Arabian Journal of Geosciences最新文献

Rockfall, a rapid and high-impact landslide phenomenon, poses significant risks to lives, infrastructure, and transportation routes in hilly and mountainous regions. This hazard is characterized by sudden occurrences, widespread impact, fluctuating magnitudes, randomness, and a high fatality rate. The present study aims to provide a knowledge base for stakeholders in infrastructure projects in hilly regions by consolidating findings from reported studies on rockfall. Through a review of reported studies, three key aspects of rockfall are discussed: kinematics, source zone identification, and modelling approaches. Factors influencing rockfall detachment, modes of motion, impact force, and fragmentation are discussed, along with challenges in identifying potential source zones and proposed advanced methodologies for more precise identification and monitoring. Various modelling approaches for assessing rockfall characteristics and trajectories are evaluated, emphasizing the significance of numerical simulations and 3D modelling for accurate evaluation and mitigation strategy assessment. The study also highlights limitations in current modelling approaches and outlines future research directions including the integration of vegetation-related factors, incorporation of fragmentation phenomenon, utilization of advanced technologies for source zone identification, and advancements in rockfall detection and prediction through deep learning techniques. The ultimate goal is to apprise the stakeholders about present tools and techniques for conducting detailed rockfall trajectory simulation and prediction, so that the most suitable rockfall mitigation and/or protection strategy can be selected and implemented based on the specific characteristics of the site.

This paper presents the effects of the hydroelectric reservoir on the water quality in Bajo Anchicaya, a hydropower plant in the southwest of Colombia. The study implicated the comparison of water quality at five sites: before the reservoir, entering the reservoir, at the intake, in the reduced channel, and downstream of the hydropower plant discharge. The data collected were analyzed with the analysis of variance (ANOVA) statistical tool to investigate the significance of the reservoir, season, and the hydropower plant operation on the water quality. The IPOMO (pollution index by organic matter) showed that contamination by organic matter in all cases was none or low, the IPOSUS (pollution index by suspended solids) showed that there was no contamination by suspended solids, and the WQI (water quality index) showed good results. From the ANOVA results, season (flow) and hydropower plant are all significant about the water quality. ANOVA also showed a positive effect of the hydropower plant operation on water quality in terms of the Settleable solids and electrical conductivity in the water. Studies like these can improve the understanding of the influence of reservoirs and hydropower plants on water quality to implement water resource management strategies that maintain good water quality indices and prevent its deterioration.

As the need for food crops and other agricultural goods continues to rise, there is an apparent shift towards intensive agricultural land usage and growth in the Koch Bihar district of West Bengal. However, the quantity of land accessible for agriculture, its location and its suitability for farming have not been adequately investigated. Finding suitable land for agriculture in the Koch Bihar district with the aid of multiple physical, hydrological, climatic and infrastructural variables is the primary objective of this present study. Therefore, eighteen causative factors, including geomorphology, slope, elevation, land use and land cover, soil texture, rainfall, groundwater depth, modified soil adjusted vegetation index, temperature, river density, topographic wetness index, distance from road, organic carbon, soil pH, total nitrogen, cation exchange capacity, bulk density, and silt particles, were considered for land suitability analysis using Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and Vise Kriterijumska Optimizacijaik Ompromisno Resenje (VIKOR) models. Results showed that in the TOPSIS model, most of the region (36.88%) was classified as moderately suitable, followed by 27.60% as marginally suitable, 17.87% as highly suitable, 14.57% as currently not suitable and 3.08% as unsuitable for agriculture. In contrast, 34.26% of the region was categorized as moderately suitable and 20.56% as highly suitable in the VIKOR model. 350 Ground Control Points (GCP) from the study area that represented a variety of topographical and LULC conditions were examined for the model validation. With an appropriate degree of discrimination, shown by the area under the curve value of 0.911, VIKOR has demonstrated a great result between the two models. Identifying and mapping suitable agricultural land is essential for sustainable development because it provides food security, optimizes resource usage, protects the environment, enables land use planning and promotes economic growth.

Geophysical electrical resistivity surveys were carried out in a small lake named as “Nagi lake” located at Namthang, South District, Sikkim, India, for determining the source of in-situ seepage of lake water. Preliminary investigation suggests that the water seepage problem increased after the extension of the lake or after making a check dam surrounding the extended lake. The present study characterizes the origin of water seepage through an unknown fracture in the subsurface of “Nagi Lake.” Seepage path directions were demarcated with the help of an Azimuthal method, whereas sites of fractured areas causing lake water leakages were analyzed via Electrical sounding and profiling techniques. Maps of the fractured zone were developed with the help of a statistical analysis method, also known as the factor method of the traditional vertical electrical sounding (VES) that is ambiguous in method of curve matching. Main emphasis was given to locate subsurface fractures and their orientation. Delineation of location of subsurface fractures and their treatment will aid in minimizing the seepage of water from the lake. Retention of water throughout the year in lake will boost tourism near Nagi Lake area as well as aid in promoting water security in the region.

