尼泊尔8.1级地震对中国西藏地区造成的震害特征分析   总被引：1，自引：0，他引：1  

高锦瑞  尼玛  文升梁  张建龙 《震灾防御技术》2015,10(4):961-968

2015年4月25日尼泊尔发生8.1级地震,对我国西藏地区造成较大人员伤亡与房屋破坏,道路、通讯等生命线工程及水利等基础设施损坏严重。本文介绍了本次地震的基本情况,并在现场地震烈度调查和地震损失评估的基础上,对灾区震害进行了分析,给出了灾区房屋类别与破坏情况以及生命线系统与各行业的受损情况。通过分析此次地震的灾害特点,指出了灾区在抗震设防中存在的问题,并提出加大地震地质灾害的防治力度,科学编制恢复重建规划,加强防震减灾宣传,提高农牧民抗震设防意识,加强农牧区房屋建筑的指导和监管等建议,以减少地震造成的人员伤亡和财产损失,促进西藏地区经济和社会的和谐发展。  相似文献   

Groundwater vulnerability assessment in shallow aquifer of Kathmandu Valley using GIS-based DRASTIC model   总被引：1，自引：0，他引：1  

Dhundi Raj Pathak  Akira Hiratsuka  Isao Awata  Luonan Chen 《Environmental Geology》2009,57(7):1569-1578

In this paper, groundwater aquifer vulnerability map has been developed by incorporating the major geological and hydro-geological factors that affect and control the groundwater contamination using GIS based DRASTIC model. This work demonstrates the potential of GIS to derive a map by overlying various spatially referenced digital data layers that portrays cumulative aquifer sensitivity ratings across the Kathmandu Valley, Nepal, providing a relative indication of groundwater vulnerability to contamination. In fact, the groundwater is the major natural resources in Kathmandu for drinking purpose. The decline in groundwater levels due to the over exploitation and thus extracted water from shallow aquifer has been contaminated by the infiltration of pollutants from polluted river and land surface is continuous and serious. As the demand for water for human and industrial use has escalated and at the same time, the engineering and environmental costs are much higher for new water supplies than maintaining the existing sources already in use. Management of groundwater source and protecting its quality is therefore essential to increase efficient use of existing water supplies. Aquifer vulnerability maps developed in this study are valuable tools for environmental planning and predictive groundwater management. Further, a sensitivity analysis has been performed to evaluate the influence of single parameters on aquifer vulnerability assessment such that some subjectivity can be reduced to some extent and then new weights have been computed for each DRASTIC parameters.  相似文献   

Modelling the spatial distribution of present-day deformation in Nepal: how cylindrical is the Main Himalayan Thrust in Nepal?   总被引：1，自引：0，他引：1  

Antoine Berger  François Jouanne  Riad Hassani  Jean Louis Mugnier 《Geophysical Journal International》2004,156(1):94-114

  相似文献   

An evaluation of the inverted metamorphic gradient at Langtang National Park, Central Nepal Himalaya   总被引：5，自引：0，他引：5  

A. M. MACFARLANE 《Journal of Metamorphic Geology》1995,13(5):595-612

Abstract The crystalline core of the Himalayan orogen in the Langtang area of Nepal, located between the Annapurna-Manaslu region and the Everest region, contains middle to upper amphibolite grade pelitic gneisses and schists. These rocks are intimately associated with the Main Central Thrust (MCT), one of the major compressional structures in the northern Indian plate, which forms a 3.7-km-wide zone containing rocks of both footwall and hangingwall affinity. An inverted metamorphic gradient is noticeable from upper footwall through hangingwall rocks, where metamorphic conditions increase from garnet grade near the MCT zone to sillimanite + K-feldspar grade in the upper hangingwall. Petrographic data distinguish two metamorphic episodes that have affected the area: a high-pressure, moderate-temperature episode (M1) and a moderate-pressure, high-temperature episode (M2). Comparison with appropriate reaction boundaries suggests that conditions for M1 in the hangingwall were approximately 900–1200 MPa and 425–525°C. Thermobarometric results for 24 samples from the footwall, MCT zone and hangingwall reflect P-T conditions during the M2 phase of 400–1200 MPa and 490–660° C. The decrease in estimated palaeopressures from footwall to hangingwall approximate a lithostatic gradient of 27 MPa km^-1, with slight fluctuations in the MCT zone reflecting structural discontinuities. In contrast to the palaeopressures, palaeotemperatures are indistinguishable across the entire area sampled. Although field evidence suggests the presence of the inverted palaeothermal gradient well known in the Himalaya, quantitative thermobarometry indicates that temperatures of final equilibration were all within error of each other across 17 km of section. At Langtang, change in pressure is responsible for the presence of the sequence of index minerals through the section. I interpret these data to reflect diachronous attainment of equilibrium temperature conditions in a lithostatic palaeopressure profile after ductile faulting of the sequence.  相似文献   

