Morphotectonic evaluation of the Delhi region in northern India,and its significance in environmental management     

B.?L.?Kaul  M.?K.?PanditEmail author 《Environmental Geology》2004,46(8):1118-1122

This paper deals with the morphotectonic evaluation of the Delhi region in northern India to understand its impact on land use and urban development. To accommodate heavy urbanization and population rise (being the capital of India), the area has undergone tremendous environmental degradation resulting from a mismatch between adopted land use and morphotectonic considerations. The geomorphic and drainage signatures of the region have evolved out of interaction of varied geological parameters including neotectonic activities. We have evaluated the changes in the drainage pattern of the Yamuna River in the Delhi region to underline its significance in geomorphic evolution and subsequent land use and/or land suitability. The Yamuna River has shown variations both in channel position and geometry over the last two centuries. The observed migration pattern of the river (shifting of confluences, position and disposition of palaeochannels, etc.,) cannot be attributed to normal river phenomenon and appears to have been effected by neotectonic changes. In addition, some case studies are discussed to underline the significance of geomorphic factors in urban development.  相似文献   

A simplified method for simulation of strong ground motion using finite rupture model of the earthquake source     

A.?JoshiEmail author  S.?Midorikawa 《Journal of Seismology》2004,8(4):467-484

We present a simplified method to simulate strong ground motion for a realistic representation of a finite earthquake source burried in a layered earth. This method is based on the stochastic simulation method of Boore (Boore, D. M., 1983, Bull. Seism. Soc. Am. 73, 1865–1894) and the Empirical Greens Function (EFG) method of Irikura (Irikura, K., 1986, Proceedings of the 7th Japan Earthquake symposium, pp. 151–156). The rupture responsible for an earthquake is represented by several subfaults. The geometry of subfaults and their number is decided by the similarity relationships. For simulation of ground motion using the stochastic simulation technique we used the shapping window based on the kinetic source model of the rupture plane. The shaping window deepens on the geometry of the earthquake source and the propagation characteristics of the energy released by various subfaults. The division of large fault into small subfaults and the method for accounting their contribution at the surface is identical to the EGF. The shapping window has been modified to take into account the effect of the transmission of energy released form the finite fault at various boundaries of the layered earth model above the source. In the present method we have applied the correction factor to adjust slip time function of small and large earthquakes. The correction factor is used to simulate strong motion records having basic spectral shape of ² source model in broad frequency range. To test this method we have used the strong motion data of the Geiyo earthquake of 24th March 2001, Japan recorded by KiK network. The source of this earthquake is modelled by a simple rectangular rupture of size 24 × 15 km, burried at a depth of 31 km in a multilayered earth model. This rupture plane is divided into 16 rectangular subfaults of size 6.0 × 3.75 km each. Strong motion records at eight selected near-field stations were simulated and compared with the observed records in terms of the acceleration and velocity records and their response spectrum. The comparison confirms the suitability of proposed rupture model responsible for this earthquake and the efficacy of the approach in predicting the strong motion scenario of earthquakes in the subduction zone. Using the same rupture model of the Geiyo earthquake, we compared the simulated records from our and the EGF techniques at one near-field station. The comparison shows that this technique gives records which matches in a wide frequency range and that too from simple and easily accessible parameters of burried rupture.  相似文献   

A multiphysics and multiscale software environment for modeling astrophysical systems     

Simon Portegies Zwart  Steve McMillan  Stefan Harfst  Derek Groen  Michiko Fujii  Breanndán Ó Nualláin  Evert Glebbeek  Douglas Heggie  James Lombardi  Piet Hut  Vangelis Angelou  Sambaran Banerjee  Houria Belkus  Tassos Fragos  John Fregeau  Evghenii Gaburov  Rob Izzard  Mario Jurić  Stephen Justham  Andrea Sottoriva  Marcel Zemp 《New Astronomy》2009,14(4):369-378

We present MUSE, a software framework for combining existing computational tools for different astrophysical domains into a single multiphysics, multiscale application. MUSE facilitates the coupling of existing codes written in different languages by providing inter-language tools and by specifying an interface between each module and the framework that represents a balance between generality and computational efficiency. This approach allows scientists to use combinations of codes to solve highly coupled problems without the need to write new codes for other domains or significantly alter their existing codes. MUSE currently incorporates the domains of stellar dynamics, stellar evolution and stellar hydrodynamics for studying generalized stellar systems. We have now reached a “Noah’s Ark” milestone, with (at least) two available numerical solvers for each domain. MUSE can treat multiscale and multiphysics systems in which the time- and size-scales are well separated, like simulating the evolution of planetary systems, small stellar associations, dense stellar clusters, galaxies and galactic nuclei. In this paper we describe three examples calculated using MUSE: the merger of two galaxies, the merger of two evolving stars, and a hybrid N-body simulation. In addition, we demonstrate an implementation of MUSE on a distributed computer which may also include special-purpose hardware, such as GRAPEs or GPUs, to accelerate computations. The current MUSE code base is publicly available as open source at http://muse.li.  相似文献   

