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Unraveling groundwater potential zones from alluvial plains using decision making method: A river scale analysis 利用决策方法揭示冲积平原地下水潜力带:河流尺度分析
Pub Date : 2025-09-23 DOI: 10.1016/j.geogeo.2025.100461
Adesh Patel , M.M. Singh , S.C. Bhatt , Narendra Kumar Rana , Sudhir Kumar Singh , Nirmal Kumar , Hrithik Sachan
Due to climate change many basins are under water stress condition due to erratic rainfall. Hence, we aimed to study rainfall pattern over the last thirty-two years and to identify the new groundwater potential zones (GWPZs) using the remote sensing-based products, meteorological, hydrogeological, and groundwater level data in the lower Rapti River Basin (LRRB). The monthly data of thirty-two years (1990–2022) of eight stations viz. Balrampur, Shravasti, Siddharth Nagar, Maharajganj, Sant Kabir Nagar, Gorakhpur, Deoria, and Kushinagar were tested for standardized precipitation index (SPI) at multi-time scale (SPI-1, SPI-3, SPI-6, SPI-9, SPI-12, and SPI-24) to decipher wetness and dryness condition in the area. Afterwards, impact of rainfall was correlated with surface drainage characteristic and sub-surface recharge zone. Henceforth, different data sets pertaining to lithology, rainfall, geology, drainage density, geomorphology, land use/land cover, soil, slope and elevation were used to delineate GWPZ. Relative importance of thematic layers and weights on Saaty’s scale was determined by analytical hierarchy process (AHP) in order to normalize and standardize the weights. Eventually, in the GIS environment all thematic layers were combined using the weighted overlay method (WOM) for delineation of GWPZ. Result of GWPZ was validated with groundwater level and soil moisture data and categorized as excellent, good, fair and poor. The majority of area is under the category of good and fair GWPZs.
由于气候变化,许多流域由于降水不稳定而处于水胁迫状态。因此,本研究旨在利用遥感产品、气象、水文地质和地下水位数据,研究拉普提河下游近32年的降雨模式,并确定新的地下水潜势区。利用Balrampur、Shravasti、Siddharth Nagar、Maharajganj、Sant Kabir Nagar、Gorakhpur、Deoria和Kushinagar等8个站点1990-2022年32年的月数据进行了多时间尺度(SPI-1、SPI-3、SPI-6、SPI-9、SPI-12和SPI-24)的标准化降水指数(SPI)测试,以解释该地区的干湿状况。降雨的影响与地表排水特征和次地表补给带相关。此后,使用不同的数据集,包括岩性、降雨、地质、排水密度、地貌、土地利用/土地覆盖、土壤、坡度和高程,来划定GWPZ。采用层次分析法(AHP)确定主题层与权重在Saaty量表上的相对重要性,以实现权重的规范化和标准化。最后,在GIS环境下,使用加权叠加法(WOM)将所有主题层组合在一起进行GWPZ圈定。利用地下水位和土壤湿度数据对GWPZ结果进行验证,并将其分为优、良、一般和差。大部分地区属于良好和公平的gwpz类别。
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引用次数: 0
GIS-driven hybrid multicriteria model for flood susceptibility assessment in a coastal metropolis of Ghana 加纳沿海大都市洪水易感性评价的gis驱动混合多准则模型
Pub Date : 2025-09-22 DOI: 10.1016/j.geogeo.2025.100462
Samuel Yaw Danso
Mapping regions prone to flooding constitutes a crucial step toward developing localized solutions for flood preparedness and mitigation. This study presents a geographic information system (GIS)-driven approach that combines the decision-making trial and evaluation laboratory (DEMATEL), criteria importance through intercriteria correlation (CRITIC), and simple additive weighting (SAW) methodologies to identify flood-prone areas in the Sekondi-Takoradi Metropolis (STM), Ghana. The study's originality lies in using the hybrid DEMATEL-CRITIC-SAW model for flood susceptibility assessment, a novel integration of decision-making methods and analytical techniques not previously applied together for this purpose. This novel framework provides a comprehensive approach to analyze relationships among 11 flood-inducing variables, determine variable importance, and integrate these findings to produce a more accurate and robust flood susceptibility map. The results reveal a constructed network structure that highlights the complex relationships and dependencies among the variables. Among the assessed criteria, stream power index was identified as the most significant factor due to its high total interaction with other criteria. The flood susceptibility zones within STM are classified into five levels: very low (15%), low (27%), moderate (21%), high (22%), and very high (14%). Notably, the coastal and central sections of STM were marked as areas with moderate to very high flood susceptibility. The results, measured using the area under the curve, indicate that the proposed approach achieved a score of 0.947, demonstrating its superior performance over other existing hybrid models in the literature. The method provides actionable recommendations to authorities in STM for developing flood prevention/mitigation measures.
