1,720,997 research outputs found
Shallow landslides susceptibility assessment: application and comparison of physically based models in an area of Oltrepo Pavese
No full textOltrepo Pavese, which is located in the Northern Apennines of Italy, is characterized by high density of landslides and has historically suffered from widespread damage from landslides. The mass movements often developed in clayey-marly formations and are classified as complex movements. More recently extreme rainfall events have triggered shallow landslides in areas, which were not yet affected by these types of landslides. An important event happened subsequently to rapid snowmelt and intense rainfall in April 2009.
The main objective of this research is to evaluate the predictability of shallow landslide occurrence of April 2009 event using three physically based models: SHALSTAB (Montgomery and Dietrich, 1994), SINMAP (Pack et al., 1998) and TRIGRS (Baum et al., 2002). The results obtained from the three models are compared in order to highlight potential and limitation of these models for the forecasting of the potential source areas
Shallow landslides susceptibility mapping: comparison of different deterministic methods
No full text
DEM-based morphotectonics analysis of Western Ligurian Alp
No full textThe western Ligurian region shows a peculiar drainage network related to the geological events that marked this area since the Pliocenic ingression to date. From long-time, several researchers have studied the drainage evolution history of this area, with the purpose to understand how and how much its character is due to heritage ("the structure") and/or to neotectonics. Of particular relevance, a GIS type approaches permit the analysis of several scale DEM and the "enhancement" of neotectonics lineaments. This zone is in fact affected by numerous systems of faults, of which the Breil Sospel Monaco (BSM) line, and the Saorge-Taggia (ST) line, represent the principal expressions. The Saorge-Taggia system consists in a rather complex right strike slip bundle of faults, with orientation NW-SE, that is extended from the Ligurian Sea to the intersection northwards with the BSM, considered a left strike slip. Focal mechanisms which represent the earthquake of Ventimiglia of Aprils 21, 1995 (intensity 4.7), announce the presence of an inverse fault, oriented NW-SE, belongs to a system of faults, set to SE and sub-parallel to the Saorge-Taggia, identifiable probably with the Ospedaletti-Olivetta San Michele fault, even denominated in literature as Sanremo’s fault.
In this work we show some results given by the analyses of parameters extracted from digital elevation model, that give us the opportunity to develop and interpret morphometric maps. Principal morphometric indices evaluated are: slope, aspect, surface roughness, swath profiles, lineament and drainage density, isobase surface, hydraulic gradient and drainage fractal dimension. Clearly emerges from preliminary results that drainage network established its course along the main structures. Its evolution however, especially in recent era, is strongly related to the different lithological competence, differential tilting, and a differential uplift located northwards the Saorge Taggia fault and inside the Elminthoid Flysch Arc (Argentina Valley)
Comparison between different methods for shallow landslides susceptibility mapping: an example in Oltrepo Pavese (Northern Italy)
No full textThe Comparison of Hydrologic Distributed Models Computed Using Different Digital Elevation Data. An Example in the Umbria Region, Central Ital
No full textRelations between ancient settlement and the physical environment: a case study of the area from Dora Baltea river to Scrivia river (Western Po Plain - Italy)
No full textAs is known, since the prehistory, the interrelationship of the man with the landscape have become increasingly close. The study carried out on the western Po plain between the confluence of the Baltea and Scrivia Rivers, fully confirms this assumption. The study area is characterized by a typically fluvial morphology with Holocene terraces enclosed within the carved late Pleistocene plain (Main Level of Plain) and sometimes in direct contact with the Monferrato hills. The reconstruction of the evolution of the bed of the Po River has highlighted as, in certain reaches, it has been the prevalent tendency to digression and therefore instability, while in other reaches the bed was maintained more stable and less wide. Over the past two centuries, human activities especially of rice cultivation, largely cleared the remains of ancient morphologies and settlements. However it is possible to recognize a link between the distribution of population and landscape. In fact, the settlements, including the Bronze Age of Pobietto, lie mainly on higher terraces. In Roman and Medieval age, the Po river becomes very important related to its wideness or stability: the major road axis crossing the Po were located where the river is more narrow and more stable. For example in these areas, are located the cities of Valenza and Casale Monferrato, which correspond to the Roman Vardacate and Valentia. A similar location have many medieval “villenove” and the Breme and Aqualonga early medieval abbeys, which are, with Lucedio and San Genuario, the center of the re-colonization after the late-antiquity crisis. Therefore, it should be noted how are important the integrated contributions of the geomorphological and historical and archaeological study for understanding the evolution of an area
Methods for shallow landslides susceptibility mapping: an example in Oltrepo Pavese (Northern Italy)
No full textthe principal aim of this study is to compare different landslide susceptibility zonation models for predicting areas prone to shallow landsliding using both physically distributed landslide models and artificial neural networks. Necessary geotechnical and hydrological parameters were obtained coupling sample laboratory analysis and in situ measures; soil thickness was estimated using an empirical model while distribution of rainfall intensity was analyzed by performing a spatial interpolation. The predictive capabilities of these models were finally evaluated using a threshold-independent quantitative method (the ROC plot)
- …
