Mapping landslide susceptibility from small datasets: A case study in the Pays de Herve (E Belgium)   总被引：3，自引：1，他引：3  

Alain Demoulin  Chang-Jo F. Chung 《Geomorphology》2007,89(3-4):391-404

A landslide susceptibility map is proposed for the Pays de Herve (E Belgium), where large landslides affect Cretaceous clay outcrop areas. Based on a Bayesian approach, this GIS-supported probabilistic map identifies the areas most susceptible to deep landslides. The database is comprised of the source areas of ten pre-existing landslides (i.e. a sample of 154 grid cells) and of six environmental data layers, namely lithology, proximity to active faults, slope angle and aspect, elevation and distance to the nearest valley-floor. A 30-m-resolution DEM from the Belgian National Geographical Institute is used for the analysis. Owing to the small size of the sample, a special cross-validation procedure of the susceptibility map is performed, which uses in an iterative way each of the landslides to test the predictive power of the map derived from the other landslides. Four different sets of variables are used to produce four susceptibility maps, whose prediction curves are compared. While the prediction rates associated with the models not involving the “proximity to active fault” criterion are comparable to those of the models considering this variable, strong weaknesses inherent in the fault data on which the latter rely suggest that the final susceptibility map should be based on a model that excludes any reference to fault. This highlights the difference between a triggering factor and determining factors, and in the same time broadens the scope of the produced map. A single reactivated slide is also used to test the possibility of predicting future reactivation of existing landslides in the area. Finally, the need for geomorphological control over the mathematical treatment is underlined in order to obtain realistic prediction maps.  相似文献   

Reducing model complexity for explanation and prediction   总被引：1，自引：1，他引：1  

A. Brad Murray   《Geomorphology》2007,90(3-4):178

Numerical models can be useful for explaining poorly understood phenomena or for reliable quantitative predictions. When modeling a multi-scale system, a ‘top-down’ approach—basing models on emergent variables and interactions, rather than explicitly on the much faster and smaller scale processes that give rise to them—facilitates both goals. Parameterizations representing emergent interactions range from highly simplified and abstracted to more quantitatively accurate. Empirically based large-scale parameterizations lead more reliably to accurate large-scale behavior than do parameterizations of much smaller scale processes. Conversely, purposefully simplified representations of model interactions can enhance a model's utility for explanation, clarifying the key feedbacks leading to an enigmatic behavior. For such potential insights to be relevant, the interactions in the model need to correspond to those in the ‘real’ system in some straightforward way. Such a correspondence usually holds for models constructed for predictive purposes, although this is not a requirement. The goals motivating a modeling endeavor help determine the most appropriate modeling strategies, as well as the most appropriate criteria for judging model usefulness.  相似文献   

Application and verification of fuzzy algebraic operators to landslide susceptibility mapping   总被引：4，自引：2，他引：4  

Saro Lee 《Environmental Geology》2007,52(4):615-623

The aim of this study was to apply and to verify the use of fuzzy logic to landslide susceptibility mapping in the Gangneung area, Korea, using a geographic information system (GIS). For this aim, in the study, a data-derived model (frequency ratio) and a knowledge-derived model (fuzzy operator) were combined. Landslide locations were identified by changing the detection technique of KOMPSAT-1 images and checked by field studies. For landslide susceptibility mapping, maps of the topography, lineaments, soil, forest, and land cover were extracted from the spatial data sets, and the eight factors influencing landslide occurrence were obtained from the database. Using the factors and the identified landslide, the fuzzy membership values were calculated. Then fuzzy algebraic operators were applied to the fuzzy membership values for landslide susceptibility mapping. Finally, the produced map was verified by comparing with existing landslide locations for calculating prediction accuracy. Among the fuzzy operators, in the case in which the gamma operator (λ = 0.975) showed the best accuracy (84.68%) while the case in which the fuzzy or operator was applied showed the worst accuracy (66.50%).  相似文献   

EFFECTS OF RIVER NETWORK WORKS AND SOIL CONSERVATION MEASURES ON RESERVOIR SILTATION     

Bruno MOLINO Rosa VIPARELLI Annamaria DE VINCENZO 《国际泥沙研究》2007,22(4):273-281

Knowledge of the morphological dynamics of a water course is essential for management of reservoir siltation. With an example of sedimentation in a reservoir in Basilicata, Italy, this paper demonstrates the effect on reservoir siltation of the hydraulic works, which are aimed to reduce sediment transport along the fluvial network and to prevent part of the sediment discharge from reaching the lake. The effect depends on the river type and on the the geological features of river basin slopes. The paper also shows how mass erosion can significantly contribute to development of reservoir siltation. Finally, preliminary results are provided about the time needed for river training works to be effective.  相似文献   

Geochemical modeling of magma mixing and magma reservoir volumes during early episodes of Kīlauea Volcano’s Pu‘u ‘Ō‘ō eruption     

Patrick J. Shamberger  Michael O. Garcia 《Bulletin of Volcanology》2007,69(4):345-352

