共查询到20条相似文献，搜索用时 437 毫秒
1.
Elena Fernández Ana Colubi Gil González-Rodríguez Soledad Anadón 《Natural Hazards》2012,62(2):459-483
The importance of the historical information in flood analysis has previously been underlined. In this context, we present an integral methodology aimed at the establishment of return periods of different flood units on the unique basis of historical data. Specifically, the reconstruction of the flood chronology extended back to 1900, complemented with a new (historical data-based) event intensity index, and the return period estimation will be addressed. Since some of the historical data are collected from interviews and other sources with different degrees of precision and reliability, two kinds of uncertainty will be considered; namely the statistical variability and the imprecision. We propose an innovative methodology involving intervals (ranges), fuzzy sets, and weights to formalize and average the criteria that determine the importance of the different events. On the other hand, to take into account the statistical variability, we propose to estimate the return period in a flexible and efficient way by considering bootstrap confidence intervals. The methodology is particularly useful at ungauged, or partially gauged, flood inundation areas, where the existing flow gauge stations do not give the flood series at the point of interest. A case study developed in Spain is discussed. The results are supported by two recent events, which have been mapped at 1:5000 scale. 相似文献
2.
基于二元统计的区域地质灾害敏感性评价--以四川雅安雨城区为例 总被引：5，自引：0，他引：5
借鉴区域地质灾害敏感性评价的各种方法，给出了基于二元统计的地质灾害敏感性评价方法，并在雅安市雨城区地质灾害敏感忡评价中进行了试验。本方法主要有以下优点：操作简单、数据容易准备、效率高、评价合理准确、适用于各种精度（比例尺），有着较好的推广应用价值。 相似文献
3.
Dalia Bach Kirschbaum Robert Adler Yang Hong Sujay Kumar Christa Peters-Lidard Arthur Lerner-Lam 《Environmental Earth Sciences》2012,66(6):1683-1696
The increasing availability of remotely sensed data offers a new opportunity to address landslide hazard assessment at larger
spatial scales. A prototype global satellite-based landslide hazard algorithm has been developed to identify areas that may
experience landslide activity. This system combines a calculation of static landslide susceptibility with satellite-derived
rainfall estimates and uses a threshold approach to generate a set of ‘nowcasts’ that classify potentially hazardous areas.
A recent evaluation of this algorithm framework found that while this tool represents an important first step in larger-scale
near real-time landslide hazard assessment efforts, it requires several modifications before it can be fully realized as an
operational tool. This study draws upon a prior work’s recommendations to develop a new approach for considering landslide
susceptibility and hazard at the regional scale. This case study calculates a regional susceptibility map using remotely sensed
and in situ information and a database of landslides triggered by Hurricane Mitch in 1998 over four countries in Central America.
The susceptibility map is evaluated with a regional rainfall intensity–duration triggering threshold and results are compared
with the global algorithm framework for the same event. Evaluation of this regional system suggests that this empirically
based approach provides one plausible way to approach some of the data and resolution issues identified in the global assessment.
The presented methodology is straightforward to implement, improves upon the global approach, and allows for results to be
transferable between regions. The results also highlight several remaining challenges, including the empirical nature of the
algorithm framework and adequate information for algorithm validation. Conclusions suggest that integrating additional triggering
factors such as soil moisture may help to improve algorithm performance accuracy. The regional algorithm scenario represents
an important step forward in advancing regional and global-scale landslide hazard assessment. 相似文献
4.
A Methodology for Establishing a Data Reliability Measure for Value of Spatial Information Problems 总被引：2，自引：0，他引：2
We propose a value of information (VOI) methodology for spatial Earth problems. VOI is a tool to determine whether purchasing
a new information source would improve a decision-makers’ chances of taking the optimal action. A prior uncertainty assessment
of key geologic parameters and a reliability of the data to resolve them are necessary to make a VOI assessment. Both of these
elements are challenging to obtain, as this assessment is made before the information is acquired. We present a flexible prior
geologic uncertainty modeling scheme that allows for the inclusion of many types of spatial parameter. Next, we describe how
to obtain a physics-based reliability measure by simulating the geophysical measurement on the generated prior models and
interpreting the simulated data. Repeating this simulation and interpretation for all datasets, a frequency table can be obtained
that describes how many times a correct or false interpretation was made by comparing them to their respective original model.