Unconventional oil and gas resources are characterized by low abundance and strong heterogeneity. Effective sweet spot prediction and mining technology are important for their efficient development. At present, the exploration and development of coalbed methane in the Santanghu Basin is still in the initial stage. Many problems in coalbed methane sweet spot prediction and mining technology seriously restrict the efficient development of coalbed methane resources. In order to study the most suitable evaluation indexes and methods for sweet spot prediction of coalbed methane development in Tiaohu-Malang Depression of Santanghu Basin, various technical means such as high-pressure mercury injection experiment, liquid nitrogen adsorption, and nuclear magnetic resonance are jointly used to analyze the occurrence state and mining technical conditions of coalbed methane in this area, establish a coalbed methane resource evaluation system, and accurately predict the sweet spot area of coalbed methane development. The results show that the main buried depth of the No.9 coal seam of Xishanyao Formation in Tiaohu-Malang Depression is 600–2600 m, and the thickness of coal seam is 5.0–60.9 m. The proportion of pore size volume of No.9 coal seam in the T1 well is mainly large pores and micropores, the proportion of mesopores is slightly smaller, and the specific surface area is opposite. The open pores of coal samples are more developed and the connectivity is better. The smaller pore size section of the coal sample is larger. When the P/P₀ value of the coal sample is about 0.5, there are sudden drop points and more ink bottle-shaped pores are developed. The lithology of the roof and floor is mainly mudstone, and the occurrence condition of coalbed methane is superior. Based on the geological conditions of coalbed methane in this area and the experience of coalbed methane exploration and development at home and abroad, 14 index evaluation indexes such as coal seam thickness, burial depth, lithology of coal seam roof and floor, structure, and so on are optimized and optimized. The sweet spot area of coalbed methane (type I area) is predicted to be mainly distributed in the northeast of Tiaohu Depression and the west of Malang Depression. Taking T1-5 well as an example, the five-stage dual-pressure control method is adopted in the drainage system. The bottom well flow pressure drop is controlled to be ≤ 0.02 MPa/d in the pressure holding and production release stages, and the bottom well flow pressure drop is ≤ 0.01 MPa/d in the stable production stage. The above methods and technologies have achieved initial results in the development of well T1-5, with the highest gas production of 2297 m³/d and the average gas production of 1300 m³/d, showing good gas production effect, which has important guiding significance for the subsequent efficient development of low-rank coalbed methane in Santanghu Basin.

Land use changes from year to year due to natural and human-made factors are a serious cause of the degradation of soil properties. Therefore, this study aimed to investigate the impact of land use land cover changes on selected soil physicochemical properties and soil organic carbon stocks in Kochore district, Southern Ethiopia. Satellite images (2000, 2010, and 2020) were used as sources of information for land use and land cover analysis using ArcGIS 10.3 and ERDAS Imagine 2014 software. Three land use types (cultivated, agroforestry, and grazing land) were identified through field surveys and satellite image analysis. Soil samples were collected at different depths (0–20 cm and 20–40 cm), and selected soil properties were analyzed. The results indicate that geospatial data of the land cover of agroforestry continuously increased and a decrease in grazing and cultivated in the given periods of 2000, 2010, and 2020, and soil properties revealed such as sand, bulk density, organic carbon, total nitrogen, pH, cation exchange capacity, and exchangeable bases were significantly (P < 0.001) affected by land use and soil depth. The highest content of OC (2.37), Av.P. (3.36), and TN (0.13) was observed on agroforestry land, and the lowest 1.43 and 0.08 was OC and TN respectively. The highest value of soil organic carbon stock (60.2 mg ha⁻¹) was observed in AFL. The study suggests the deterioration of soil properties under cultivated and grazing land, emphasizing the importance of sustainable integrated soil fertility management to optimize and maintain favorable soil physicochemical properties.

