Diffusive wave solutions for open channel flows with uniform and concentrated lateral inflow     

P. Fan  J.C. Li 《Advances in water resources》2006

The diffusive wave equation with inhomogeneous terms representing hydraulics with uniform or concentrated lateral inflow into a river is theoretically investigated in the current paper. All the solutions have been systematically expressed in a unified form in terms of response function or so called K-function. The integration of K-function obtained by using Laplace transform becomes S-function, which is examined in detail to improve the understanding of flood routing characters. The backwater effects usually resulting in the discharge reductions and water surface elevations upstream due to both the downstream boundary and lateral inflow are analyzed. With a pulse discharge in upstream boundary inflow, downstream boundary outflow and lateral inflow respectively, hydrographs of a channel are routed by using the S-functions. Moreover, the comparisons of hydrographs in infinite, semi-infinite and finite channels are pursued to exhibit the different backwater effects due to a concentrated lateral inflow for various channel types.  相似文献   

Modelling peak accelerations from earthquakes   总被引：1，自引：0，他引：1  

Debbie J. Dupuis  Joanna Mills Flemming 《地震工程与结构动力学》2006,35(8):969-987

This paper deals with the prediction of peak horizontal accelerations with emphasis on seismic risk and insurance concerns. Non‐linear mixed effects models are used to analyse well‐known earthquake data and the consequences of mis‐specifying assumptions on the error term are quantified. A robust fit of the usual model, using recently developed robust weighted maximum likelihood estimators, is presented. Outlying data are automatically identified and subsequently investigated. A more appropriate model accounting for the extreme value nature of the responses, is also developed and implemented. The implication on acceleration predictions is demonstrated. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

山东惠民凹陷古近系湖泊地震涌浪记录的新发现   总被引：4，自引：4，他引：4  

杨剑萍  王亚丽  查明  牟雪梅 《地质学报》2006,80(11):1715-1721

在陆相湖盆中,地震引起的各种作用力可以对各种先成沉积物进行改造而形成原地震积岩,同样地震可引发涌浪、浊流及碎屑流而形成地震涌浪沉积及震浊积岩.通过大量岩心观察描述和成像测井资料分析,首次提出惠民凹陷中央隆起带沙河街组含有丘状交错层理的碎屑岩与典型的原地震积岩(包括震裂岩、震褶岩、自碎屑角砾岩等)紧密共生,当属于地震作用引发涌浪的沉积产物.本区地震涌浪沉积中发育丘状及洼状层理、包卷层理、平行层理、块状层理、波痕、冲刷及截切面等沉积构造.根据沉积特征和分布位置,本区地震涌浪沉积划分为两种类型,即位于涌浪基面附近的含塑性泥砾的搅动型和涌浪基面与正常浪基面之间的回流型.垂向上地震涌浪沉积一般位于原地震积岩之上,震浊积岩之下,组成完整的原地震积岩—地震涌浪沉积—地震浊积岩序列或原地震积岩—地震涌浪沉积序列.本区地震涌浪沉积的发现和研究,将为地质学家识别陆相湖盆地震事件沉积提供对比标准.  相似文献   

Constraining P-wave velocity variations in the upper mantle beneath Southeast Asia     

Chang Li  Robert D. van der Hilst  M. Nafi Toksöz 《Physics of the Earth and Planetary Interiors》2006,154(2):180-195

We have produced a P-wave model of the upper mantle beneath Southeast (SE) Asia from reprocessed short period International Seismological Centre (ISC) P and pP data, short period P data of the Annual Bulletin of Chinese Earthquakes (ABCE), and long period PP-P data. We used 3D sensitivity kernels to combine the datasets, and mantle structure was parameterized with an irregular grid. In the best-sampled region our data resolve structure on scale lengths less than 150 km. The smearing of crustal anomalies to larger depths is reduced by a crustal correction using an a priori 3D model. Our tomographic inversions reveal high-velocity roots beneath the Archean Ordos Plateau, the Sichuan Basin, and other continental blocks in SE Asia. Beneath the Himalayan Block we detect high seismic velocities, which we associate with subduction of Indian lithospheric mantle. This structure is visible above the 410 km discontinuity and may not connect to the remnant of the Neo-Tethys oceanic slab in the lower mantle. Our images suggest that only the southwestern part of the Tibetan plateau is underlain by Indian lithosphere and, thus, that the upper mantle beneath northeastern Tibet is primarily of Asian origin. Our imaging also reveals a large-scale high-velocity structure in the transition zone beneath the Yangtze Craton, which could have been produced in multiple subduction episodes. The low P-wave velocities beneath the Hainan Island are most prominent in the upper mantle and transition zone; they may represent counter flow from the surrounding subduction zones, and may not be unrelated to processes beneath eastern Tibet.  相似文献   

Conceptual model about the interaction between El Ni(n)o/ Southern Oscillation and Quasi-Biennial Oscillation in far west equatorial Pacific     

LIU Qinyu  LIU Zhengyu  PAN Aijun 《中国科学D辑(英文版)》2006,49(8)