This frequency table is the reliability measure and allows a more realistic VOI calculation. An example VOI calculation is
demonstrated for a spatial decision related to aquifer recharge where two geophysical techniques are considered for their
ability to resolve channel orientations. As necessitated by spatial problems, this methodology preserves the structure, influence
and dependence of spatial variables through the prior geological modeling and the explicit geophysical simulation and interpretations. 相似文献
5.
综合统计模型和物理模型的地质灾害精细评估——以福建省龙山社区为例 总被引：1，自引：0，他引：1
地质灾害易发性和危险性评价对象相同但评价内容有差异,即两者表达地质灾害的时间、空间和强度信息各有不同。本文将崩塌滑坡易发性中的统计模型和危险性评价中的物理模型进行结合,综合统计模型客观预测空间位置信息的优点以及物理模型模拟包含地质灾害发生机制的优势,弥补了区域统计模型无法预测灾害强度信息的不足,也对物理模型模拟的空间位置进行了有效的控制和修正,进而完成区域崩塌滑坡的易发性和危险性等级综合分析,实现对区域崩塌滑坡潜在高风险位置的精细评估。本文以福建省福鼎市龙山社区为例,利用野外获取的高清影像、地形、钻孔和地质灾害等数据,通过综合统计模型评价和物理模型危险性评估,完成潜在高风险位置的精细化分析。研究结果表明:需要进行重点排查治理的区域约占社区附近山体总面积的26.92%;研究区域内需要进行集中排查与治理的区域有5个,其中3个区域需要进行重点治理,其潜在高风险区域与野外地质灾害调查区域隐患点吻合;5个高风险区域直接对180幢左右楼房（约360余户居民）的安全构成威胁,该评估将野外调研中划定的大范围高风险区域精细化处理,并验证了该评价方法体系的可行性。该评价方法体系为区域崩塌滑坡地质灾害精细化排查和治理提供了工作思路和指导。 相似文献
6.
7.
Regional landslide susceptibility zoning with considering the aggregation of landslide points and the weights of factors 总被引：4，自引：0，他引：4
In this paper, we propose a methodology for landslide susceptibility assessment at a regional scale in Yunnan, southwestern province of China. A landslide inventory map including 3,242 landslide points was prepared for the study area. Five factors recognized as correlated to landslide (namely, lithology, relative relief, tectonic fault density, rainfall, and road density) were analyzed and mapped in geographic information system. An index expressing the correlation between each factor and landslides [called class landslide susceptibility index (CLSI)] was proposed in the study. While analyzing landslide distribution in a large area, point aggregation might be expected. To quantify the uncertainty caused by aggregation, class landslide aggregation index was proposed. To account for the importance of each of the factors in the landslide susceptibility assessment, some weights were calculated by means of analytic hierarchy process. We propose a weighted class landslide susceptibility model (WCLSM), obtained by the combination of CLSI values of each factor with the correspondent weight. WCLSM performance in the study area was evaluated comparing the results obtained by first modeling all landslides and then by performing a time partition. The model was run including only landslides that occurred before 2009 and then validated with respect to landslides that occurred after 2009. The prediction–rate curve shows that the WCLSM model provides a good prediction for the study area. Of the study area, 21.4 % shows very high and high susceptibility and includes the 87.7 % of the number of landslides that occurred after 2009. 相似文献
8.
Landslide susceptibility mapping is most effective if detailed surface and subsurface information can be combined with authoritative landslide catalogs or a deep understanding of local conditions. However, these types of homogeneous input data and catalogs are frequently not available over large areas. In this study, we model landslide susceptibility in Central America and the Caribbean islands by combining three globally available datasets and one regional dataset with fuzzy overlay. This primarily heuristic model provides the flexibility to test a range of different contributing variables and the capability to compare landslide inventories within the model framework that vary greatly in their size, spatiotemporal scope, and collection methods. We create a regional susceptibility map and evaluate its performance using receiver operating characteristics for both continuous and binned susceptibility values. This susceptibility map forms the basis for a near-real-time landslide hazard assessment system that couples susceptibility with rainfall and soil moisture triggers to estimate potential landslide activity at a regional scale. The application of this susceptibility model at the regional scale provides a foundation for transferring the methodology to other geographic areas. 相似文献
9.
