多尺度表达中线状要素的综合不确定性评价模型

在考虑节点化简的基础上建立了节点数据不确定性评价模型,基于曲线光滑模型建立了线元模型不确定性评价模型,在此基础上,根据不确定性传播律构建了由数据不确定性和模型不确定性合成的线状要素多尺度表达不确定性的综合评价模型。实验表明,综合不确定性指标值作为线状要素多尺度表达不确定性的量化指标是有效的。可将其用于计算线元不确定带的宽度,解决线状要素多尺度表达不确定性空间分析和推理问题;并用于线状要素多尺度表达的质量评价与控制。     

New interpretation of the Franciscan mélange at San Simeon coast,California: tectonic intrusion into an accretionary prism

Many concepts and interpretations on the formation of the Franciscan mélange have been proposed on the basis of exposures at San Simeon, California. In this paper, we show the distribution of chaotic rocks, their internal structures and textures, and the interrelationship between the chaotic rocks and the surrounding sandstones (turbidites). Mélange components, particularly blueschists, oceanic rocks, including greenstone, pillow lava, bedded chert, limestone, sandstone, and conglomerate, have all been brecciated by retrograde deformation. The Cambria Slab, long interpreted as a trench slope basin, is also strongly deformed by fluidization, brecciation, isoclinal folding, and thrusting, leading us to a new interpretation that turbiditic rocks (including the Cambria Slab) represent trench deposits rather than slope basin sediments. These rocks form an accretionary prism above mélanges that were diapirically emplaced into these rocks first along sinistral-thrust faults, and then along dextral-normal faults. Riedel shear systems are observed in several orders of scale in both stages. Although the exhumation of the blueschist blocks is still controversial, the common extensional fractures and brecciation in most of the blocks in the mélanges and further mixture of various lithologies into one block with mélange muddy matrix indicate that once deeply buried blocks were exhumed from considerable depths to the accretionary prism body, before being diapirically intruded with their host mélange along thrust and normal faults, during which retrograde deformation occurred together with retrograde metamorphism. Recent similar examples of high-pressure rock exhumation have been documented along the Sofugan Tectonic Line in the Izu forearc areas, in the Mineoka belt in the Boso Peninsula, and as part of accretionary prism development in the Nankai and Sagami troughs of Japan. These modern analogues provide actively forming examples of the lithological and deformational features that characterize the Franciscan mélange processes.     

Tectonic control of accommodation space and sediment supply within the Mata Amarilla Formation (lower Upper Cretaceous) Patagonia,Argentina

The Mata Amarilla Formation dates from the early Upper Cretaceous and was deposited during a transition in tectonic regime from the extensional Rocas Verdes Basin to the Austral Foreland Basin. Detailed sedimentological logs and architectural parameters were used to define 13 facies associations. The distribution of facies associations and associated variations in fluvial architecture have enabled large‐scale changes in accommodation space/sediment supply ratios (A/S ratio) to be defined for the three component sections of the Mata Amarilla Formation. The lower and upper sections are characterized by a high A/S ratio, whereas the middle section corresponds to a low A/S ratio. In the western part of the study area, small‐scale variations in the A/S ratio were recognized in the middle section. The strong west to east trend in evolution of the fluvial systems coincides with the direction of propagation of the Patagonian fold and thrust belt, which is located to the west of the study area. Intervals of high A/S ratio (i.e. lower and upper sections) are interpreted to have developed during periods of increased loading by the fold and thrust belt caused by tectonic uplift. In contrast, intervals of low A/S ratio (i.e. middle section) were developed during periods of tectonic quiescence. This article suggests that the large‐scale variations in A/S ratios are related to different rates of migration and growth of the Patagonian fold and thrust belt, whereas the small‐scale variation occurred in response to specific periods of thrusting and folding in the Patagonian fold and thrust belt (i.e. local loads). This field example of the effects of different scales of variation in A/S ratios across the Austral Foreland Basin could be used to recognize similar tectonically forced variations in stratigraphic architecture in other foreland basins throughout the world, as well as to understand the response of fluvial systems to such changes.     