山东东营凹陷古近系碎屑岩储层特征及控制因素   总被引：25，自引：10，他引：15       下载免费PDF全文

张琴  朱筱敏  钟大康  宋刚 《古地理学报》2004,6(4):493-502

通过对大量储层物性数据的分析和整理,结合薄片观察和扫描电镜分析结果,研究了不同构造背景、不同沉积类型及不同埋深的储层物性特征及其控制因素。东营凹陷近系碎屑岩储层类型多样,大多形成在冲积扇-河流、扇三角洲、近岸水下扇、深水浊积扇、三角洲前缘滑塌浊积扇以及滨浅湖滩坝等多种沉积环境中。碎屑岩储层类型主要包括砾岩、含砾砂岩、中粗砂岩、细砂岩及粉砂岩。其中中砂岩和细砂岩是最好的储层。但是不同地区、不同类型储层物性存在较大的差异。物性最好的储层为河道、（扇）三角洲前缘水下分流河道及河口坝砂体。在相同深度条件下,中央隆起带的物性最好,北部和南部次之。另外,本区随埋藏深度增加,碎屑岩储层物性逐渐变差（剔除次生孔隙的影响）。根据碎屑岩储层物性差异性分析和储层成岩演化研究结果,其储层物性主要受压实作用、碳酸盐溶蚀与胶结作用及沉积条件四大因素控制,其中压实作用、溶蚀作用及胶结作用是主要控制因素,而沉积条件对物性的影响主要表现在控制原生孔隙的发育程度,并进一步控制溶蚀、胶结等成岩作用。  相似文献   

27‐day variations of solar indices and cosmic ray neutron monitor intensities     

M. Minarovjech  V. Ru&#x;in  M. Saniga 《Astronomische Nachrichten》2008,329(1):20-25

Solar activity indices (coronal, chromospheric as well as photospheric) and cosmic ray neutron monitor rates (different cut‐off rigidity) have been used to study 27‐day variations in the years from 1957 to 2004. Daily data were employed for this purpose, analysed by the FFT and wavelet techniques. To work with a continuous data set for the cosmic rays (CR), the ‘Composite Cosmic Ray’ (CCR) set was first created from the observations carried out at different neutron monitor stations. The CCR frequency analysis shows significant 27‐day variations in the intensity of CR, with its amplitude's values very sensitive to the sign of the quantity qA. The most significant 27‐day variations of CR were found not to correlate with those of other solar indices. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Distribution Characteristics of Effective Source Rocks and Their Control on Hydrocarbon Accumulation: A Case Study from the Dongying Sag, Eastern China   总被引：10，自引：2，他引：8  

ZHU Guangyou  JIN Qiang  ZHANG Shuichang  DAI Jinxing  ZHANG Linye  LI Jian Research Institute of Petroleum Exploration  Development  China National Petroleum Corporation  Beijing  E-mail: zhugy Faculty of Geo-resource  Information  University of Petroleum  Dongying  Shandong Geo-science Academy in Shengli Oil Fiel  Dongying  Shandong 《《地质学报》英文版》2004,78(6):1275-1288

The exploration conducted in the Bohai Bay basin, eastern China has demonstrated that the abundant petroleum resources have close affinities to the hydrocarbon kitchen with rich organic matter. A number of oil-generating associations with various characteristics of organic geochemistry and assemblages of multiple reservoir facies are developed due to the multi-center sedimentation, multi-source supply and multi-cycle evolution of filling, which have resulted in the formation of multiple oil and gas accumulation zones of various layers and trap styles. Among them the Paleogene Shahejie Formation is the most important hydrocarbon accumulation combination in the Dongying sag. Heretofore, its proved reserve has reached nearly 1.8×109t, which accounts for more than 90% of the total proved reserves of the Dongying sag. Based on previous studies, more than 600 source rock samples and 186 crude oil samples of the Shahejie Formation, collected from 30 oilfields, have been treated with organic geochemical testing  相似文献   

Deriving the unitgraph without using rainfall data     

R. J. De Laine  Senior Lecturer 《Journal of Hydrology》1970,10(4):379-390

The characteristic of a linear time invariant system can be found uniquely from any two outputs that have no error: it is not necessary to know the inputs or the time duration of the system response. In hydrologic terms, the unitgraph of a catchment with linear characteristics may be found from records of runoff vs time.  相似文献   

Evaluation of NCEP TIGGE short-range forecast for Indian summer monsoon intraseasonal oscillation     

Snehlata?Tirkey  P.?MukhopadhyayEmail author 《Theoretical and Applied Climatology》2017,128(3-4):745-759

Potential evapotranspiration (PET) is one of the most critical parameters in the research on agro-ecological systems. The computational methods for the estimation of PET vary in data demands from very simple (empirically based), requiring only information based on air temperatures, to complex ones (more physically based) that require data on radiation, relative humidity, wind speed, etc. The current research is focused on three study areas in Greece that face different climatic conditions due to their location. Twelve PET formulae were used, analyzed and inter-compared in terms of their sensitivity regarding their input coefficients for the Ardas River basin in north-eastern Greece, Sperchios River basin in Central Greece and Geropotamos River basin in South Greece. The aim was to compare all the methods and conclude to which empirical PET method(s) better represent the PET results in each area and thus should be adopted and used each time and which factors influence the results in each case. The results indicated that for the areas that face Mediterranean climatic conditions, the most appropriate method for the estimation of PET was the temperature-based, Hamon’s second version (PET_Ham2). Furthermore, the PET_Ham2 was able to estimate PET almost similarly to the average results of the 12 equations. For the Ardas River basin, the results indicated that both PET_Ham2 and PET_Ham1 can be used to estimate PET satisfactorily. Moreover, the temperature-based equations have proven to produce better results, followed by the radiation-based equations. Finally, PET_ASCE, which is the most commonly used PET equation, can also be applied occasionally in order to provide satisfactory results.  相似文献   

新疆荒漠化现状、成因及对策   总被引：19，自引：2，他引：17  

田长彦  宋郁东  胡明芳 《中国沙漠》1999

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青海省气候异常偏暖的成因分析   总被引：3，自引：1，他引：2  

时兴合  赵燕宁  秦宁生 《中国沙漠》1999

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