Evaluation of soil collapse potential in regional scale 总被引：2，自引：1，他引：1
Mehdi Momeni Ali Shafiee Mojtaba Heidari Mohammad Kazem Jafari Mohammad Reza Mahdavifar 《Natural Hazards》2012,64(1):459-479
Collapsible soils have considerable strength and stiffness in their dry natural state but settle dramatically when they become wet. This paper documents a low-cost, qualitative evaluation scheme using fuzzy set analysis to determine site collapsibility based on subjective knowledge of the geological, geotechnical, and environmental conditions and their uncertainty. For each category, factors or subcategories were defined in a decision tree based on relevant literature. Each category and subcategory was then weighted or rated using linguistic terms developed from expert assessment. The linguistic data or information obtained from the assessments was represented and processed using fuzzy sets. To calibrate the criteria, 87 collapse potential tests were performed on undisturbed soil samples gathered from 27 different locations throughout Iran, leading to the definition of a standard collapse potential fuzzy set. Finally, on the basis of the established criteria, a collapse potential map was prepared for a suburban area in the western part of the city of Kerman, Iran. 相似文献
10.
Analysis and Estimation of Natural Processes with Nonhomogeneous Spatial Variation Using Secondary Information 总被引：1，自引：0，他引：1
Natural processes encountered in mining, hydrogeologic, environmental, etc. applications usually are poorly known because of scarcity of data over the area of interest. Therefore, stochastic estimation techniques are the tool of choice for a careful accounting of the heterogeneity and uncertainty involved. Within such a framework, a better utilization of all available data concerning the process of interest and all other natural processes related to it, is of primary importance. Because many natural processes show complicated spatial trends, the hypothesis of spatial homogeneity cannot be invoked always, and the more general theory of intrinsic spatial random fields should be employed. Efficient use of secondary information in terms of the intrinsic model requires that suitable permissibility criteria for the generalized covariances and cross-covariances are satisfied. A set of permissibility criteria are presented for the situation of two intrinsic random fields. These criteria are more general and comprehensive than the ones currently available in the geostatistical literature. A constrained least-square technique is implemented for the inference of the generalized covariance and cross-covariance parameters, and a synthetic example is used to illustrate the methodology. The numerical results show that the use of secondary information can lead to significant reductions in the estimation errors. 相似文献
11.
In areas with long periods of drought, it is essential to implement strategies to manage the available water resource. Tierra Nueva Basin is affected by this situation, consequently the farm production and livestock holdings are affected and the people don’t have access to enough water. In this paper, we propose an integrative methodology based on mathematical tools such as hypsometric and morphometric analysis applying geographic information systems. The proposal is strengthened with the aggregation of geological-structural, morphometrical, hypsometrical parameters and climatological information through a precipitation analysis provided by the National Water Commission from 1962 to 2010. According to the available data and the results obtained through the implemented proposal, an acceptable level of reliability is inferred allowing to determine areas structurally suitable for the use of surface water and its uptake. The methodology that we propose facilitates and simplifies the processes of searching and exploring locations suitable for surface water capture in arid and semi-arid zones, identifying in a qualitative and quantitative manner the optimal zone. For the case study, test-and-validation of the methodology the Tierra Nueva Basin in San Luis Potosí, México was selected. Tierra Nueva is a semi-arid site where “La Muñeca” dam is located. The results obtained in this work confirm the location of the “La Muñeca” dam as one of the most suitable areas for water collection. The methodology that we propose is a useful tool for the studies of water capturing purposes in arid and semi-arid zones. 相似文献
12.