绘制易受洪水影响地区的地图,是朝着制定地方防洪和减灾解决方案迈出的关键一步。本研究提出了一种地理信息系统(GIS)驱动的方法,该方法结合了决策试验和评估实验室(DEMATEL)、通过标准间相关性(CRITIC)确定标准重要性(critical)和简单相加加权(SAW)方法,以确定加纳Sekondi-Takoradi大都市(STM)的洪水易发地区。该研究的独创性在于使用混合的dematel - critical - saw模型进行洪水易感性评估,这是一种新的决策方法和分析技术的整合,以前从未用于此目的。该框架提供了一种全面的方法来分析11个洪水诱发变量之间的关系,确定变量的重要性,并将这些发现整合起来,以产生更准确、更可靠的洪水易感性图。结果揭示了一个构建的网络结构,突出了变量之间的复杂关系和依赖关系。在评价标准中,水流功率指数因其与其他标准的高度相互作用而被确定为最重要的因素。将STM内的洪水易感性区划分为5个级别:极低(15%)、低(27%)、中(21%)、高(22%)和极高(14%)。值得注意的是,STM的沿海和中部地区被标记为中等至非常高的洪水易感性地区。使用曲线下面积测量的结果表明,该方法的得分为0.947,表明其优于文献中其他混合模型的性能。该方法为STM当局制定防洪/减灾措施提供了可行的建议。
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引用次数: 0
Modelling environmental fragility in an industrial landscape: An integrated remote sensing-GIS framework for sustainable planning in Brahmani-Dwarka Interfluve 工业景观中的环境脆弱性建模:Brahmani-Dwarka Interfluve可持续规划的综合遥感- gis框架
Pub Date : 2025-09-18 DOI: 10.1016/j.geogeo.2025.100460
Bhaskar Mandal, Kaushalendra Prakash Goswami, Sharmistha Mondal
Evaluating environmental vulnerability is crucial for efficient and sustainable management, particularly in regions that are ecologically sensitive and experiencing rapid transformations. Thus, the main goal of this study is to evaluate the environmental fragility of the Brahmani-Dwarka Interfluve by integrating key natural and human-induced factors through the analytical hierarchy process (AHP) and fuzzy analytical hierarchy process (FAHP) within a remote sensing and geographic information systems (RS-GIS) framework. To achieve this, ten unique factors influencing potential environmental fragility (PEF) were analyzed, along with four new factors to tackle emerging fragility (EEF). This study holds significant value as it focuses on a region profoundly affected by stone crushing industries, which encounter considerable threats of environmental harm. The results of the PEF model showed that high and very high fragility zones accounted for 23.96% and 22.38% of the area, according to the AHP and FAHP models. Similarly, EEF models highlighted a growing fragility, with FAHP and AHP indicating that 27.85% and 16.80% of the region were categorized as having high and very high fragility. Hotspot analysis indicated that environmentally fragile hotspots constituted 21.07% and 31.46% of the area in the AHP and FAHP-based models, respectively. ROC validation indicated that FAHP demonstrated superior performance compared to AHP in both PEF and EEF models, highlighting its exceptional predictive accuracy and reliability. The observed negligible difference between high and low sensitive parameters was 0.866% in FAHP-based PEF and 0.532% in FAHP-based EEF, indicating the models’ reliability. The findings of the study will help policymakers, planners, and stakeholders to develop environmentally resilient strategies and policies as well as achieve sustainability in the study region.
