It increased the demands on ground-water supplies that prolonged drought and improper maintenance of water resources. So it is necessary to evaluate ground-water resources in the hard rock terrain. In recent years, Remote-Sensing methods have been increasingly recognized as a means of obtaining crucial geoscientific data for both regional and site-specific investigations. This work aims to develop and apply integrated methods combining the information obtained by geo-hydrological field mapping and those obtained by analyzing multi-source remotely sensed data in a GIS environment for better understanding the Groundwater condition in hard rock terrain. In this study, digitally enhanced Landsat ETM+ data was used to extract information on geology, geomorphology. The Hill-Shading techniques are applied to SRTM DEM data to enhance terrain perspective views, and extract Geomorphological features and morphologically defined structures through the means of lineament analysis. A combination of Spectral information from Landsat ETM+ data plus spatial information from SRTM-DEM data is used to address the groundwater potential of alluvium, colluvium, and fractured crystalline rocks in the study area. The spatial distribution of groundwater potential zones shows regional patterns related to lithologies, lineaments, drainage systems, and landforms. High-yielding wells and springs are often related to large lineaments and corresponding structural features such as dykes. The results show that the combination of remote sensing, GIS, traditional fieldwork, and models provide a powerful tool for water resources assessment and management, and groundwater exploration planning.
This article explored mineral resources and their relation to structural settings in the Central Eastern Desert (CED) of Egypt. Integration of remote sensing (RS) with aeromagnetic (AMG) data was conducted to generate a mineral predictive map. Several image transformation and enhancement techniques were performed to Landsat Operational Land Imager (OLI) and Shuttle Radar Topography Mission (SRTM) data. Using band ratios and oriented principal component analysis (PCA) on OLI data allowed delineating hydrothermal alteration zones (HAZs) and highlighted structural discontinuity. Moreover, processing of the AMG using Standard Euler deconvolution and residual magnetic anomalies successfully revealed the subsurface structural features. Zones of hydrothermal alteration and surface/subsurface geologic structural density maps were combined through GIS technique. The results showed a mineral predictive map that ranked from very low to very high probability. Field validation allowed verifying the prepared map and revealed several mineralized sites including talc, talc-schist, gold mines and quartz veins associated with hematite. Overall, integration of RS and AMG data is a powerful technique in revealing areas of potential mineralization involved with hydrothermal processes.
A geologic and geomorphologic study aimed at solving some geological and geotechnical problems, regarding the massive seepage of meteoric waters in the coastal cliffs of the Island of Procida (Naples Bay, Southern Italy) composed of both tuffs and loose pyroclastic deposits, has been carried out in the geosites of Terra Murata (Middle Ages village and coastal cliff towards the Corricella Bay) and Centane-Panoramica (coastal cliff facing on the Tyrrhenian Sea).
A detailed geologic and geomorphologic survey has allowed to suggest solutions to the applied geological and geotechnical problems related to the occurrence of massive seepages of waters at the physical interface between pyroclastic rocks and loose pyroclastic deposits, characterized by different density, permeability and porosity and also controlled by a dense network of fractures, involving the pyroclastic deposits cropping out in the selected areas.
Field sampling and geotechnical laboratory analyses have been carried out to calculate the values of main geotechnical parameters of the yellow tuffs cropping out at the Terra Murata Promontory. At the same time, a detailed monitoring of the seepages of waters has been carried out through a detailed geological survey of the tuff outcrops of the promontory. The obtained results have suggested a strong control from both the geomorphologic instability of the coastal cliff and tectonic setting. At the Centane-Panoramica geosite, the geological survey, coupled with geotechnical analyses and standard penetrometric tests, has accordingly evidenced that the geomorphologic instability was mainly concentrated in the sectors of the tuff coastal cliffs facing seawards towards the Tyrrhenian Sea.
The sea level rise under global climate change and coastal floods caused by extreme sea levels due to the high tide levels and storm surges have huge impacts on coastal society, economy, and natural environment. It has drawn great attention from global scientific researchers. This study examines the definitions and elements of coastal flooding in the general and narrow senses, and mainly focuses on the components of coastal flooding in the narrow sense. Based on the natural disaster system theory, the review systematically summarizes the progress of coastal flood research in China, and then discusses existing problems in present studies and provide future research directions with regard to this issue. It is proposed that future studies need to strengthen research on adapting to climate change in coastal areas, including studies on the risk of multi- hazards and uncertainties of hazard impacts under climate change, risk assessment of key exposure (critical infrastructure) in coastal hotspots, and cost-benefit analysis of adaptation and mitigation measures in coastal areas. Efforts to improve the resilience of coastal areas under climate change should be given more attention. The research community also should establish the mechanism of data sharing among disciplines to meet the needs of future risk assessments, so that coastal issues can be more comprehensively, systematically, and dynamically studied.
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