Geochemical modeling of magma mixing allows for evaluation of volumes of magma storage reservoirs and magma plumbing configurations. A new analytical expression is derived for a simple two-component box-mixing model describing the proportions of mixing components in erupted lavas as a function of time. Four versions of this model are applied to a mixing trend spanning episodes 3–31 of Kilauea Volcano’s Puu Oo eruption, each testing different constraints on magma reservoir input and output fluxes. Unknown parameters (e.g., magma reservoir influx rate, initial reservoir volume) are optimized for each model using a non-linear least squares technique to fit model trends to geochemical time-series data. The modeled mixing trend closely reproduces the observed compositional trend. The two models that match measured lava effusion rates have constant magma input and output fluxes and suggest a large pre-mixing magma reservoir (46±2 and 49±1 million m³), with little or no volume change over time. This volume is much larger than a previous estimate for the shallow, dike-shaped magma reservoir under the Puu Oo vent, which grew from ∼3 to ∼10–12 million m³. These volumetric differences are interpreted as indicating that mixing occurred first in a larger, deeper reservoir before the magma was injected into the overlying smaller reservoir. Electronic Supplementary Material Supplementary material is available at and is accessible for authorized users.  相似文献   

Prediction of surface horizontal displacements, and gravity and tilt changes caused by filling the Three Gorges Reservoir   总被引：11，自引：0，他引：11  

H. Wang  H. T. Hsu  Y. Z. Zhu 《Journal of Geodesy》2002,76(2):105-114

 Horizontal displacements, and gravity and tilt changes induced by filling the Three Gorges Reservoir are modeled using elastic loading Green functions. When the water surface reaches its highest level, the effects become maximum on the reservoir banks. The longitudinal and latitudinal components of the horizontal displacements reach −8.2 and 7.7 mm respectively, gravity is increased by up to 3.4 mGal, and the prime vertical and meridian components of the tilt changes are −7.8 and −17.5 arcseconds respectively. Accordingly, the filling of the reservoir will influence values observed from global positioning system (GPS), gravimetry and tilt measurements in the area. The results given can be used to provide important corrections for extracting earthquake-related signals from observed data. Received: 19 January 2001 / Accepted: 3 September 2001  相似文献   

The international GLONASS experiment: products, progress and prospects   总被引：2，自引：0，他引：2  

R. Weber  T. A. Springer 《Journal of Geodesy》2001,75(11):559-568

 In October 1998 the IGEX field campaign, the first coordinated international effort to monitor GLONASS satellites on global basis, was started. Currently about 40 institutions worldwide support this effort either by providing GLONASS tracking data or in operating related data and analysis centers. The increasing quality and consistency of the calculated GLONASS orbits (about 25 cm early in 2000), even after the end of the official IGEX field campaign, are shown. Particular attention is drawn to the combination of precise ephemerides in order to generate a robust, reliable and complete IGEX orbits product. Some problems in modeling the effect of solar radiation pressure on GLONASS satellites are demonstrated. Finally, the expected benefits and prospects of the upcoming International GLOnass Service-Pilot Project (IGLOS-PP) of the International GPS Service (IGS) are discussed in more detail. Received: 17 August 2000 / Accepted: 12 April 2001  相似文献   

GIS支持下降雨滑坡的启动机制研究与数字仿真   总被引：13，自引：1，他引：13  

李先华  林珲  朱红旗  赵军  陈晓清  李梅  何易平  张登荣 《工程地质学报》2001,9(2):133-140

大气降雨对滑坡体的含水量和容重均有影响, 该影响具有一定的时间进程, 同时滑坡滑带土的含水率对内摩擦角和内聚力均有一定的影响。本文提出了滑坡启动的两种不同机制。通过降水滑体含水率滑体容重、滑带土内摩擦角、内聚力以及它们与滑坡稳定系数的定量关系及其时间效应, 建立起滑坡启动的速度、推力、方向和启动时间的预测、预报模型。  相似文献   

重庆市滑坡、崩塌的发育规律及区域危险性程度区划   总被引：5，自引：0，他引：5  

陆关祥  李林 《地质科学》2001,36(3):335-341

采用航空象片、遥感图像处理与野外实地考察相结合的综合研究,并根据前人的研究资料,详细解译了分布于重庆地区的各类滑坡、崩塌,总结了这些地质灾害的空间分布特征及发育规律,并对区域危险性程度进行了划分.  相似文献   

曲石湾滑坡体成因分析及防治措施研究   总被引：4，自引：1，他引：4  

吕义清  王银梅 《中国地质灾害与防治学报》2001,12(1):27-29

滑坡的形成对周围环境造成很大的影响，并严重制约地方经济发展，威胁人民生命财产安全，因此，滑坡成因及防治措施的研究具有重要意义。本文通过实际资料，分析曲石湾滑坡体的形成机理，有针对性的提出曲石湾滑坡的防治措施。  相似文献