评价环境脆弱性对于有效和可持续的管理至关重要,特别是在生态敏感和经历迅速变化的区域。因此,本研究的主要目标是在遥感和地理信息系统(RS-GIS)框架下,通过层次分析法(AHP)和模糊层次分析法(FAHP),综合自然因素和人为因素,评价婆罗门-德瓦卡断裂带的环境脆弱性。为实现这一目标,分析了影响潜在环境脆弱性(PEF)的10个独特因素,以及应对新兴脆弱性(EEF)的4个新因素。这项研究具有重要的价值,因为它关注的是一个深受石料破碎行业影响的地区,这些行业面临着相当大的环境危害威胁。PEF模型的结果显示,AHP和FAHP模型显示,高脆弱区和极高脆弱区分别占总面积的23.96%和22.38%。同样,EEF模型强调了日益增长的脆弱性,FAHP和AHP表明该地区27.85%和16.80%的地区被归类为高脆弱性和非常高脆弱性。热点分析表明,基于AHP和fahp模型的环境脆弱热点区面积分别占21.07%和31.46%。ROC验证表明,与AHP相比,FAHP在PEF和EEF模型中都表现出更好的性能,突出了其卓越的预测准确性和可靠性。基于fahp的PEF和基于fahp的EEF的高低敏感参数差异可忽略不计,分别为0.86%和0.532%,表明模型具有较高的可靠性。研究结果将有助于决策者、规划者和利益相关者制定环境弹性战略和政策,并在研究区域实现可持续性。
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引用次数: 0
Developing a riverbank erosion susceptibility index: A pragmatic approach to reveal the level of vulnerability in coastal Bangladesh 开发河岸侵蚀敏感性指数:揭示孟加拉国沿海地区脆弱性水平的实用方法
Pub Date : 2025-09-16 DOI: 10.1016/j.geogeo.2025.100459
Arabe Khan , Md Mahmudul Hasan Rakib , Irteja Hasan , Apurba Roy , Mehedi Hasan Ovi , Md Mostafa Jaman Rabby , Raian Islam Evan , Nusrat Jahan Suborna , Maksudur Rahman , Rahat Khan , Dhiman Kumer Roy
Riverbank erosion is one of the significant natural hazards affecting the livelihoods of communities living along riverbanks in Bangladesh. This study develops a novel riverbank erosion susceptibility index (RESI) to quantitatively assess community susceptibility to this hazard. The RESI framework integrates five core dimensions: exposure, susceptibility, sensitivity, adaptability, and resilience, encompassing 34 context-specific indicators derived from household surveys, interviews, and field observations. The RESI scoring scale ranges from -1 (most resilient) to +1 (most susceptible), where higher positive scores indicate greater susceptibility to riverbank erosion. The findings in this study conclude that Chadpur Union is the most susceptible (RESI score: 0.47), followed by Shambupur (0.36) and Chanchra (0.29) union. These scores are further validated with historical remote-sensing analysis, and sensitivity tests show that varying indicator weights (equal, expert, or PCA) do not change the relative union ranking, underscoring the model’s robustness. The analysis highlights key drivers of vulnerability: frequent erosion occurrences, high population density along riverbanks, considerable losses in land and assets, and recurrent displacement due to erosion. All three unions are facing significant challenges in building adaptability and resilience, as indicated by low scores in infrastructure, financial resources, and social support systems. The study emphasizes the need for targeted interventions to reduce susceptibility, which include reinforcing protective structures, improving access to financial and technical resources, and promoting livelihood diversification strategies. Integrating the RESI into planning enables decision-makers to prioritize high-risk areas and allocate resources more effectively.