Groundwater pollution by arsenic concentration in sedimentary aquifers in the Indo-Gangetic Basin of Nepal     

Sunil Kumar Dwivedi Pusker Raj Joshi Sanjiv Shrestha Yaga Raj Bhandari Ram Bhadur Sah 《中国地球化学学报》2006,25(B08):139-139

Naturally occurring arsenic （As） in groundwater of sedimentary aquifers has emerged as a global problem, and the Indo-Gangetic Basin of Nepal is no exception. In the sedimentary aquifers of the Indo-Gangetic Basin, arsenic enrichment and mobilization in groundwater by natural processes is considered an issue of major environmental health concern. About 11 million people, 47% of Nepali＇s total population living in the region and approximately 90% of them are relying on groundwater as their major source of drinking water. Moreover, 205555 ha of agricultural land in the basin are irrigated by groundwater through large numbers of deep and shallow irrigation tubewells for extensive cultivation of crops which has lead to creation of other pathways for arsenic ingestion among the people living in the region. It is estimated that around 0.5 million people in the basin are living at risk of arsenic poisoning In addition, some recent research shows the prevalence of dermatosis related to arsenicosis from 1.3% to 5.2 % and the accumulation of arsenic in biological samples like hair and nails much higher than the acceptance level. In these circumstances, the source of the natural arsenic concentration in groundwater of the Indo-Gangetic Basin is quite essential to explore. Therefore, to investigate the source of arsenic and management of arseniferious groundwater used for human consumption and irrigation, along with treatment or avoidance, is clearly an issue of research concern. Present research is carried out to understand the source of natural arsenic and its mobilization in groundwater of the Indo-Gangetic Basin. For this, we have collected bedrock, aquifer sediments and water samples from the study area. Sediment samples were taken from different lithofacies viz. clay, silt, sand and sandy gravels from groundwater aquifer where arsenic concentration is high. Water samples were taken from domestic shallow and deep tubewells in grid pattern. Bedrock samples were collected from source of the aquifer sediment, northern part of the Indo-Gangetic Basin, especially from the Siwalik and Lesser Himalaya. This paper particularly focuses on geology, mineralogy, hydro-geochemistry and sedimentary analysis of the high arsenic affected districts; Rautahat, Sarlahi, Parsa, and Kailali of Nepal.  相似文献   

Thermal evolution of the Lesser Himalaya, central Nepal: Insights from K-white micas compositional variation     

Lalu Prasad Paudel  Kazunori Arita 《Gondwana Research》2006,9(4):409-425

The Lesser Himalayan low- to medium-grade metamorphic rocks in central Nepal are rich in K-white micas occurring as porphyroclasts and in matrix defining S₁ and S₂. Porphyroclasts are usually zoned with celadonite-poor cores and celadonite-rich rims. The cores are the relics of igneous or high grade metamorphic muscovites, and the rims were re-equilibrated or overgrown under lower T metamorphic conditions. The matrix K-white micas defining S₁, pre-dating the Main Central Thrust activity, are generally celadonite-rich. They show heterogeneous compositional zoning with celadonite-rich cores and celadonite-poor rims. They were recrystallized at lower T condition prior to the Main Central Thrust activity, most probably prior to the India–Asia collision (pre-Himalayan metamorphism). The matrix K-white micas along S₂, synchronous to the Main Central Thrust activity (Neohimalayan metamorphism), are relatively celadonite-poor and were recrystallized under relatively higher T condition. K-white micas defining S₁ also were partially re-equilibrated during the Neohimalayan metamorphism. The average compositions of recrystallized K-white micas defining both S₁ and S₂ become gradually poor in (Fe + Mg)- and Si-contents and rich in Al- and Ti-contents from south to north showing an increase of metamorphic grade from structurally lower to higher parts in the Lesser Himalaya. This shows that the metamorphism is inverted throughout the inner Lesser Himalaya. The tectono-metamorphic significance of the published K–Ar and ⁴⁰Ar / ³⁹Ar K-white micas ages from the Lesser Himalaya need re-evaluation in the context of observed intrasample compositional variation and zoning, and possible higher closure temperature (500 °C) for K–Ar system.  相似文献   

尼泊尔M8.1地震震前卫星重力场时变特征     

邹正波  李辉  吴云龙  吴桂桔  康开轩 《大地测量与地球动力学》2015,35(4):547-551

利用多年GRACE卫星重力变化资料,给出尼泊尔及周缘地区的重力场时空变化,以探索2015-04-25尼泊尔M8.1地震震前重力变化特征;并基于球形位错理论,利用断层模型数据模拟同震重力场变化。研究表明,区域重力场变化以2008年为界存在明显的分时段特征,2003~2008年以重力增加为主,而2009~2014年以重力减少为主;且存在明显的分区性,区域重力场在尼泊尔地震震中四周呈正负相间分布;震前局部重力场变化在压缩区重力增加,拉张区重力减少,与理论同震重力变化结果一致。总结研究区域近年来M7.0以上地震震前重力变化特征发现,地震基本发生在重力变化高梯度带的过渡带及重力变化零值线附近。  相似文献   

