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351.
A gravity survey on the scale of 1: 250 000 was carried out in Block L2 located in the Lamu basin of south‐east Kenya in order to study tectonic features and find out favourable petroleum prospects in the block. This paper, through data processing and synthetic interpretation of the measured gravity data in the block, discusses characteristics of the gravity field and their geological implications, determines the fault system and the basement depth, analyses features of the main strata, divides structure units and predicts favourable petroleum zones. In the block, the regional gravity anomaly is mainly caused by the inclined Moho surface that rises in the east and subsides in the west topographically and the Bouguer gravity anomaly primarily reflects the superimposition of the gravity effect derived from the Moho surface and the basement relief. Two groups of faults extending NW (NWW) and NE (NEE) respectively are dominant in the block and their activities resulted in the framework of east‐west zoning and south‐north blocking. The basement depth greatly changes in an alternative high and low pattern. The Permian‐Triassic, Jurassic and Tertiary strata are extensively developed, while the Cretaceous is only developed in the east of the block. Structurally, the block can be divided into five units, of which the Tana sag shows excellent source‐reservoir‐seal associations and is a favourable target for future petroleum exploration. 相似文献
352.
Shear wave velocity is one of the important dynamic characteristics of soil layers and applied widely in aseismic engineering. In this paper, 500 drill logging data are used to make a linear interpolation based on 0.01°×0.01°×1m grid. A shallow 3-D shear wave velocity structure of Tianjin coastal area is obtained. According to the data and geological background, we selected two typical velocity profiles to try to introduce and explain its relationship to basement structure. The results show that the shear wave velocity structure clearly presents the characteristic of stratification and lateral inhomogeneity. Furthermore, the difference of the shear wave structure between tectonic elements is clear and the velocity structure between the two sides of the local or border fault in the Quaternary is disturbed or affected significantly. It intuitively shows that the basement structure and fault activity of this region had good control of sedimentation development and strata formation in the Quaternary period which would have an important effect on engineering seismic and geological condition evaluation. 相似文献
353.
Located at the west of the Linfen basin, the Luoyunshan piedmont fault zone controls the western boundary of the basin. According to the measurements of the terraces in eight gullies along the Luoyunshan fault zone, five levels of terraces, namely T1~T5 have developed in these gullies. The heights of terraces T1, T2, T3, T4 and T5 are about 3m, 8~10m, about 20m, about 30m and 40~50m, respectively. The dating data of the terraces and investigation of the faulted landforms show that the Luoyunshan fault zone has experienced much activity since the Late Quaternary. The uplift rate of the terraces was 0.41mm/a since the Middle-Late Pleistocene, and 0.75mm/a since the Holocene. The increasing trend of uplift rate of the terraces along the Luoyunshan fault zone from the Middle-Late Pleistocene to Holocene indicates the tendency of gradual tectonic uplift of the fault zone since the late Quaternary. This is in good agreement with the increasing trend of subsidence rate of the Linfen basin from the Late Pleistocene to Holocene. 相似文献
354.
2009年云南姚安6.0级地震震源机制与发震构造的分析研究 总被引:1,自引:0,他引:1
利用P波、SV波、SH波初动及其振幅比联合反演震源机制解的方法,计算了2009年7月9日发生在云南姚安6.0级地震余震序列的震源机制解,同时结合地震序列的空间分布,对姚安6.0级地震的发震断层性质和震区应力场特征进行综合分析。结果分析表明:(1)姚安6.0级地震发震断层为NWW—SEE向的直立右旋走滑断层,与美国哈佛大学的主震CMT解节面基本一致,也与余震优势方向分布一致,证明结果可靠;(2)震区主压应力场优势方向为NNW—SSE向,与其现今区域构造应力场主压应力NNW—SSE向一致,表明主震应力场主要受到现今区域构造应力场的控制,同时还有一些小的余震与主震应力场不同,表明震区应力场的多样性和复杂性;(3)结合本次地震序列的空间分布、震源机制解特征、震区断裂构造特征综合分析,综合判定姚安6.0级地震的发震构造属于马尾箐断裂。 相似文献
355.
356.
基于SilverLight和REST的富网络地理信息系统框架设计 总被引:1,自引:0,他引:1
在WebGIS的快速发展过程中,其架构方法和实现技术的研究一直是人们关注的热点。本文针对传统WebGIS开发复杂度高、交互体验性贫乏、运行效率低等不足,在对RIA/SilverLight和REST技术的研究基础上,以整体结构模块化,开发行为统一化,代码可复用及经验可复用的指导思路下,提出由空间数据服务器(数据访问层DAL)、GIS服务和Web服务服务器(业务逻辑层BLL)及部署有SilverLight插件的浏览器(表现层UI)组成的3层架构式富网络地理信息系统,并阐述了数据层中空间属性数据库的设计和建立步骤以及优化经验,分析了业务逻辑层的构成和运行机制,为提高系统开发效率使用MVVM(Model-View-View Model,模型-视图-视图模型)设计模式,将表现层分为前端用户界面和后台逻辑两部分,并描述了用户熟悉的Office Ribbon设计样式的开发方法,说明了后台逻辑架构组件各自功能及通讯路径。最后,为验证此框架能够有效提高系统开发效率、丰富用户体验和改善系统运行性能表现等优势,利用SilverLight(C#)实现了应用实例——LightGIS。系统开发和运行实验表明,该框架能够很好地达成以下目的:(1)实现优美的用户操作界面和丰富的互操作性体验;(2)提供平滑、流畅的地图服务和高响应性空间分析;(3)具备优秀的系统可扩展潜力和可配置性。 相似文献
357.