河岸侵蚀是影响孟加拉国沿河社区生计的重大自然灾害之一。本文提出了一种新的河岸侵蚀敏感性指数(RESI)来定量评价群落对河岸侵蚀的易感性。RESI框架整合了五个核心维度:暴露、易感性、敏感性、适应性和复原力,包括34个根据家庭调查、访谈和实地观察得出的具体情况指标。RESI评分范围从-1(最具弹性)到+1(最易受影响),越高的正分数表明越容易受到河岸侵蚀。本研究结果表明,Chadpur工会最易受感染(RESI得分:0.47),其次是Shambupur工会(0.36)和Chanchra工会(0.29)。这些分数通过历史遥感分析进一步验证,敏感性测试表明,不同的指标权重(平等,专家,或PCA)不会改变相对联合排名,强调模型的鲁棒性。该分析强调了脆弱性的主要驱动因素:频繁发生侵蚀、河岸人口密度高、土地和资产的大量损失以及侵蚀导致的经常性流离失所。从基础设施、财政资源和社会支持系统的低得分可以看出,这三个工会在建立适应性和弹性方面都面临着重大挑战。该研究强调需要有针对性的干预措施来降低易感性,其中包括加强保护结构,改善获得财政和技术资源的机会,以及促进生计多样化战略。将RESI纳入规划,使决策者能够优先考虑高风险领域,并更有效地分配资源。
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引用次数: 0
Geospatial flood susceptibility modelling using analytical hierarchy process: A case study in the south-central coastal region of Bangladesh 基于层次分析法的地理空间洪水易感性模型:以孟加拉国中南部沿海地区为例
Pub Date : 2025-09-09 DOI: 10.1016/j.geogeo.2025.100457
Irteja Hasan , Md Mahmudul Hasan Rakib , Dhiman Kumer Roy , Mehedi Hasan Ovi , Md. Fuad Hasan , Md. Sagirul Islam Majumder
The Patuakhali region is situated in the coastal area of Bangladesh and is bordered by major rivers, which are extremely vulnerable to foreseeable flooding disasters due to the detrimental effects of climate change. The primary objective of this study is to create a flood susceptibility map using AHP, GIS, and Remote Sensing techniques. The flood hazard map was constructed using seven important causative factors, where elevation (32 %) is the most influential in creating flood hazards, followed by slope (22 %) and drainage density (14 %). The flood hazard map shows that 10.30 % area is very highly hazardous, 22.20 % is in high, 30.45 % is moderate, 26.06 % is low, and 10.99 % area is in very low hazard zone in the study area. The flood vulnerability map was developed using four key factors: population density, distance from roads, land use/land cover (LULC), and NDVI, with population density emerging as the most influential factor, contributing 45 % to the overall vulnerability assessment. The map indicates that 30 % of the area is classified as very high, 23 % as high, 22 % as moderate, 17 % as low, and 9 % as very low vulnerability. Likewise, the flood hazard and vulnerability maps were overlaid to construct a flood risk map. In the final AHP-GIS flood risk map, 10 % of regions were classified as very high risk, 22 % as high risk, 28 % as moderate risk, 24 % as low risk, and 16 % as very low risk. The information contained in these maps will be beneficial to decision-makers in implementing flood-mitigation policies in priority areas of sustainable development, as well as in preventing and managing floods in the coastal belt of Bangladesh. Further analysis, which includes data on population and building density, proximity to nature, and economic and social activities, will enable the enhancement of sustainability in addition to this study.
Patuakhali地区位于孟加拉国沿海地区,与主要河流接壤,由于气候变化的不利影响,这些河流极易受到可预见的洪水灾害的影响。本研究的主要目的是利用层次分析法、地理信息系统和遥感技术创建洪水易感性图。洪水灾害图是由七个重要的因素构成的,其中海拔(32%)对洪水灾害的影响最大,其次是坡度(22%)和排水密度(14%)。洪涝灾害分布图显示,研究区有10.30%的区域为极高危险区,22.20%为高危险区,30.45%为中度危险区,26.06%为低危险区,10.99%的区域为极低危险区。利用人口密度、与道路的距离、土地利用/土地覆盖(LULC)和NDVI四个关键因素绘制洪水脆弱性图,其中人口密度是影响最大的因素,对总体脆弱性评价的贡献率为45%。地图显示,30%的地区被划分为非常高,23%为高,22%为中等,17%为低,9%为非常低。同样,将洪水危害和脆弱性图叠加,构建洪水风险图。在最终的AHP-GIS洪水风险图中,10%的地区被分类为非常高风险,22%为高风险,28%为中等风险,24%为低风险,16%为极低风险。这些地图所载的信息将有助于决策者在可持续发展的优先领域执行减轻洪水的政策,以及在孟加拉国沿海地带预防和管理洪水。进一步的分析,包括人口和建筑密度、与自然的接近程度以及经济和社会活动的数据,将有助于在本研究的基础上提高可持续性。
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引用次数: 0
The supergiant Witwatersrand Goldfield: A result of anhydrous mantle degassing on Earth’s earliest supercontinent 威特沃特斯兰德金矿:地球上最早的超大陆上无水地幔脱气的结果
Pub Date : 2025-09-09 DOI: 10.1016/j.geogeo.2025.100456
Liang Zhang , David I. Groves , John L. Walshe
The origin of the supergiant high grade Witwatersrand gold deposits has attracted debate for several decades with modified gold placer models contrasting with orogenic gold crustal metamorphic models. Neither explains the anomalous quantities of gold, pyrobitumen, and ‘carbon leaders’ in the Basin during the otherwise gold- and carbon-poor Mesoarchean. The Witwatersrand, part of a trilogy with the Bushveld Complex PGE-Cr-Fe-Ti-V and Kaapvaal diamond fields as the largest deposits globally, is unique, requiring consideration of a tectonic-scale non-conventional model to explain it.
