1,721,108 research outputs found
A new Geodiversity Index as a quantitative indicator of abiotic parameters to improve landscape conservation: an Italian case study.
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GIS-based landslide hazard evaluation: The importance of input factors
No full textGIS-based landslide hazard analysis focuses on the relationships between landslide phenomena and predisposing factors such as the morphometric features of a given slope (i.e. slope, aspect, curvature). In this abstract we present and discuss the results of an analysis performed in a volcanic area SE of Rome (inner slopes of the Albano lake) based on two different morphometric data sets. The first one is derived by a DEM (10×10 m grid) extracted from the official cartography (CTR, scale 1:10.000); the other one is instead derived by a detailed DEM (1×1 m grid) resulting from a LIDAR survey performed on the study area. The first finding is that the availability of a more detailed DEM allow to better define the outlines of landslide areas, thus modifying the main input layer of the hazard analysis. In addition, the analysis showed significant differences in the landslide predisposition of morphometric parameters derived by the two DEMs
Rainfall as triggering factor of slope movements in Southern Italy: Montalbano Ionico case record
No full textThe aim of this paper is to define the role of rainfall on landslides in Southern Italy by using hydrological/statistical approach. Among the villages affected by slope movements, Montalbano Ionico has been selected as example of shallow landslides. Its most recent landslide evolution is characterized by low intensity phenomena that can be classified as retrogressive and widening composite rapid earth slide - earth fall. Their high frequency and the caused damage imply a high risk degree. This study confirms how complex and how very diverse are the phenomena that govern the effects of rainfall upon slope stability. Nevertheless, geomorphological analyses focus on the importance of some previous instability marks to predict the future slope evolution by landslides; when these marks exist, the weight of unusually heavy cumulative rainfall on the successive landslide collapse is resulted 30% - 40%
Area-scale landslide hazard and risk assessment
No full textThe paper deals with a methodology for quantitative landslide hazard and risk assessments over wide-scale areas. The approach was designed to fulfil the following requirements: (1) rapid investigation of large study areas; (2) use of elementary information, in order to satisfy the first requirement and to ensure validation, repetition and real time updating of the assessments every time new data are available; (3) computation of the landslide frequency of occurrence, in order to compare objectively different hazard conditions and to minimize references to qualitative hazard attributes such as activity states. The idea of multi-temporal analysis set forth by Cardinali et al. (Nat Hazards Earth Syst Sci 2:57–72, 2002), has been stressed here to compute average recurrence time for individual landslides and to forecast their behaviour within reference time periods. The method is based on the observation of the landslide activity through aerial-photo surveys carried out in several time steps. The output is given by a landslide hazard map showing the mean return period of landslides reactivation. Assessing the hazard in a quantitative way allows for estimating quantitatively the risk as well; thus, the probability of the exposed elements (such as people and real estates) to suffer damages due to the occurrence of landslides can be calculated. The methodology here presented is illustrated with reference to a sample area in Central Italy (Umbria region), for which both the landslide hazard and risk for the human life are analysed and computed. Results show the powerful quantitative approach for assessing the exposure of human activities to the landslide threat for a best choice of the countermeasures needed to mitigate the risk
Phase and amplitude analyses of SAR data for landslide detection and monitoring in non-urban areas located in the North-Eastern Italian pre-Alps
No full textMonitoring and modeling of sinkholes affecting the Jordanian coast of the Dead Sea through satellite interferometric techniques
No full textAn evaluation of anthropic pressure increase in a subsidence area near Rome (Italy)
No full textA study concerning the relationships between increment of anthropic pressure and subsidence phenomena is presented. The study is based on the multi-temporal analyses of air photos in the time span 1954-2005. During this period the increase of anthropic pressure has been estimated by the increment of urbanized areas and mining activity. The weight of the two antrhopic factor on the subsidence was similar. As a consequence the cause of the subsidence acceleration recorded in the last fifty years is not unique, and can be regarded to all the human activity: building, mining, pumping. In order to calculate the volume of mining activity two kinds of DEM were realized and compared: one (rough model) based on Ground Control Point extracted from the official cartography of Lazio Region (scale 1:10,000), the other (accurate model) based on GCP measured by a GPS' survey. Results showed some differences but rough model resulted enough accurate for the purpose of this study
Landslide phenomena in the area of Pomarico (Basilicata-Italy): methods for modelling and monitoring
No full textThis paper takes into consideration landslide phenomena in the clayey slopes facing the built-up area of Pomarico which is situated in the southern part of the "Fossa Bradanica", in Basilicata (Italy). Based on the great number of geologic, geomorphologic and historic informations a geotechnical model of the slope was built. Particular attention has been paid to define the geotechnical parameters of the soil and which mechanical models are to be used. The studies point out a correlation between the water level in the detritus cover and the stability condition of the slope showing that phenomena at first located at the foot of the slope spread quickly towards its summit as the piezometric height increase
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