国家主体功能区空间型监测评价指标体系 总被引:3,自引:1,他引:2
对国家主体功能区开展监测和评估是掌握主体功能区规划落实情况、动态监管主体功能区运行状态的基本途径。本研究首先提出了国家主体功能区空间型监测评价指标体系概念,继而分析了指标遴选原则,即体现国家主体功能区核心功能、具备较强空间展示能力、满足管理基本需要,以及指标的可操作性、综合性与独立性等要求。在此基础上,建立了包括9个指标组和60个具体指标的体系框架。具体为:监测评价指标组包括资源、环境、生态、自然灾害、经济、人口社会、政策、交通和主体功能区运行等9个指标组;每个指标组内包含若干个可操作的具体指标。进而,还讨论了空间型监测评价指标体系的完备性与实用性、指标数据的获取方法、指标数据的空间化处理与表达等关键问题。 相似文献
358.
全球重要农业文化遗产(GIAHS)经济评估概念框架:以中国稻鱼共生系统为例(英文) 总被引:2,自引:1,他引:1
Sonja BERWECK Parviz KOOHAFKAN Mary Jane Ramos dela CRUZ 闵庆文 焦雯珺 孙业红 刘某承 《资源与生态学报(英文版)》2013,4(3):202-211
全球重要农业文化遗产(GIAHS)项目是2002年由联合国粮农组织(FAO)发起,旨在建立全球重要农业文化遗产及其有关的景观、生物多样性、知识和文化保护体系,并在世界范围内得到认可与保护,使之成为可持续管理的基础。农业文化遗产地往往被认为比非遗产地更具经济价值,但目前还没有经济学分析来证明这一点,也没有任何针对农业文化遗产地的复杂的经济性能标准来长期监测其经济功能。本研究的目的在于建立一个经济评价方法,可用于遗产地与非遗产地之间比较。为此,本文选择了成本效益分析(CBA)方法。鉴于数据可得性的限制,经济分析的框架应该包括分析的方向、假设和数据要求,由此指导未来对GIAHS的经济评价。本研究选择中国青田稻鱼共生系统作为案例,根据数据可得性并针对不同活动(旅游,国内和国际市场的销售产品)以及相似系统间比较进行计算。 相似文献
359.
360.
Eudald Maestro 《Journal of Paleolimnology》2008,40(4):1053-1078
A complete third-order tectono-sedimentary cycle filled the Vernet lacustrine piggyback basin during the late Eocene. The
depositional sequence can be subdivided into five units or systems tracts with distinct architectural frameworks, which developed
a progressive unconformity. Sedimentary infilling of the piggyback basin began with retrogradational alluvial fans and fluvio-alluvial
deposits being deposited, arranged in two thinning- and fining-upward cycles during the uplifting and emplacement of the southernmost
Pyrenean thrusts, and with three thickening- and coarsening-upward progradational floodplain and lacustrine cycles, during
the quiescence of the southernmost thrusts, at the same time as the emplacement of several northernmost thrusts of the southern
Pyrenees. The facies associations identified represent different depositional environments in a sheetflow-dominated system,
including playa-lake deposits, floodplain deposits, sheetflow fluvial deposits and sheet deltas in ephemeral to shallow lacustrine
settings. Fourth and fifth order arid/semi-arid climatic cycles can be recognized, driven either by orbital obliquity and
precessional forcing (Milankovitch cyclicity), insolation cycles or possibly subprecessional autogenic mechanisms related
to the emplacement of northern thrusts and the consequent changes in the drainage basin. Arid periods are recorded by sheetflood
fluvial, ephemeral lacustrine or terminal splay deposits, with abundant medium-to-coarse-grained sandstone packages in red-to-grey
mudstones, a product of unconfined or low-confined sheetflows or hyperconcentrated flows, with bedload and suspended load,
during flood episodes, at times of lake lowstand. Semi-arid periods are recorded as relative highstand lacustrine deposits,
including grey-to-white mudstones deposited in prodelta environments and fine-grained sheet sandstone units sedimented in
a delta front (with minor channels and extensive sheet lobes) and prodelta environments in shallow lakes, from sheetflood
events. 相似文献