固体介质中弹性波传播机制的细胞自动机有限深势阱模型

分析了采用细胞自动机研究波动问题的建模方法，针对一维、均匀、各向同性固体介质中弹性纵波的微观机制，借用一经典弹簧振子模型、细胞自动机格子气模型，以及量子力学中的无限深势阱模型，建立了一个细胞自动机有限深势阱模型，从量子力学角度出发，基于介观物理和纳米概念，以微观精子的德布罗意假设为基础，利用薛定谔方程，讨论了该模型中粒子（分子组）的振动速度与粒子物质波波速之间的联系，给出了模型中的波动方程，得出ζ＝Vp（ζ为粒子振动速度，Vp为物质波纵波波速）。同时还讨论了模型中粒子的大小和能量传递问题，引入引力场，得出了能量及引力势的量子化条件，另外，对声波速度、格子气粒子振动速度和本文模型中分子组振动速度进行了比较；还对本文模型中的粒子能量分布作了分析。     

Contrasting rifted margin styles south of Greenland: implications for mantle plume dynamics

We present new and reprocessed seismic reflection data from the area where the southeast and southwest Greenland margins intersected to form a triple junction south of Greenland in the early Tertiary. During breakup at 56 Ma, thick igneous crust was accreted along the entire 1300-km-long southeast Greenland margin from the Greenland Iceland Ridge to, and possibly 100 km beyond, the triple junction into the Labrador Sea. However, highly extended and thin crust 250 km to the west of the triple junction suggests that magmatically starved crustal formation occurred on the southwest Greenland margin at the same time. Thus, a transition from a volcanic to a non-volcanic margin over only 100–200 km is observed. Magmatism related to the impact of the Iceland plume below the North Atlantic around 61 Ma is known from central-west and southeast Greenland. The new seismic data also suggest the presence of a small volcanic plateau of similar age close to the triple junction. The extent of initial plume-related volcanism inferred from these observations is explained by a model of lateral flow of plume material that is guided by relief at the base of the lithosphere. Plume mantle is channelled to great distances provided that significant melting does not take place. Melting causes cooling and dehydration of the plume mantle. The associated viscosity increase acts against lateral flow and restricts plume material to its point of entry into an actively spreading rift. We further suggest that thick Archaean lithosphere blocked direct flow of plume material into the magma-starved southwest Greenland margin while the plume was free to flow into the central west and east Greenland margins. The model is consistent with a plume layer that is only moderately hotter, 100–200°C, than ambient mantle temperature, and has a thickness comparable to lithospheric thickness variations, 50–100 km. Lithospheric architecture, the timing of continental rifting and viscosity changes due to melting of the plume material are therefore critical parameters for understanding the distribution of magmatism.     

A rifted inside corner massif on the Mid-Atlantic Ridge at 5°S

The structure of the Mid-Atlantic Ridge at 5°S was investigated during a recent cruise with the FS Meteor. A major dextral transform fault (hereafter the 5°S FZ) offsets the ridge left-laterally by 80 km. Just south of the transform and to the west of the median valley, the inside corner (IC – the region bounded by the ridge and the active transform) is marked by a major massif, characterized by a corrugated upper surface. Fossil IC massifs can also be identified further to the west. Unusually, a massif almost as high as the IC massif also characterizes the outside corner (OC) south of the inactive fracture zone and to the east of the median valley. This OC massif has axis-parallel dimensions identical to the IC massif and both are bounded on their sides closest to the spreading axis by abrupt, steep slopes. An axial volcanic ridge is well developed in the median valley both south of the IC/OC massifs and in an abandoned rift valley to the east of the OC massif, but is absent along the new ridge-axis segment between the IC and OC massifs. Wide-angle seismic data show that between the massifs, the crust of the median valley thins markedly towards the FZ. These observations are consistent with the formation of the OC massif by the rifting of an IC core complex and the development of a new spreading centre between the IC and OC massifs. The split IC massif presents an opportunity to study the internal structure of the footwall of a detachment fault, from the corrugated fault surface to deeper beneath the fault, without recourse to drilling. Preliminary dredging recovered gabbros from the scarp slope of the rifted IC massif, and serpentinites and gabbros from the intersection of this scarp with the corrugated surface. This is compatible with a concentration of serpentinites along the detachment surface, even where the massif internally is largely plutonic in nature.     