Host to the Witwatersrand Basin, the Kaapvaal Craton represents a continental block within the first supercontinent Ur. Iron-Ni alloy inclusions and terrestrial-like C isotopes in CLIPPIR diamonds within the Craton provide evidence for the addition of metals, including those that later resided in cumulate slurries in the giant Bushveld Complex, to the mantle during Archean core-mantle-crust overturns. Mesoarchean mantle degassing is considered the most likely key process for transport of gold by anhydrous fluids as indicated by CH₄ and H₂ inclusions in CLIPPIR diamonds. The lithosphere-scale Colesberg suture on the western margin of the Witwatersrand Basin, the entry for sedimentary fans during deposition of the Central Rand gold reefs and carbon leaders, represents reactivation of a subduction zone during breakup of Ur at ca. 3.0–2.9 Ga. It is proposed that this suture, recognized as a break in lithosphere profiles, acted as the conduit for CH₄ and H₂ fluids carrying Au in metal hydrides to the mid-upper mantle where CH₄ and H₂ dissociated to form hydrocarbons which extracted additional Au from mantle sulfides. The gold and hydrocarbons were then exhaled on to the western hinterland of the Witwatersrand Basin to provide the anomalous quantity of Au and C required to explain both the Witwatersrand endowment and why such a unique conjunction of factors has never occurred again in Earth history, although most subsequent primary gold-rich deposits are also now considered to have had a mantle connection.
摘要威特沃特斯兰德超巨型高品位金矿床的成因争论了几十年,修正的金砂矿模型与造山带金地壳变质模型进行了对比。两者都不能解释中太古宙盆地中金、焦沥青和“碳先导物”的异常数量。威特沃特斯兰德(Witwatersrand)与布什维尔德(Bushveld)复杂的PGE-Cr-Fe-Ti-V和Kaapvaal钻石矿是全球最大的矿床,是三部曲的一部分,它是独一无二的,需要考虑构造尺度的非常规模型来解释它。Kaapvaal克拉通是威特沃特斯兰德盆地的所在地,代表了乌尔第一超大陆内的一个大陆块。克拉通内CLIPPIR钻石中的铁镍合金包裹体和类陆相C同位素为太古宙核-幔-壳翻覆期间地幔中添加金属提供了证据,包括后来在巨大的布什维尔德杂岩中沉积的金属。中太古代地幔脱气被认为是无水流体输运金最可能的关键过程,CLIPPIR钻石中的CH₄和H₂包裹体表明了这一点。Witwatersrand盆地西缘岩石圈尺度的Colesberg缝合线是中央兰德金礁和碳先导沉积时期沉积扇的入口,代表了约3.0 ~ 2.9 Ga乌尔断裂期间俯冲带的重新激活。这条断裂带是岩石圈剖面上的断裂,是携带金属氢化物中的金的CH₄和H₂流体进入中上地幔的通道,在那里CH₄和H₂解离形成碳氢化合物,从地幔硫化物中提取额外的金。然后,金和碳氢化合物被呼到威特沃特斯兰德盆地的西部腹地,提供了异常数量的金和碳,这就解释了威特沃特斯兰德的禀性,以及为什么这种独特的因素结合在地球历史上再也没有发生过,尽管大多数后来的原生富金矿现在也被认为与地幔有联系。
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引用次数: 0
Paleoproterozoic rift-related volcanism and associated ore mineralization in the Alwar Basin, India 印度阿尔瓦尔盆地古元古代裂谷相关火山作用及成矿作用
Pub Date : 2025-09-06 DOI: 10.1016/j.geogeo.2025.100455
R. Sajeev , Dinesh Pandit , M. Santosh , Cheng-Xue Yang
Alwar Basin, located within the North Delhi Fold Belt (NDFB) of India, is a key area to study the processes of Precambrian geological history and related mineralization. In this study, we document two discrete pulses of volcanic activity in the Alwar Basin, dated at 1.865 ± 0.021 Ga and 1.635 ± 0.017 Ga, recorded by weighted‐mean zircon U–Pb ages. These episodic eruptions generated a compositional spectrum from basalt through rhyolite, emplacing volcanic sequences in a shallow‐marine, within‐plate rift environment. Subsequent percolation of metal‐rich hydrothermal fluids – driven by sustained heat flux and extensional fracturing – focused along stratigraphic contacts and pre‐existing weak planes, precipitating Cu–Pb–Zn sulfide mineralization within quartz–carbonate veins. Geochemical signatures, including peraluminous major‐ and trace‐element patterns and characteristic REE anomalies, further attest to syn-rift magma evolution and crustal assimilation. This pulsatory volcanism and linked hydrothermal activity were pivotal in concentrating base metals, revealing the interplay between Precambrian rifting and ore genesis in the North Delhi Fold Belt.
