Evaluation of Flood and Landslide Risk to the Population of Italy

We have compiled a database of floods and landslides that occurred in Italy between AD 1279 and 2002 and caused deaths, missing persons, injuries, and homelessness. Analysis of the database indicates that more than 50,593 people died, went missing, or were injured in 2580 flood and landslide events. Harmful events were inventoried in 26.3% of the 8103 Italian municipalities. Fatal events were most frequent in the Alpine regions of northern Italy and were caused by both floods and landslides. In southern Italy, landslides were the principal agents of fatalities and were most numerous in the Campania region. Casualties were most frequent in the autumn. Fast-moving landslides, including rock falls, rockslides, rock avalanches, and debris flows, caused the largest number of deaths. In order to assess the overall risk posed by these processes, we merged the historical catalogs and identified 2682 “hydrogeomorphological” events that triggered single or multiple landslides and floods. We estimated individual risk through the calculation of mortality rates for both floods and landslides and compared these rates to the death rates for other natural, medical, and human-induced hazards in Italy. We used the frequency distribution of events with fatalities to ascertain the magnitude and frequency of the societal risks posed by floods and landslides. We quantified these risks in a Bayesian model that describes the probabilities of fatal flood and landslide events in Italy.     

岸坡侵蚀及其防治

岸坡侵蚀是土地侵蚀的一个类型．它进一步又可划分为岸坡崩塌、滑坡侵蚀，岸坡塌陷侵蚀，岸坡沟谷侵蚀和岸坡洪水侵蚀。本文在详细分析各类岸坡侵蚀的基础上，提出了岸坡侵蚀的特点和防治对策。     

重庆市崩塌和滑坡的危险性评价

根据大量的勘查和社会经济统计资料,建立数学模型,对重庆市崩塌和滑坡的危险性指数进行了计算并划分出危险度．在此基础上,绘出区域灾害危险性分布图并对其危险性进行了评价。     

三峡库区滑坡稳定性评价研究

三峡水库蓄水后 ,库水位将在 14 5～ 175m范围内波动 ,动水压力和水的软化作用是滑坡失稳的主要因素。库区滑坡稳定性评价规范要求采用不平衡推力法 ,但在考虑库水位下降产生的渗透力时 ,对渗流浸润线的确定缺乏理论依据 ,更没有实测数据的支持。为此 ,笔者运用一维的布辛内斯克方程 ,研究三峡水库蓄水后库水位下降和暴雨作用下滑坡渗流浸润线的变化规律 ;建立了渗流作用下滑坡稳定性评价模型 ;分析降速、渗透系数、暴雨等对滑坡稳定性的影响。     

滑坡失稳破坏概率及可靠度研究

本文讨论了滑坡失稳破坏概率及可靠度分析方法，并对清江水布垭坝址大岩淌滑坡进行了计算，所得结论基本符合实际。     

Comparing Landslide Maps: A Case Study in the Upper Tiber River Basin, Central Italy

/ The preparation of landslide maps is an important step in any landslide hazard assessment. Landslides maps are prepared around the world, but little effort is made to assess their reliability, outline their main characteristics, and pinpoint their limitations. In order to redress this imbalance, the results of a long-term research project in the Upper Tiber River basin in central Italy are used to compare reconnaissance and detailed landslide inventory maps, statistical and geomorphologically based density maps, and landslide hazard maps obtained by multivariate statistical modeling. An attempt is made to discuss advantages and limitations of the available maps, outlining possible applications for decision-makers, land developers, and environmental and civil defence agencies. The Tiber experiment has confirmed that landslides can be cost-effectively mapped by interpreting aerial photographs coupled with field surveys and that errors and uncertainties associated with the inventory can be quantified. The experiment has shown that GIS makes it easy to prepare landslide density maps and facilitates the production of statistically based landslide hazard models. The former supply an overview of the distribution of landslides that is easily comprehended but do not provide insight on the causes of instability. The latter, giving insight into the causes of instability, are diagnostically powerful, but are difficult to prepare and exploit.     