山东海阳断裂东石兰沟段晚更新世以来地表断错特征与最大潜在地震估计

海阳断裂是胶东半岛NE向牟平 -即墨断裂带东部一条规模较大的断裂 ,尽管晚更新世以来该断裂的地表断错活动总体上已基本停息 ,但东石兰沟段在晚更新世晚期以来仍有断错地表的活动。最后一次断错地表的活动发生在距今 3 7～ 1 2万年 ,但接近 1 2万年。地表破裂长度约6 5km ,活动段长度 8km。地表断错以走滑活动为主 ,可见最大倾滑位移 0 2m ;根据断层擦痕侧伏角推测最大水平位移 1 13m。最后一次断错地表的活动若以距今 1 2万年计算 ,则最大平均倾滑速率为 0 0 17mm/a ;最大平均右旋走滑速率为 0 0 94mm/a。野外观测到该活动段的断错活动表现为突发断错 ,根据地震地表破裂参数、活动段长度与地震的关系 ,估计其最大潜在地震为 6 级     

贡嘎山东坡亚高山森林区蒸散力的估算

以海螺沟 30 0 0m气象站的观测资料为基础 ,运用Penman公式法　空气饱和差法和桑斯维特公式法 ,计算了贡嘎山东坡亚高山林林的年平均蒸散力 ,其结果为分别为 431 81mm、171 4mm和 44 6 4mm。通过分析蒸散力的影响因素 ,对这三种计算蒸散力的方法作了比较 ,对计算结果存在的差异作了比较合理的解释 ,认为用Penman公式法可以估计出本研究区的蒸散力。同时 ,对蒸散力及其影响因自进行了相关分析 ,指出湿度和风不是速制约研究区蒸散力的主导因子 ,并分析了蒸散力与水面蒸发的关系 ,由此推导出估算蒸散力的简便方程 :PE =6 6 77 0 6 91E60 1 0 75 1ITm 0 0 396Pm。     

A general model for estimating actual evaporation from non-saturated surfaces

Based on energy balance equation and mass transfer equation, a general model to estimate actual evaporation from non-saturated surfaces was derived. Making use of two concepts, “relative evaporation” and “relative drying power”, a relationship was established to account for the departure from saturated conditions. Using this model, the actual evaporation (evapotranspiration) can be calculated without the need of potential evaporation estimation. Furthermore, the model requires only a few meteorological parameters that are readily and routinely obtainable at standard weather stations. Based on nearly 30 years data of 432 meteorological stations and 512 hydrological stations in China, in combined with GIS, nine typical river basins were selected. Using the data of the selected river basins, the model was tested. The results show that the actual evaporation rate can be estimated with an error of less than 10% in most areas of China, except few years in the Yellow River Basin.     

A study on the early-warning technique concerning debris flow disasters

According to the principle of the eruption of debris flows, the new torrent classification techniques are brought forward. The torrent there can be divided into 4 types such as the debris flow torrent with high destructive strength, the debris flow torrent, high sand-carrying capacity flush flood torrent and common flush flood by the techniques. In this paper, the classification indices system and the quantitative rating methods are presented. Based on torrent classification, debris flow torrent hazard zone mapping techniques by which the debris flow disaster early-warning object can be ascertained accurately are identified. The key techniques of building the debris flow disaster neural network (NN)real time forecasting model are given detailed explanations in this paper, including the determination of neural node at the input layer, the output layer and the implicit layer, the construction of knowledge source and the initial weight value and so on. With this technique, the debris flow disaster real-time forecasting neural network model is built according to the rainfall features of the historical debris flow disasters, which includes multiple rain factors such as rainfall of the disaster day, the rainfall of 15 days before the disaster day, the maximal rate of rainfall in one hour and ten minutes. It can forecast the probability, critical rainfall of eruption of the debris flows, through the real-time rainfall monitoring or weather forecasting. Based on the torrent classification and hazard zone mapping, combined with rainfall monitoring in the rainy season and real-time forecasting models, the debris flow disaster early-warning system is built. In this system, the GIS technique, the advanced international software and hardware are applied, which makes the system′s performance steady with good expansibility. The system is a visual information system that serves management and decision-making, which can facilitate timely inspect of the variation of the torrent type and hazardous zone, the torrent management, the early-warning of disasters and the disaster reduction and prevention.     

Tectonique transpressive en terre Adélie au Paléoprotérozoı̈que (Est Antarctique)Palaeoproterozoic transpression in Terre Adélie (East Antarctica)

The Palaeoproterozoic units of Terre Adélie show two types of structural domains associated with HT–LP metamorphic conditions: domes and NS–N340° striking vertical shear zones. Shear zones reflect dextral transpressive motions. Domes reflect sub-vertical shortening and principal stretching subparallel to shear zones. They could partly result from longitudinal flow coeval with transpression. Deformations are comparable to those described along the eastern and western boundaries of the Archean Gawler Craton (South-East Australia), which underlines the continuity between these two areas before opening of the Austral Ocean. To cite this article: A. Pelletier et al., C. R. Geoscience 334 (2002) 505–511.