The threshold between geochemical background and anomalies can be influenced by the methodology selected for its estimation. Environmental evaluations, particularly those conducted in mineralized areas, must consider this when trying to determinate the natural geochemical status of a study area, quantifying human impacts, or establishing soil restoration values for contaminated sites. Some methods in environmental geochemistry incorporate the premise that anomalies (natural or anthropogenic) and background data are characterized by their own probabilistic distributions. One of these methods uses exploratory data analysis (EDA) on regional geochemical data sets coupled with a geographic information system (GIS) to spatially understand the processes that influence the geochemical landscape in a technique that can be called a spatial data analysis (SDA). This EDA–SDA methodology was used to establish the regional background range from the area of Catorce–Matehuala in north-central Mexico. Probability plots of the data, particularly for those areas affected by human activities, show that the regional geochemical background population is composed of smaller subpopulations associated with factors such as soil type and parent material. This paper demonstrates that the EDA–SDA method offers more certainty in defining thresholds between geochemical background and anomaly than a numeric technique, making it a useful tool for regional geochemical landscape analysis and environmental geochemistry studies. 相似文献
13.
The influence of systematically incomplete shallow landslide inventories on statistical susceptibility models and suggestions for improvements 总被引：1，自引：1，他引：0
Complete landslide inventories are rarely available. The objectives of this study were to (i) elaborate the influence of incomplete landslide inventories on statistical landslide susceptibility models and to (ii) propose suitable modelling strategies that can reduce the effects of inventory-based incompleteness. In this context, we examined whether the application of a novel statistical approach, namely mixed-effects models, enables predictions that are less influenced by such inventory-based errors.The study was conducted for (i) an area located in eastern Austria and (ii) a synthetically generated data set. The applied methodology consisted of a simulation of two different inventory-based biases and an in-depth evaluation of subsequent modelling results. Inventory-based errors were simulated by gradually removing landslide data within forests and selected municipalities. The resulting differently biased inventories were introduced into logistic regression models while we considered the effects of including or excluding predictors that are directly related to the respective inventory-based bias. Mixed-effects logistic regression was used to account for variation that was due to an inventory-based incompleteness.The results show that most erroneous predictions, but highest predictive performances, were obtained from models generated with highly incomplete inventories and predictors that were able to directly describe the respective incompleteness. An exclusion of such bias-describing predictors led to systematically confounded relationships. The application of mixed-effects models proved valuable to produce predictions that were least affected by inventory-based errors.This paper highlights that the degree of inventory-based incompleteness is only one of several aspects that determine how an inventory-based bias may propagate into the final results. We propose a four-step procedure to deal with incomplete inventories in the context of statistical landslide susceptibility modelling. 相似文献
14.
Application of Dempster-Shafer theory of evidence to GIS-based landslide susceptibility analysis 总被引：9，自引：2，他引：7
No-Wook Park 《Environmental Earth Sciences》2011,62(2):367-376
GIS-based spatial data integration tasks for predictive geological applications, such as landslide susceptibility analysis,
have been regarded as one of the primary geological application issues of GIS. An efficient framework for proper representation
and integration is required for this kind of application. This paper presents a data integration framework based on the Dempster-Shafer
theory of evidence for landslide susceptibility mapping with multiple geospatial data. A data-driven information representation
approach based on spatial association between known landslide occurrences and input geospatial data layers is used to assign
mass functions. After defining mass functions for multiple geospatial data layers, Dempster’s rule of combination is applied
to obtain a series of combined mass functions. Landslide susceptibility mapping using multiple geospatial data sets from Jangheung
in Korea was conducted to illustrate the application of this methodology. The results of the case study indicated that the
proposed methodology efficiently represented and integrated multiple data sets and showed better prediction capability than
that of a traditional logistic regression model. 相似文献
15.
广佛肇地区岩溶塌陷易发性分析 总被引：1，自引：1，他引：0
广州、佛山和肇庆市(广佛肇地区)作为经济发达地区,岩溶塌陷时有发生,给当地人民群众和经济发展带来较大威胁。依托区域地质调查成果,根据岩溶地质条件情况,选择岩溶塌陷分布特征、岩溶发育条件、覆盖层特征、地质构造、水文地质条件和土地利用类型6个因素,系统研究各个因素对岩溶塌陷形成的作用和各个因素之间的权重关系。在此基础上,运用地理信息系统技术和多元统计方法(层次分析法),建立岩溶塌陷发育的多因素判别模型,进而对广佛肇地区划分出高、中等和低易发区域,并根据岩溶塌陷易发区划,编制广佛肇地区重大基础设施岩溶塌陷易发区划应用图集,统计出重大基础设施所在易发区范围。 相似文献
16.