Alwar盆地位于印度北德里褶皱带(NDFB)内,是研究前寒武纪地质历史和成矿作用过程的重点地区。本文通过加权平均锆石U-Pb年龄记录了阿尔瓦尔盆地火山活动的两个离散脉冲,分别为1.865±0.021 Ga和1.635±0.017 Ga。这些间歇喷发产生了从玄武岩到流纹岩的成分谱,将火山序列置于浅海相板块裂谷环境中。随后,在持续的热通量和伸展性压裂的驱动下,富金属热液沿着地层接触面和预先存在的薄弱面渗透,在石英-碳酸盐脉中沉淀出铜-铅-锌硫化物矿化。地球化学特征,包括过铝主要元素和微量元素模式以及特征REE异常,进一步证明了同裂谷岩浆演化和地壳同化。这种脉动性火山活动和相关的热液活动是贱金属富集的关键,揭示了北德里褶皱带前寒武纪裂陷作用与成矿的相互作用。
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引用次数: 0
Combining MCDM and geospatial techniques to identify groundwater potential zones and trend analysis of rainfall and well water level data: An investigation in the Prayagraj and Kaushambi districts 结合MCDM和地理空间技术确定地下水潜在带和趋势分析降雨和井水水位数据:在Prayagraj和Kaushambi地区的调查
Pub Date : 2025-09-02 DOI: 10.1016/j.geogeo.2025.100454
Swarnim, Jayant Nath Tripathi, Irjesh Sonker, Ritesh Singh
This research employed remote sensing and geographic information system (GIS) to figure out the groundwater potential zones (GWPZ) in the Prayagraj and Kaushambi districts of Uttar Pradesh, India, where groundwater is heavily exploited for agriculture and urbanisation and government policies being implemented for enhancing the groundwater level. The study region contains both (confined and unconfined) type of groundwater. The following variables were utilised to produce groundwater potential zone (GWPZ) maps: geology, precipitation, geomorphology, soil texture, lineament frequency, slope, drainage density, topographic wetness index (TWI), land use and land cover and normalised difference vegetation index (NDVI).
Prior to the fusion of the layers, multicollinearity assessments were performed to ascertain the accuracy of the predictive outcome. The chosen themes were included into a GIS platform with a weighted linear combination, with distinct weights allocated to different themes through the multi-influencing factor (MIF) and analytical hierarchy process (AHP) methodologies. Based on the groundwater prospective zones, the research area was divided into three groups: high potential, moderate potential, and low potential zones. Groundwater potential zones are sequentially identified by the MIF method as follows: High (16.35%; 1173.79 km2), Moderate (76.28%; 5477.24 km2), and Low (7.38%; 529.64 km2), while the AHP method identifies the same zones as follows: High (10.01%; 717.87 km2), Moderate (80.92%; 5810.41 km2), and Low (9.09%; 652.40 km2) in a consecutive manner. The accuracy of the maps was determined by comparing them to well water level data using the receivers operating characteristic curve (ROC). The AHP and MIF approaches yielded accuracy rates of 79.9% and 77% respectively. According to the trend analysis of rainfall for 34 years and water level of wells of 26 years for post-monsoon and pre-monsoon season the rainfall is increasing and groundwater level is decreasing. The GWPZ assessment and monitoring techniques are accurate and fair. Thus, this research is essential for creating a more efficient framework that can speed up groundwater recharge analysis and guide the installation of artificial recharge structures.