Power interplay between actors: using material and ideational resources to shape local adaptation plans of action (LAPAs) in Nepal     

Sumit Vij  Robbert Biesbroek  Annemarie Groot  Katrien Termeer  Binod Prasad Parajuli 《Climate Policy》2019,19(5):571-584

Deliberation over how to adapt to short or long-term impacts of climate change takes place in a complex political setting, where actors’ interests and priorities shape the temporal dimension of adaptation plans, policies and actions. As actors interact to pursue their individual or collective interests, these struggles turn into dynamic power interplay. In this article, we aim to show how power interplay shapes local adaptation plans of action (LAPAs) in Nepal to be short-term and reactive. We use an interactional framing approach through interaction analyses and observations to analyse how actors use material and ideational resources to pursue their interests. Material and ideational resources that an actor deploys include political authority, knowledge of adaptation science and national/local policy-making processes, financial resources and strong relations with international non-governmental organizations and donor agencies. We find that facilitators and local politicians have a very prominent role in meetings relating to LAPAs, resulting in short-termism of LAPAs. Findings suggest that there is also a lack of female participation contributing to short-term orientated plans. We conclude that such power interplay analysis can help to investigate how decision making on the temporal aspects of climate adaptation policy takes place at the local level.

Key policy insights

• Short-termism of LAPAs is attributed to the power interplay between actors during the policy design process.

• Improved participation of the most vulnerable, especially women, can lead to the preparation of adaptation plans and strategies focusing on both the short and long-term.

• It is pertinent to consider power interplay in the design and planning of adaptation policy in order to create a level-playing field between actors for inclusive decision-making.

• Analysis of dynamic power interplay can help in investigating climate change adaptation controversies that are marked by uncertainties and ambiguities.

  相似文献   

The P-T-t-D evolution of the Mahabharat,east-central Nepal: The out-of-sequence development of the Himalaya     

《地学前缘(英文版)》2022,13(2):101057

A garnet-bearing schist from the southernmost such exposure along the Himalaya in east central Nepal records prograde metamorphism at 32.4 ?± ?0.3 ?Ma. Phase equilibria modelling, combined with Ti-in-biotite and quartz c-axis thermometry, outline a tight-to-hairpin pressure-temperature (P-T) path extending from ~515 ?°C and 5.5 ?kbar to peak conditions at ~575 ?°C and 7 ?kbar followed by deformation during the retrograde phase at 480–515 ?°C and 6–7 ?kbar. The new geochronology data place an upper bound on the evolution of metamorphism and deformation in the frontal-most part of the Himalaya, which lasted until 17.5 ?Ma, as indicated by previously published ⁴⁰Ar/³⁹Ar data. The P-T-time data from this part of the Himalaya, as well as that from more hinterland-ward portions of the orogen, outline a progressive, stepwise, commonly out-of-sequence evolution. Further data from along the orogen indicates that this evolution is not a local phenomenon, but instead characterizes the tectonics of this system as a whole.  相似文献   

Think globally,act locally: On the status of the threatened fauna in the Central Himalaya of Nepal     

《Geoforum》2015

The World Conservation Union (IUCN) publishes the Red List of Threatened Species, the most authoritative information available globally on the conservation status of species. However, the status of globally threatened species remains controversial at local levels because many of them are not protected as part of national statutory law. Such anomalies are examples of controversies in implementing the much-hyped environmental slogan “think globally, act locally”. Here we provide a comparative review between globally threatened species as listed by the IUCN Red List found in Nepal and those of nationally protected species under Nepalese law. We discovered a significantly higher diversity of globally threatened mammals and birds in Nepal than would be expected relative to their global ratios. We established remarkable disparities in species conservation in Nepal: (1) a large number (an average of 85% of species of five taxonomic groups: mammals, birds, amphibians, fishes and reptiles) of IUCN-listed globally threatened species found in Nepal are not protected by national law; (2) most protected species listed are mammals (70%), but more than half of globally-threatened mammals found in Nepal are not protected; and (3) amphibians and fish are not protected, although they represent 12% of the total number of globally-threatened species found in the country. Such large gaps in Nepalese conservation law are an indication of unresponsive and inefficient conservation planning. The Government of Nepal and international conservation partners should: (1) emphasize knowledge-based conservation strategies for all taxonomic groups; and (2) prioritize updating the lists of protected species.  相似文献