The granite rocks at the Abu Marwa-Abu Harba area, located at the North Eastern Desert, are classified into trondhjemite, syenogranite, and alkali feldspar granite. They are formed through the Neoproterozoic late to post-orogenic period (~ 600 Ma). The common fault trends in the area based on their number and length proportions are NE-SW, ENE-WSW, WNW-ESE, E-W, N-S, NNE-SSW, NNW-SSE, and NW–SE. The study area is characterized by the abundance of joint systems and was divided into shear and tension joints based on their tectonic origin. Mineralogicaly, the trondjhmite consists of plagioclase, quartz, k-feldspar, biotite, and hornblende. On the other hand, the syenogranite and alkali feldspar granite are mineralogicaly similar and composed of plagioclase, quartz, k-feldspar, biotite, and hornblende but the k-feldspar and quartz in the alkali feldspar granites are more abundant relative to the syenogranite. The Abu Marwa-Abu Harba granite rock types are classified as peraluminous, Fe-rich granites with calc-alkaline and highly fractionated I-type affinity. The trondhjemite has a significantly lower content of TiO₂, CaO, K₂O, Ba, Rb, Sr, Zr, and ƩREE than the syenogranite and the alkali feldspar granite. The trondhjemite displays a gullwing-shaped REE pattern with deeper negative Eu anomaly while the syenogranite and the alkali feldspar granite are rather smooth and subparallel with negative Eu anomaly. The late orogenic trondjhmite was suggested to be generated by partial melting of the mantle source followed by fractional crystallization of k-feldspar, plagioclase, and apatite phases. On the other hand, the post-orogenic syenogranite and alkali feldspar granite were generated by partial melting of the upper crust at different depths followed by fractional crystallization. The fractionated phases were plagioclase, k-feldspar, biotite, hornblende, apatite, and titanite. In addition, the hydrothermal volatile-rich fluids played a role in the formation and generating of the studied post-orogenic syenogranite and alkali feldspar granite.

Overburden dumping is an important issue in consideration of economy and safety for surface mining of coal. The higher slope angle and increased dump height improve the economic benefits, however decrease the stability of the dumps. Dumping methods are classified as (i) end-tipping method and (ii) paddock-dumping method. However, the stability analysis models practised for both the cases are same. The dump slope stability models consider internal friction angle, cohesion and some other properties as the essential parameters affecting the stabilising and destabilising forces. These parameters are significantly changes with the types and sizes of the rock materials. While the dumping methods are different, these properties are changing at different depths of dump. This consideration is missing in the current dump slope stability modelling. This paper focusses on the comparative analysis of stability achieved by forming an overburden dump by an end-dumping approach as well as the paddock approach. From a dump stability analysis, it is found that end dumping exhibits a better factor of safety up to a dump height of 90 m (3 benches of 30 m each) and paddock dumping exhibits better factor of safety than the end-dumping method beyond that and up to a dumb height of 150 m. The paddock-dumping method poses a better factor of safety as compared to the end-dumping method as the number of benches goes up. The reason for higher safety factor in paddock dumping as compared to end dumping may be attribute to the better size distribution and compaction due to machine movements.

Geothermal energy in shallow depth is a locally generated, inexpensive, green renewable energy source. It has proven to be a desirable alternative to fossil fuels for building heating and cooling systems. Horizontal ground heat exchangers (HGHE) coupled to a ground source heat pump are among the shallow geothermal systems. The objective of this study is to investigate the thermal performance of a horizontal U-shaped geothermal heat exchanger for heating and cooling buildings in a region located in northwestern Algeria. Therefore, a three-dimensional transient numerical model based on the finite element method is established using COMSOL multiphysics software. The atmosphere-soil-HGHE interaction and moisture transfer in unsaturated soils are taken into account in this modeling. The effect of pipe length and fluid flow velocity on the performance of horizontal geothermal heat exchangers is also highlighted by this work. The study’s main findings indicate that the heat exchanger’s thermal capacity in summer is approximately 18.11% higher than in winter. This is due to a larger temperature difference between the inlet and outlet water in summer (2.31°C) compared to winter (1.72°C), improving the heat exchanger’s efficiency during summer. The long heat exchange tube is intended to enhance heat transfer. However, the effectiveness of the HGHE is adversely affected by the fact that as fluid velocity rises.

Technological Accidents Triggered by Natural Events (Natech) incidents are occurring more frequently worldwide, driven by rapid industrialization, climate change, and human-induced risks. Understanding all the dynamics of Natech risk is highly complex. Frequently, interactions between multiple hazards are disregarded. Studies have primarily focused on individual natural hazards, examining the most common damage scenarios, resulting in a recurring research cycle in Natech studies and potential oversight of other natural hazards (risk myopia). Sinkholes are becoming an increasing threat to industries every year, with the potential to escalate. Moreover, this hazard can also be triggered by anthropogenic stressors. The sinkhole threat needs to receive adequate attention in Natech research. Another threat, induced seismicity caused by anthropogenic activities, needs to be sufficiently addressed in the risk assessment of Natech accidents. The focal industries of Natech research include the storage, chemistry, and petrochemical sectors. The need for studies in the manufacturing industry (glass, metal, casting, textiles, furniture, automotive) underscores a gap in the literature. This study aims to present an argument that is both different and supportive of prevailing approaches in the literature by drawing attention to anthropogenic activities, often overlooked in the analysis of technological accidents triggered by natural hazards, the presence of potentially dangerous natural events, and industrial sectors that have been either wholly overlooked or the subject of limited research.