Interaction between the Quasi-Biennial Oscillation in far west equatorial Pacific (QBOWP) and the El Nino/Southern Oscillation (ENSO) is studied using a new conceptual model. In this conceptual model, the QBOWP effects on ENSO are achieved through two ways: (1) the oceanic Kelvin wave along equatorial Pacific, and (2) the Atmospheric Walker Circulation anomaly, while ENSO effects on QBOWP can be accomplished by the atmospheric Walker Circulation anomaly. Diagnosis analysis of the model results shows that the Atmospheric bridge (Walker circulation) plays a more important role in interaction between the ENSO and QBOWP than the oceanic bridge (oceanic Kelvin wave along equatorial Pacific); It is found that by the interaction of the ENSO and QBOWP, a free ENSO oscillation with 3-5 years period could be substituted by a oscillation with the quasi-biennial period, and the dominant period of SST anomaly and wind anomaly in the far west equatorial Pacific tends to be prolonged with enhanced ENSO forcing. Generally, the multi-period variability in the coupled Atmosphere-Ocean System in the Tropical Pacific can be achieved through the interaction between ENSO and QBOWP.  相似文献   

Improvement of Nakamura technique by singular spectrum analysis   总被引：1，自引：1，他引：1  

Roberto Carniel  Fausto Barazza  Paolo Pascolo 《Soil Dynamics and Earthquake Engineering》2006,26(1):55-63

In this work we investigate the application of the Singular Spectrum Analysis to improve Nakamura Technique. The SSA has a wide and multidisciplinary range of applications; it allows a time series to be decomposed into different components, e.g. the signal itself, as well as various noise components, which can be subsequently removed from the data. Removal of the minor component of the data can lead to significant improvements in the identification of the system. In this paper the use of SSA Technique allows to optimize the signal to noise ratio before computing the classical Nakamura spectral ratios. A number of typical applications are also presented.  相似文献   

西昆仑接收函数反演与构造解析   总被引：2，自引：0，他引：2       下载免费PDF全文

钱辉  许志琴  姜枚  宿和平 《中国地质》2006,33(2):309-316

中法合作布设的青藏高原西昆仑叶城-噶尔(狮泉河)天然地震探测剖面穿越了西昆仑构造的主要构造单元, 通过对36个台站128个远震P波事件的接收函数分析,取得了各台站的接收函数随方位角和震中距变化的趋势, 分析了变化趋势与地壳构造的关系。通过台站平均接收函数的反演拟合,取得了120km深度范围以上的横波速度分布,综合地质构造解释,发现康西瓦断裂地表倾斜渐变为直立并略向南拖曳的现象,塔里木前陆盆地沉积与逆冲构造有比较明显的显示,同时推测了盆地下的滑脱构造。班公湖-怒江断裂也有向北俯冲的显示,得出了印藏碰撞远距离效应在西昆仑受阻,应力通过地表次级断裂释放,同时形成盆地沉积的前陆构造模式。  相似文献   

2.5维各向异性介质中地震波场数值模拟     

武晔  李小凡  赵玉莲  李信富 《物探化探计算技术》2006,28(4):289-293

这里实现了在2.5维各向异性介质中地震波传播的数值模拟。首先从2.5维一阶速度-应力弹性各向异性波动方程出发,得出了该方程的拟谱法数值解法;然后通过对Marmousi速度模型进行数值模拟,表明了拟谱法的有效性;最后计算并分析了均匀和混合各向异性介质中波的传播快照和理论模拟的地震记录,进一步认识了波在各向异性介质中的传播规律。  相似文献   

中心回线瞬变电磁探测的一种快速解释方法   总被引：3，自引：0，他引：3  

郭文波  宋建平  韩俊明  曹捷  李正宇 《物探与化探》2006,30(2):154-157,161

分析了中心回线装置激发的电磁场在晚期与平面电磁波的传播特征,通过时-频转换将TEM数据转换成平面波场数据,构建了关于反射函数的M×N阶欠定方程组。用线性规划法解出反射函数序列q_m,大量模型的反演结果与理论值误差很小。以q_m为参数绘制出电磁响应时间剖面图,从而实现了TEM快速成像解释。成像剖面清楚地反映了断面的地电特征。实测资料的处理结果说明了方法的实用性。  相似文献   

相控误差法在少井区岩性分布研究中的应用     

唐华风  王璞珺  陈文礼  程日辉  刘万洙  张艳 《新疆地质》2006,24(4):384-388

以塔里木盆地东北地区石炭系为例进行少井波阻抗反演,以此结果研究砂泥岩发育位置、剖面形态和厚度.波阻抗资料可分辨最小厚度为20 m,比常规剖面分辨率(30 m)高,可用于沉积相分析.但是用波阻抗资料进行泥岩视厚度计算,所得结果与钻井揭示厚度相比,相对误差为 12%~-15%.经过误差分析得知,相对误差与含泥率服从单峰态分布规律,且受沉积相控制.采用相控误差法校正泥岩视厚度得到真厚度,计算结果为勘探阶段烃源岩预测提供科学依据.  相似文献