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排序方式: 共有1005条查询结果,搜索用时 46 毫秒
811.
812.
Kikon  Noyingbeni  Kumar  Deepak  Ahmed  Syed Ashfaq 《GeoJournal》2022,87(4):821-846

Human activities have affected the urban environment resulting in a drastic change in the surface temperature. The impact of urban heat islands is noticeable in urban areas than in rural areas. The thermal band of Landsat 8 data is used to retrieve the spatial distribution of land surface temperature (LST) over Kohima Sadar for the years 2009, 2015 and 2020 with the Mono-window algorithm. Urban Thermal Field Variance Index (UTFVI) is used to assess the ecological condition in the area impacted by LST. Cartosat-1 Digital Elevation Model (Carto DEM) is used to understand the variations of LST and indices values with reference to the elevation profile located at different random points. The variations in the land cover are categorized as per the values of normalized difference vegetation index (NDVI) and built-up density index (BUI). This work estimates the influence of elevation over LST, vegetation, and the built-up area. Results implies a negative correlation between LST and NDVI whereas a positive correlation between LST and BUI. Likewise, NDVI and BUI show a strong negative correlation. It is observed that LST is independent of elevation profile but the variation of LST depends on the impact of change in topography urbanization, deforestation, and afforestation. There is no significant relationship of elevation with the variations in NDVI and BUI values. It is observed that the impact of emissivity influences the estimation of LST values. For the locations having the highest and lowest LST, NDVI, and BUI values, 50 random points are generated for the entire region, and validation is executed with the google earth historical image.

  相似文献   
813.
Natural Hazards - Floods are the most frequent type of natural disaster. It destroys wildlife habitat, damages bridges, railways, roads, properties, and puts millions of people at risk. As such,...  相似文献   
814.
Acta Geochimica - This study focused on water quality and hydro-geochemical processes (evolution, origin) in the Maadher region, central Hodna in Algeria. In recent decades, the excessive...  相似文献   
815.
Surveys in Geophysics - This paper deals with the application of the Ground Penetrating Radar (GPR) method in the assessment of stone monuments. Compilation of published works and a discussion of...  相似文献   
816.
Memon  Manzoor Hussain  Ahmed  Rafiq 《Natural Hazards》2022,111(2):1575-1602

Pakistan, being an agro-based economy, is considered most vulnerable to the impacts of climate change. The country is susceptible to many natural catastrophes and climate-induced events due to intra-geographical and intra-topographical disparities. This paper is an attempt to measure the relative vulnerability of diverse topographies in rural areas of Pakistan using vulnerability and capacity index tool. The results are based on the findings of primary survey data (350 households from 17 rural communities). Accordingly, and as expected, the key relative differences are attributed to topographical conditions besides the basic quandary of rural areas of Pakistan. The topographical attributes are largely linked to the nature of hazards and relative impacts. While the other aspects of vulnerability in all topographies stem out of inappropriate infrastructure, low education, and institutional factors. The absence of multi-sectoral and productive economic opportunities also poses an adverse impact on the resilience of households in rural areas. The women and households headed by females are found relatively more vulnerable than male-headed households.

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817.
Huang  Yuk Feng  Ahmed  Ali Najah  Ng  Jing Lin  Tan  Kok Weng  Kumar  Pavitra  El-Shafie  Ahmed 《Natural Hazards》2022,112(2):1423-1475
Natural Hazards - The lower number of rainfall events resulting in drier environment over the years is a crucial phenomenon attracting the concern of all around the world. The impact of rainfall...  相似文献   
818.
The Eastern Desert of Egypt suffered a protracted period of deformation triggered by cratonization of the new juvenile crust known as the Arabian Nubian Shield (ANS), which has been proposed for potential gold discoveries associated with the corresponding tectonic event. The Fatira area, on the border of Egypt''s Northern and Central Eastern Deserts, is covered with metavolcanic rocks twisted by a dextral relocation of the Fatira Shear Zone (FSZ) relative to the Barud magmatic body. The recent study evaluated many deformed post-orogenic granitic intrusions and felsite dikes associated with promising mineralization localities, notably orogenic gold deposits. The combination of various field observations and remote sensing data, followed by the analysis of aeromagnetic enhanced maps, allowed the differentiation of distinct lithologies, structural features, and hydrothermal alterations in the study area. Additionally, the integrated results obtained from the different interpretation techniques are utilized to identify and confirm the previously supposed mineralized localities in the Fatira and Abu Zawal areas and predict other matched localities. The final ASTER, Sentinel 2 hydrothermal alteration, and orientation entropy heat maps demonstrate the association between these mineralized regions and major structures related to the FSZ late stage of deformation rather than other structures studied throughout the area of interest.  相似文献   
819.
820.
The purpose of this paper is to analyse the development and the evolution of the fracture process zone during fracture and damage in quasi‐brittle materials. A model taking into account the material details at the mesoscale is used to describe the failure process at the scale of the heterogeneities. This model is used to compute histograms of the relative distances between damaged points. These numerical results are compared with experimental data, where the damage evolution is monitored using acoustic emissions. Histograms of the relative distances between damage events in the numerical calculations and acoustic events in the experiments exhibit good agreement. It is shown that the mesoscale model provides relevant information from the point of view of both global responses and the local failure process. © 2015 The Authors. International Journal for Numerical and Analytical Methods in Geomechanics published by John Wiley & Sons Ltd.  相似文献   
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