本研究利用遥感和地理信息系统(GIS)计算出印度北方邦Prayagraj和Kaushambi地区的地下水潜力区(GWPZ),这些地区的地下水被农业和城市化严重开采,政府正在实施提高地下水位的政策。研究区既有承压和无承压两种类型的地下水。利用以下变量生成地下水潜势带(GWPZ)图:地质、降水、地貌、土壤质地、线条频率、坡度、排水密度、地形湿度指数(TWI)、土地利用和土地覆盖以及归一化植被指数(NDVI)。在层融合之前,进行多重共线性评估以确定预测结果的准确性。将选择的主题纳入加权线性组合的GIS平台,并通过多影响因素(MIF)和层次分析法(AHP)方法为不同主题分配不同的权重。根据地下水远景区划分,将研究区划分为高远景区、中远景区和低远景区。MIF法依次识别出高(16.35%,1173.79 km2)、中(76.28%,5477.24 km2)、低(7.38%,529.64 km2)、AHP法依次识别出高(10.01%,717.87 km2)、中(80.92%,5810.41 km2)、低(9.09%,652.40 km2)。通过使用接收机的工作特征曲线(ROC)将其与井水水位数据进行比较,确定了地图的准确性。AHP和MIF方法的准确率分别为79.9%和77%。根据34年降水和26年井水位的趋势分析,季风后和季风前的降水呈增加趋势,地下水位呈下降趋势。GWPZ评估和监测技术准确、公正。因此,这项研究对于建立一个更有效的框架至关重要,该框架可以加快地下水补给分析并指导人工补给结构的安装。
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引用次数: 0
Uncovering the Late Cretaceous paleoenvironment and paleoclimate of the Agbaja Plateau, Bida Basin, Nigeria: An inorganic geochemical analysis of shales and implications for organic matter enrichment 揭示尼日利亚比达盆地Agbaja高原晚白垩世古环境和古气候:页岩无机地球化学分析及其有机质富集意义
Pub Date : 2025-09-02 DOI: 10.1016/j.geogeo.2025.100452
Olusola J. Ojo , Suraju A. Adepoju , Ayodeji Awe , Moses O. Adeoye , Emmanuel G. Olumayede , Otobong S. Ndukwe , Sikiru O. Abdulraman , Abdulrazaq K. Haruna , Yusuf A. Jimoh
The bulk geochemical composition of the shale samples of the Maastrichtian Patti Formation exposed at the Agbaja Plateau, southern Bida Basin, Nigeria was studied using X-ray fluorescence (XRF) and inductive coupled plasma mass spectrophotometry (ICPMS) techniques. The objectives of this study are to decipher their paleoenvironment, palaeoclimate and examine the influence of the paleogeographic conditions on the hydrocarbon source rock potential. The geochemical proxies indicate that the shales were deposited under oxic and warm and humid conditions. The plots of V/(V + Ni) vs. U/Th and Ni/Co vs. U/Th support the oxic setting for the shales. The slight Ce anomalies (0.93–1.26), ΣREE (39.40–1607.37 ppm) and (La/Yb)N ratio (4.11–10.78 ppm) are in support of the sub-oxic to oxic condition. The studied shales show Th/U values from 1.98 to 4.38 which indicates prevalence of high primary paleoproductivity. The clustering of the analyzed samples near the A-K line in the A-CN-K (Al2O3-CaO + Na2O-K2O) ternary diagram depicts an intense chemical weathering in the source region. In conclusion, the obtained paleogeographic scenario in the study area (warm temperature, high precipitation, oxic to dysoxic condition, and moderate to high primary paleoproductivity) typical of the west Africa upper Cretaceous and freshwater to brackish water environment would have supported the development of moderate organic matter rich source beds with potential for gas and oil in the Bida Basin. This study has underscored the significance of understanding the interplay between sedimentary environment, organic productivity and organic matter enrichment in predicting and exploring hydrocarbon source rocks.