Displacement transfer from fault-bend to fault-propagation fold geometry: An example from the Himalayan thrust front

The leading edge of the ENE-trending Himalayan thrust front in Pakistan exhibits along-strike changes in deformational style, ranging from fault-bend to fault-propagation folds. Although the structural geometry is very gently deformed throughout the Salt Range, it becomes progressively more complex to the east as the leading edge of the emergent Salt Range Thrust becomes blind. Surface geology, seismic reflection, petroleum well, and chronostratigraphic data are synthesized to produce a 3-D kinematic model that reconciles the contrasting structural geometries along this part of the Himalayan thrust front. We propose a model whereby displacement was transferred, across a newly-identified lateral ramp, from a fault-bend fold in the west to fault-propagation folds in the east and comparable shortening was synchronously accommodated by two fundamentally different mechanisms: translation vs. telescoping. However, substantially different shortening distribution patterns within these structurally contrasting segments require a tear fault, which later is reactivated as a thrust fault. The present geometry of this S-shaped displacement transfer zone is a combined result of the NW–SE compression of the lateral culmination wall and associated tear fault, and their subsequent modification due to mobilization of underlying ductile salt.     

基于ETM~+数据和GIS技术的缅甸铜金矿成矿预测

在利用遥感数据和地理信息系统(GIS)技术的矿产资源勘查与评价中,矿化蚀变信息提取和构造信息提取起着至关重要的作用。以缅甸铜金矿为例,利用ETM+遥感图像,采用比值法、阈值分割和主成分分析(PCA)提取羟基蚀变信息;利用数字高程模型和遥感数据提取与铜金矿化有关的线环构造,结合地质资料和上述信息,利用证据权和分形方法进行整合,确定该研究区的成矿远景区。结果发现,已知铜金矿均分布于成矿靶区中,综合信息可为下一步的矿产资源勘探工作提供决策依据。     

基于MonoRTM模型的微波辐射计反演方法研究

基于辐射传输模型MonoRTM计算天空亮温度,使用多元线性统计回归方法和BP神经网络方法分别对大气温度和水汽密度廓线进行了反演,检验并分析了两种方法的反演精度.结果表明,多元线性回归方法反演的温度偏差总体不大于6K,反演的水汽密度偏差小于4 g/m3;神经网络方法反演的温度偏差小于2K,反演的水汽密度误差总体不大于2 g/m3.与探空数据的对比表明,对于大气温度和水汽密度反演,BP神经网络方法的反演结果都要比多元线性回归方法的反演结果更接近探空资料值.     

Ekman层风速随高度分布方程的数值解试验

根据大气水平运动方程推导出Ekman层风速随高度分布方程,该分布可用二阶线性微分方程表示,用有限差分法求解该二阶线性微分方程的边值问题的数值解,并给出计算程序,输出结果。将结果与经典解析解比较,讨论了经典解的正确性和适用范围。     

地层剖面计算表的计算机自动处理

地层剖面计算表的计算机自动处理 ,涉及剖面是由老地层向新地层测制还是由新地层向老地层测制、褶皱的识别处理、存在回测时 (特别是在回测中又存在背向斜时 )的处理、测段厚度及分层厚度的计算等几个主要环节。文章引入剖面方向系数 η、测段方向系数κ、回测系数 ρ 3个新参数 ,建立了地层剖面计算表自动处理的数学模型 ,可以非常方便地将剖面图及其柱状图以矢量格式输出     

Effect of soil interaction on the performance of liquid column dampers for seismic applications

The effects of soil–structure interaction (SSI) while designing the liquid column damper (LCD) for seismic vibration control of structures have been presented in this study. The formulation for the input–output relation of a flexible‐base structure with attached LCD has been presented. The superstructure has been modelled by a single‐degree‐of‐freedom (SDOF) system. The non‐linearity in the orifice damping of the LCD has been replaced by equivalent linear viscous damping by using equivalent linearization technique. The force–deformation relationships and damping characteristics of the foundation have been described by complex valued impedance functions. Through a numerical stochastic study in the frequency domain, the various aspects of SSI on the functioning of the LCD have been illustrated. A simpler approach for studying the LCD performance considering SSI, using an equivalent SDOF model for the soil–structure system available in literature by Wolf (Dynamic Soil–Structure Interaction. International Series in Civil Engineering and Engineering Mechanics. Prentice‐Hall: Englewood Cliffs, NJ, 1985) has also been presented. Copyright © 2005 John Wiley & Sons, Ltd.