Sellevoll–Bayes approach. To account for epistemic uncertainty in ground-motion attenuation, we employed a logic tree with four GMPEs weighted equally: Abrahamson et al. (2014), Akkar et al. (2014), Chiou and Youngs (2014), and Zhao et al. (2006). Resulting bedrock hazard maps show a clear north–south gradient across Jizan. For a 475-year return period (≈ 10% in 50 years), PGA rises from ∼0.03 g in northern districts to ∼0.06 g near the Yemeni border; for a 2,475-year return period (≈ 2% in 50 years), PGA increases from ∼0.06 g to ∼0.13 g. A site-specific Uniform Hazard Spectrum for the Baish development area indicates a peak spectral acceleration of ∼85 cm/s2 at T ≈ 0.2 s for the 475-year return period and ∼165 cm/s2 for the 2,475-year return period. These results indicate that seismic demand in Jizan is controlled primarily by extensional deformation of the southern Red Sea and active crustal deformation in western Yemen. The study provides a robust bedrock-hazard baseline suitable for engineering design and urban planning in the Baish district.
The differentiations of potential fields play an important role in their interpretations, as they are included in many of the enhanced transformations and edge detectors (Analytical Signal Amplitude, Tilt derivatives, Total Differentiation and others). However, the evaluation of horizontal and vertical differentiation is an unstable process. This instability was partially solved in the past by, e.g. Tikhonov regularisation for the first-order differentiations. Here, we present and compare several regularised stabilisations of higher-orders of differentiations. The methods are tested on synthetic and real data sets, where results indicate the usefulness of the presented method in the potential fields' processing and interpretation. Good properties of higher order regularised derivatives are demonstrated on selected edge-detection operator: in this case, on the modified balanced horizontal gradient operator.
This study presents a comparative geoelectrical survey utilising Wenner, Wenner-Schlumberger, and Dipole-Dipole arrays to evaluate the subsurface of the Shakrook anticline in the Erbil Governorate. 3D electrical resistivity tomography (ERT) images are obtained using IRIS Syscal Junior with 72 electrodes and three arrays operating concurrently. To assess the engineering behaviour at the site, a 2D parallel array of seven profiles measuring 2D is established. The data inversion is performed using ZondRes3D software to generate a 3D resistivity model. The Wenner array emphasis on vertical resistivity differences facilitated the identification of three separate electro-lithological units in the region: a shallow conductive soil layer (5 – 30 Ω·m) with variable thickness (2.5 – 12.5 m), marly limestone (30 – 136 Ω·m) with (10 – 23 m) thickness, and deeper, competent dolomitic limestone (136 – 398 Ω·m) from the depth 10 m to the depth of the block. The Wenner-Schlumberger array facilitated a balance between vertical and lateral sensitivity, hence enhancing the resolution of fracture zones. The enhanced lateral resolution of the Dipole-Dipole array delineated the precise limits of narrower conductive anomalies, notably a prominent vertical low-resistivity corridor between x = 95 – 125 m, consistently characterised as a fault-controlled karst or seepage conduit. Geotechnical interpretation indicates that high-resistivity benches at depths of 13 – 36 m serve as optimal foundation layers for supporting substantial loads, but conductive seams are associated with weak, damp, or clay-rich zones that pose risks of settlement, seepage, and instability. The integration of all three arrays demonstrates that no one array can fully resolve complex carbonate environments; rather, their collective use establishes a versatile framework for site characterisation, foundation planning, and hazard assessment in the absence of boreholes. The results illustrate the importance of multi-array ERT for geotechnical design in the structurally complex carbonate terrains of northern Iraq.
The gold mining sector necessitates the adoption of efficient, fast and contemporary technologies for gold exploration that accurately describe the structural setup, shear zones, faults, and other related geological features associated with mineralisation. In this work, a survey utilising land magnetics, induced polarisation (IP), transient electromagnetic (TEM), and electrical resistivity tomography (ERT) was utilised to map and primarily characterise potential gold ore deposits in Um Garayat, South Eastern Desert, Egypt. Potential polymetallic exploration in the region is also well-known. It includes Au, Ag, Cu, Zn, Pb, and Mo. Field geology, remote sensing, and geophysical investigations have been conducted in the vicinity of the ancient gold mine to investigate the distribution of the mineralised ore deposits in the Um Garayat region vertically and horizontally. To validate results, field geologic studies were conducted across numerous traverses guided by remote sensing. The results of this investigation demonstrate that low resistivity and high chargeability were indicative of ore deposit regions in the geophysical data. The subsurface magnetic susceptibility distribution validates the area's complexity. According to an integrated interpretation of the collected results, the new possible potential ore deposits are associated with hydrothermally altered zones associated with fracture zones and faults present in the form of zones of varying thicknesses. In Um Garayat, recently discovered mineral occurrences are governed by the major faults and the enrichment of hydrothermal fluids along these fault zones.