利用x射线荧光(XRF)和电感耦合等离子体质分光光度(ICPMS)技术研究了尼日利亚Bida盆地南部Agbaja高原Maastrichtian Patti组页岩样品的整体地球化学组成。本研究的目的是破译其古环境、古气候,探讨古地理条件对烃源岩潜力的影响。地球化学指标表明,页岩沉积在缺氧和温暖潮湿的条件下。V/(V + Ni) vs. U/Th和Ni/Co vs. U/Th图支持页岩的氧化环境。微量Ce异常(0.93 ~ 1.26)、ΣREE异常(39.40 ~ 1607.37 ppm)和La/Yb N异常(4.11 ~ 10.78 ppm)支持亚氧—氧条件。研究页岩Th/U值为1.98 ~ 4.38,具有较高的原生古生产力。在A-CN-K (Al2O3-CaO + Na2O-K2O)三元图中,分析样品在A-K线附近聚集,说明源区化学风化作用强烈。综上所述,研究区典型的西非上白垩统、淡水-微咸水环境(温、高降水、缺氧-缺氧、初级古生产力中-高)古地理情景支持了比达盆地中富有机质、具油气潜力的烃源层发育。该研究强调了认识沉积环境、有机质生产力和有机质富集之间的相互作用对烃源岩预测和勘探的重要意义。
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引用次数: 0
A review on the application of geophysical methods in civil engineering studies 地球物理方法在土木工程研究中的应用综述
Pub Date : 2025-08-30 DOI: 10.1016/j.geogeo.2025.100453
A.A. Akinlalu , M.M. Futai , D.O. Afolabi , R.M. Abraham-A
This paper reviewed the application of geophysical methods in civil engineering projects by way of subsurface characterization by examining more than 75 publications in peer–reviewed journals. The paper highlighted various geological conditions considered in engineering site characterization and the appropriate geophysical methods such as electrical resistivity tomography, seismic refraction tomography, self-potential, induced polarization, electromagnetic, multichannel analysis of surface waves and magnetic methods used in subsurface characterization. Case studies drawn from 26 publications were presented to show the successful application of geophysical methods in subsurface characterization in relation to civil engineering projects. The paper also highlighted the challenges of geophysical data in civil engineering projects involving ambiguities in data interpretation, complexity in data processing and high noise to signal ratio in culturally noisy environments. Resolutions in the limitations and challenges of geophysical methods in civil engineering characterization were also offered in the paper, chief among them is integrated use of geophysical methods which has gained traction in recent years. Further solutions are incorporating appropriate band pass filters in the design of geophysical equipment’s to enhance signal to noise ratio in culturally noisy environments. Future researches in the use of geophysical methods in subsurface characterization in relation to civil engineering projects should involve joint inversion and modelling of integrated geophysical methods to achieve optimum results for subsurface imaging. Future researches should also incorporate the integration of machine learning and deep learning techniques, which enhance automated interpretation, facilitate anomaly detection, and enable real-time geophysical monitoring in civil infrastructure applications.
本文通过查阅同行评议期刊上发表的75多篇论文,综述了地球物理方法在土木工程项目中地下表征的应用。本文重点介绍了工程场地表征中考虑的各种地质条件,以及相应的地球物理方法,如电阻率层析成像、地震折射层析成像、自电位、感应极化、电磁、多通道表面波分析和地下表征中使用的磁性方法。从26份出版物中提取的案例研究展示了地球物理方法在土木工程项目地下表征中的成功应用。本文还强调了地球物理数据在土木工程项目中的挑战,包括数据解释的模糊性、数据处理的复杂性以及在文化嘈杂环境中的高噪声与信号比。本文还提出了地球物理方法在土木工程表征中的局限性和挑战,其中最主要的是近年来受到关注的地球物理方法的综合应用。进一步的解决方案是在地球物理设备的设计中加入适当的带通滤波器,以提高文化噪声环境中的信噪比。未来在土木工程项目中使用地球物理方法进行地下表征的研究应涉及综合地球物理方法的联合反演和建模,以获得最佳的地下成像结果。未来的研究还应结合机器学习和深度学习技术,以增强自动化解释,促进异常检测,并在民用基础设施应用中实现实时地球物理监测。
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引用次数: 0
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Geosystems and Geoenvironment
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