排序方式: 共有20条查询结果,搜索用时 15 毫秒
1.
AnalysisandstudyofthelargeearthquakeriskinYanqingHuailaibasinCHANGQUANLIU(刘昌铨)SHIXUJIA(嘉世旭)MINGJUNLIU(刘明军)CHANGFALI(李长发... 相似文献
2.
黄龙的景观是在数万年的岩溶地质作用下的产物。近年来黄龙钙华出现了干涸、变黑、沙化等现象严重地影响了景观的观赏性。水资源在黄龙钙华发展变化中起着重要的作用,笔者通过收集并分析黄龙地区的监测数据,针对监测系统不健全.时序数据缺乏的特点,选用对时序数据要求不高、预测效果较好的灰色系统模型,以岩溶水体的pH值为指标预测了钙华未来的发展情况。采用地质统计学空间分析的克里金插值法,对预测结果进行插值获得了整个景区的钙华预测结果。笔者按pH值将钙华演化情况划为强侵蚀、弱侵蚀、堆积3种类型,指出黄龙钙华景观目前正处于动态平衡与消亡重组阶段。 相似文献
3.
4.
鲁武马盆地古近系-新近系发育多套超深水、超大型、富含天然气藏的重力流沉积砂体。以始新统砂体为解剖对象,分析区内重力流砂岩储层特征及成因。结果表明砂体以巨厚层状产出于深海泥岩内部,并与周围泥岩截然接触,测井曲线表现出宏观均一性;岩心揭示此类巨厚砂体是由多期单砂体叠置而成,单砂体是由底部高密度颗粒流和顶部低密度浊流两部分组成,且经历过强底流改造。鲁武马河流三角洲强大物源供给决定了区内砂体分布面积和体积规模;深海滑塌、块体搬运等重力流沉积过程控制了沉积体粒序构造和内部结构;海底区域性强底流持续冲刷并携带走单砂体顶部细粒沉积物,残留了底部“干净”的中粗粒砂岩;多期沉积事件和频繁水道迁移决定了砂体纵、横向叠加展布,并最终形成了区内厚度巨大、岩性宏观均一且连通性极好的超大型深水重力流沉积砂岩储层。 相似文献
5.
在城市测量中,由于建筑物的不断增高,绿化植物的多样与浓密,仅仅利用GPS-RTK无法完成一项测量工作,必须与常规测量相结台才行.为此,本文采用GPS-RTK与边角交会联合测量图根控制;并介绍了GPS-RTK与常规的边角变会相结合测图根控制的施测、检核及计算方法,分析了交会点的点位精度;最后通过算例得出几点有用的结论. 相似文献
6.
7.
This paper discusses the origin and development of the Zhujiang Delta on the basis of the analyses of the fault systems, lithofacies, depositional thickness, ancient coastline and 14C dating. We consider that the delta is a multi-faulting block, whose external form, internal structure and configuration of its ancient coastline are all strictly controlled by three active sets of the NE, NW and WE faults. 相似文献
8.
推导出方向后交点住精度的显函数公式;用解析法导出对称交会时最佳交会角和最佳点精度;用无约束最优化共轭梯度法,求出一般情况下方向后交最佳交会角和点位精度;求出同一三角形三个内角分别作顶角进行后交定位的最佳点位,得出三角形内只有一个最佳点位的结论,给出一种选择近似最佳点位的方法. 相似文献
9.
陀螺经纬仪马达内部温升对摆动中值的影响 总被引:2,自引:0,他引:2
首先对陀螺经纬仪马达内部产生的温升进行了测定,其次实验了温升对摆动中值的影响,并进行了理论探讨,最后用直流马达进行了改进实验。 相似文献
10.
Tectonic transition from the Songpan-Garzê Fold Belt to the Sichuan Basin, south-western China 总被引:1,自引:0,他引:1
The formation of the Songpan-Garzê Fold Belt and the initiation of the terrestrial Sichuan Basin are related to closing of the Palaeo-Tethys during the Late Triassic Indosinian orogeny. The Songpan-Garzê Fold Belt is composed of Triassic (T1--T23) turbiditic deposits and Palaeozoic greywacke-shale, whereas the Sichuan Basin consists of Sinian to middle Upper Triassic (T23) platform carbonates and Upper Triassic (T3X to Quaternary terrestrial elastics. Three principal deformation episodes during the Late Triassic (Norian to Rhaetian) were progressively localized towards the south-eastern margin of the fold belt. D1 was a SW-directed shortening event, related to continuous subduction of the Palaeo-Tethys, and produced NW-trending structures. Differential strain between the fold belt and the Sichuan Basin was accommodated by sinistral shearing along a NE-trending transitional zone during D2. D3 SE-directed compression was the result of collision between the Cimmerian and Eurasian Continents and initiated the Longmen Mountains Thrust-Nappe Belt and terrestrial Sichuan Basin. Post-D3 deformation, related to SE-directed thrusting in the Longmen Mountains, then propagated from hinterland to foreland. The Indosinian orogeny closed the Palaeo-Tethys and terminated the marine conditions that dominated the early evolution of the intracratonic Sichuan Basin. Tectonic loading from the exhumed fold belt and Thrust-Nappe Belt induced substantial subsidence in the Sichuan Basin, especially in the Western Sichuan Foreland Basin, resulting in the deposition of a terrestrial clastic sequence during Late Triassic (T3X to Quaternary times. The foreland basin history comprises an early stage during the Late Triassic (T3x1–2), an over-fill stage during the latest Triassic to Early Cretaceous (T3X3- K1J), and a shrinking stage from the Late Cretaceous to the Quaternary (K2J-Q). These can be correlated with tectonic events in the Thrust-Nappe Belt. 相似文献