1,721,134 research outputs found
16th Joint Geomorphological Meeting - Morphoevolution of tectonically active belts
No full textIl volume contiene i contributi scientifici al 16th Joint Geomorphological Meeting, svoltosi a Roma, 1-5 luglio 201
Azimuthal transects of stream orientations: An advanced in understanding the regional morphotectonic setting of eastern Abruzzo (Central Italy)
Full text linkThe recently proposed azimuthal transects method was applied to the drainage network of the eastern Abruzzo area, in order to confirm the location and identify the kinematics of regional fault zones, supposed to characterise the boundaries between different morphotectonic sectors previously recognised in the area. This methodology consists of applying the azimuthal analysis of low order (younger) stream orientations along transects crossing inferred faults. Its usefulness in morphotectonic investigations is linked to the possibility of identify statistical progressive rotations of channels induced by strike-slip displacements, especially where the classical structural analysis is unlikely to be performed because of lacking pervasive deformations within outcropping rocks. At the boundaries between the three different morphotectonic sectors formerly mentioned, strike-slip offsets were identified along E-W oriented fault zones, whose presence is also suggested by some macroscopic geomorphological evidence, such as the deflection of several main rivers towards the E-W direction. These results are consistent with those get by structural and geophysical studies, thus allowing to infer that these shallow crust plio-quaternary deformations could be the effect of the activity of the E-W lithospheric deformation zone which, according to many Authors, would divide the Adriatic plate into two different portions
L'ANALISI GEOMORFICA QUANTITATIVA NELLO STUDIO DELL'EVOLUZIONE MORFOTETTONICA RECENTE DELLA FASCIA PERI-ADRIATICA MARCHIGIANO-ABRUZZESE
No full textValerio Agnesi, Claudio Caputo, Sergio Gines
Geomorphological response of fluvial and coastal terraces to Quaternary tectonics and climate in the northern Marche coastal area (central Italy) from geostatistical topographic analysis
No full text[No abstract available
The use of the Stream Length-Gradient index in morphotectonic analysis of small catchments: A case study from Central Italy
Full text linkThe aim of this work is to test an integrated quantitative geomorphic approach based on Stream Length-Gradient Index (SL Index) analysis within the small catchment of the Tarugo River in the Northern Marchean Apennines (Central Italy). The Tarugo River basin, 92 km2 wide, strikes SW-NE across the Marchean Ridge and the western sector of Marchean Piedmont. The area is characterized by a series of NW-SE trending, NE verging thrust folds affecting the Meso-Cenozoic bedrock that pass upward from dominantly carbonate to dominantly terrigenous rocks. The area investigated has been affected since the Pliocene by extensional tectonics, accompanying a regional uplift decreasing in rate north-eastwards. In this work the SL Index analysis has been integrated with the spatial analysis of the Amplitude of relief (Ar) and compared to geological and geomorphological field data. Results of this work indicate that the SL Index is a valid tool to detect the long wavelength structural effect on topography as well as the incipient local response to regional processes (i.e. regional uplift) that is often undetectable by other morphotectonic parameters. In contrast, the SL Index analysis seems not be a valid tool for discriminating the local lithological influence from the tectonic one. © 2008 Elsevier B.V. All rights reserved
Evaluation of tectonics and landscape evolution contribute as predisposing factor for a Mass Rock Creep deforming slope in the Zagros Belt (Iran)
No full textIn the hillslope landscapes of tectonically active regions, the steep topography represents the most evident result of rock uplift, valley incision and landslide erosion. In response to rock uplift, relief and hillslope dip increase linearly in time mainly due to fluvial erosion processes in landscapes affected by low to moderate tectonic forcing. Nonetheless, such a linear increase in relief and hillslope dip is limited by the reaching of threshold slope conditions associated with the hillslope material strength, until the latter is exceeded by gravitational stress giving rise to bedrock landslides. In this regard, Mass Rock Creep (MRC) process may become a primary factor for damaging rock masses so leading to slope failures that generate huge rock avalanches. MRC acts on large time-space scale through a continuous and non-linear variation of stress-strain conditions of entire portions of slopes and the coupled role of tectonics and landscape evolution represents a predisposing factor for Deep Seated Gravitational Slope Deformations (DSGSD). This research focused on the Loumar DSGSD that affects the NE slope of the Palganeh anticline in the Lorestan region (Zagros Mts., Iran), almost 90 km northwest of the Seymareh landslide which is more famous as it represents the largest landslide on Earth surface. The Loumar DSGSD evolution is strictly related to the vertical and lateral growth of the fold and to the evolution of the Seymareh river drainage system that kinematically released the slope at the bottom likely causing the initiation of the deformational process. We combined an inverse modelling of the river profiles linked to the fold uplift history and the analysis of a plano-altimetric distribution of geomorphic markers, correlated to the detectable knickpoints along the river longitudinal profiles, which allowed to constrain the main morpho-evolutionary stages of the valley. These data will be used to constrain a Landscape Evolution Model (LEM) and a stress-strain numerical model, to be performed under time-dependent creep conditions, that will be calibrated by a back analysing the slope evolution from the LEM. The final goal will be to discuss the possible role of impulsive triggers (earthquakes) in anticipating the time-to-failure of the MRC deformational process
Prediction of soil erosion and mass wasting processes in southern Tuscany using gradient boosting
No full textTime-dependent evolution of rock slopes by a multi-modelling approach
No full textThis paper presents a multi-modelling approach that incorporates contributions from morpho-evolutionary
modelling, detailed engineering-geological modelling and time-dependent stress-strain numerical modelling
to analyse the rheological evolution of a river valley slope over approximately 102 kyr. The slope is located in a
transient, tectonically active landscape in southwestern Tyrrhenian Calabria (Italy),where gravitational processes
drive failures in rock slopes. Constraints on the valley profile development were provided by a morphoevolutionary
model based on the correlation of marine and river strath terraces. Rock mass classes were identified
through geomechanical parameters that were derived fromengineering-geological surveys and outputs of a
multi-sensor slope monitoring system. The rock mass classes were associated to lithotechnical units to obtain a
high-resolution engineering-geological model along a cross section of the valley. Time-dependent stress-strain
numericalmodelling reproduced the mainmorpho-evolutionary stages of the valley slopes. The findings demonstrate
that a complex combination of eustatism, uplift and Mass Rock Creep (MRC) deformations can lead to firsttime
failures of rock slopes when unstable conditions are encountered up to the generation of stress-controlled
shear zones. The multi-modelling approach enabled us to determine that such complex combinations may have
been sufficient for the first-time failure of the S. Giovanni slope at approximately 140 ka (MIS 7), even without
invoking any trigger. Conversely, further reactivations of the landslide must be related to triggers such as earthquakes,
rainfall and anthropogenic activities. This failure involved a portion of the slope where a plasticity zone
resulted from mass rock creep that evolved with a maximumstrain rate of 40% per thousand years, after the formation
of a river strath terrace. This study demonstrates that the multi-modelling approach presented herein is a
useful tool for estimating the progressive development of slope failures because it can highlight time-dependent
continuous deformations as the major processes that drive rocky slopes to failure. This type of approach can be
devoted to the best selection of risk mitigation strategies with respect to both human life and anthropic
infrastructure
Analisi geospaziale e correlazione di superfici erosive e alluvionali relitte: ricostruzione dell’antico bacino idrografico del Fiume Farfa nel sistema idrografico del versante tirrenico (Italia centrale)
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