Stability analysis and comprehensive treatment methods of landslides under complex mining environment—A case study of Dahu landslide from Linbao Henan in China

A case study of Dahu landslide from Linbao Henan in China was discussed in this paper. Based on various kinds of basic data, the 3D numerical model of a geological structure which possesses all kinds of information including the mechanical characteristics and the geometrical parameters of geological discontinuities were known from previous works. Thus, both the whole geological structure and all kinds of geological components involved in a slope can be visualized on computer, the complicated analysis and calculation can be then carried out easily and effectively. Firstly, the combination of 3D numerical model with the limit equilibrium analysis theory in slope stabilization can easily provide the present stability factor. Then according to monitoring data of the total station, the potential sliding trends are analyzed if landslides do not occur. Secondly, there are a number of uncertainties on the factors of multi-forms of disaster, such as, rainfall, earthquake, and mined-out area. The unascertained mathematics theory is applied to the stability comprehensive evaluation. It shows four landslide bodies get to be at unstable state if there are some inducements. Thirdly, sliding distance and movement scope were predicted if landslides occur. On the basis of the analysis above, the treatment of the landslide body called isolated method of culvert was proposed. It has solved the contradiction of landslide and mining radically, and provides important technical assurance for safety and sustainable development of mine.     

滑坡灾害经济评价初探

本文根据滑坡灾害是自然过程迭加在社会和经济基础上形成的思想，结合滑坡灾害的具体情况，提出了滑坡灾害的经济评价方法，并引入两个具体实例给予了描述。     

Application of Likelihood Ratio and Logistic Regression Models to Landslide Susceptibility Mapping Using GIS

For landslide susceptibility mapping, this study applied and verified a Bayesian probability model, a likelihood ratio and statistical model, and logistic regression to Janghung, Korea, using a Geographic Information System (GIS). Landslide locations were identified in the study area from interpretation of IRS satellite imagery and field surveys; and a spatial database was constructed from topographic maps, soil type, forest cover, geology and land cover. The factors that influence landslide occurrence, such as slope gradient, slope aspect, and curvature of topography, were calculated from the topographic database. Soil texture, material, drainage, and effective depth were extracted from the soil database, while forest type, diameter, and density were extracted from the forest database. Land cover was classified from Landsat TM satellite imagery using unsupervised classification. The likelihood ratio and logistic regression coefficient were overlaid to determine each factors rating for landslide susceptibility mapping. Then the landslide susceptibility map was verified and compared with known landslide locations. The logistic regression model had higher prediction accuracy than the likelihood ratio model. The method can be used to reduce hazards associated with landslides and to land cover planning. Note: This version was published online in June 2005 with the cover date of August 2004.     

Historical and Geological Evidence for Seismic Origin of Newly Recognized Landslides in Southeastern Sicily, and Its Significance inTerms of Hazard

Old, large, and dormant landslides were unexpectedly found in southeastern Sicily, a territory of known seismicity but commonly considered as landslide-free or almost so. Purposely undertaken investigations revealed that: (1) these landslides are scarcely compatible with the local geoclimatic environment; (2) they usually show low-angle basal shear surfaces, despite the fact that the properties of the forming material are generally good; (3) they fulfill the known relationships between earthquake magnitude and epicenter–landslide distance; (4) sources coeval with high-energy historical earthquakes occurred in 1169, 1542 and 1693 testify to the occurrence of earthquake-triggered landsliding; and (5) documentary material (presented here for the first time) correlates with certainty a specific landslide to the 1693 earthquake. This geological and historical evidence, accompanied by the absence of contrasting elements, leads us to conclude that these landslides are earthquake-triggered. Because of their typological and geometrical characteristics, nearly all landslides can be reactivated, which has serious implications in terms of hazard, particularly with respect to lines of communication. Obviously, every action aimed at preventing or mitigating risks must start from the awareness of the causative processes, a condition substantially unsatisfied at the moment in SE Sicily. The paper concludes by emphasizing the opportunity not to trust excessively beliefs that, although shared, have never been really checked.