本文以北京市怀柔区为例,通过现场调查,对688处崩塌灾害分别以面数据和点数据的形式获取了两套编目图。根据现场调查和资料分析,选取岩性、地形、断裂和道路建设作为该区崩塌灾害的主控因素,采用频率比(FR)模型对崩塌灾害的易发性进行了评价。为了对评价结果的预测性进行检验,采用随机分割法,选取了415处崩塌用于频率比模型的计算,剩余的273处崩塌用于评价结果预测性的验证。预测曲线表明,基于崩塌面数据的评价结果比基于点数据的评价结果具有明显的优越性。根据基于面数据的频率比模型评价结果,可以将研究区的崩塌灾害易发性划分为5个等级:较低易发(占全区14%)、低易发(占全区20%)、中等易发(占全区27%)、高易发(占全区22%)和极高易发(占全区17%)。相关工作和结论可以为区域地质灾害易发性评价中编目图的编制提供参考,并为怀柔区区域国土利用和防灾减灾提供指导。 相似文献
17.
The use of the possibility theory to investigate the epistemic uncertainties within scenario-based earthquake risk assessments 总被引：1，自引：0，他引：1
This paper presents a methodology to represent and propagate epistemic uncertainties within a scenario-based earthquake risk
model. Unlike randomness, epistemic uncertainty stems from incomplete, vague or imprecise information. This source of uncertainties
still requires the development of adequate tools in seismic risk analysis. We propose to use the possibility theory to represent
three types of epistemic uncertainties, namely imprecision, model uncertainty and vagueness due to qualitative information.
For illustration, an earthquake risk assessment for the city of Lourdes (Southern France) using this approach is presented.
Once adequately represented, uncertainties are propagated and they result in a family of probabilistic damage curves. The
latter is synthesized, using the concept of fuzzy random variables, by means of indicators bounding the true probability to
exceed a given damage grade. The gap between the pair of probabilistic indicators reflects the imprecise character of uncertainty
related to the model, thus picturing the extent of what is ignored and can be used in risk management. 相似文献
18.
High-steep slopes in open pit mines are much more likely to collapse due to mining operations. Challenges such as data acquisition, precise numerical models and adaptable methodologies have impeded more reliable results of slope stability analysis based on the current methods. Within this context, this paper proposes a combined methodology using light detection and ranging technology to capture high-resolution slope geometry, three-dimensional geological and geotechnical modeling technologies for creating high-quality numerical simulation models and finite-element slope stability analyses combined with a new automatic strength reduction technique to analyze complex geotechnical problems. At the end, the methodology introduces a time series analysis to improve the reliability of the calculated factor of safety. A case study in the deepest open pit mine in Hambach, Germany, was conducted to test and demonstrate the effectiveness and applicability of the proposed methodology. 相似文献
19.
目前,日照市因废弃矿山引发的地质灾害主要表现在崩塌、滑坡等方面,对废弃矿山进行地质灾害预测并根据实际情况制定治理方案,不但能有效避免因地质灾害造成的损失,又能绿化生态环境,消除视觉污染。通过对日照市岚山区巨峰镇西赵村崩塌体的基本特征及现状进行影响评估,并就西赵村崩塌地质灾害的治理方案进行了初步分析探讨,为日照市因废弃矿山普遍引发崩塌地质灾害的防治提供了理论基础资料。 相似文献
20.
沉积记录研究的现代过程视角 总被引：1，自引：1，他引：0
沉积记录是揭示地球演化的主要数据来源之一,地层学提供了宏观大尺度沉积记录的分析方法,而沉积学则提高了沉积记录的时空分辨率。但上述方法主要是针对沉积体系特征和现象信息的,而有关沉积体系过程和机制信息的提取还较为薄弱。通过评述现代过程在沉积记录研究中的定位,提出了新的科学问题。研究结果表明,基于现代过程研究的勘测性模拟是一种值得追求的方法。经典数值模拟依赖于未知变量与方程个数相同的控制方程,用实测数据作为验证材料,而勘测性模拟是控制方程加工作假说构成的体系,其模型输出指示了过程—产物关系。因此,通过现代沉积体系模拟及其与钻孔资料的对比,可以获取沉积记录所含的过程和机制信息。勘测性模拟也是地球久远时代沉积记录的潜在分析工具。 相似文献