Search results for " Geologia"

Sistematica, tafonomia e paleobiogeografia delle associazioni ad ammoniti del Giurassico Medio e Superiore della Sicilia Occidentale con particolare …

2012

Antropizzazione costiera e posizione della linea di riva: la spiaggia di san leone (Agrigento)

2016

In questo lavoro viene descritto un metodo di studio applicato al monitoraggio di una spiaggia dalle particolari caratteristiche dinamiche, causate proprio dal crescente sviluppo antropico avuto negli ultimi 50 anni. Il caso studio è la spiaggia di San Leone (37°15′41″N 13°35′20″E) appartenente all’Unità Fisiografica n.10 e localizzata a sud della città di Agrigento, tra le foce del fiume Akragas a NW e la foce del fiume Naro a SE (Fig. 1). Dagli anni '70 ad oggi, la spiaggia è stata oggetto di molti cambiamenti che hanno prodotto disequilibri nelle dinamiche litoranee che si sono evidenziate nel tempo attraverso avanzamenti e/o arretramenti della linea e aree ad alta criticità da erosione.…

Geological, hydrogeological and geochemical characterization of aquifers in coastal areas (Ragusa-Donnalucata Area, Sicily, Italy)

2005

Carbonate groundwater systems hosted in coastal areas are of particular concern, for multi-fold reasons. First, in Sicily - as in many other islands – coastal areas are the most densely populated: this increase of anthropogenic pressure considerably raises the potential risks of groundwater contamination. This is even more dangerous considering the fact that groundwater is often the main source of potable water for coastal communities, especially since rivers and ponds near the shore are brackish. Secondly, coastal areas are the sites of potential interactions between the groundwater systems and seawater, the morphology and the location of this interface being a complex function, of groundw…

Landslide susceptibility mapping using precipitation data, Mazandaran Province, north of Iran

2017

Precipitation is a nonlinear and complex phenomenon and varies in time and space. It is also evident that there is a link between precipitation and shallow landslides, and precipitation is always considered as a landslide-triggering factor. This study aims to investigate the relationship between the characteristics of precipitation and the historical shallow landslides in Mazandaran Province, north of Iran. For this purpose, the spatial variability of rainfall was analyzed using monthly rainfall data collected at 15 synoptic stations distributed over the region between 1981 and 2014. Monthly precipitation and other derived parameters were used, and a hybrid model combining principal compone…

Detection of homogeneous precipitation regions at seasonal and annual time scales, northwest Iran

2017

Abstract Detection of homogeneous climate areas is a challenging issue, which can be affected by different criteria. One of the most prominent factors is choosing the time scale, which can lead to different spatial and temporal patterns. Total precipitation is a key factor in climatological studies, and studying its distribution is of utmost importance. The combination of principal components analysis and cluster analysis is used for homogeneous precipitation areas' detection. Hence, the spatial pattern of total precipitation was investigated in northwestern Iran during the past two decades (1991–2010) on seasonal and annual time scales. The results of clustering on each time scale were val…

The role of the diagnostic areas in the assessment of landslide susceptibility models: a test in the sicilian chain

2011

Abstract The aim of the research was to verify and compare the predictive power of different diagnostic areas in assessing landslide susceptibility with a multivariate approach. Scarps, landslide areas (the union between scarp and accumulation zones) and areas uphill from crowns, for rotational slides, source or scarp areas and landslide areas, for flows, have been tested. A multivariate approach was applied to assess the landslide susceptibility on the basis of three selected conditioning factors (lithology, slope angle, and topographic wetness index), which were combined in a Unique Condition Unit (UCU) layer. By intersecting the UCU layer with the vector layer of the diagnostic areas, la…

Active faulting and continental slope instability in the Gulf of Patti (Tyrrhenian side of NE Sicily, Italy): a field, marine and seismological joint…

2016

The Gulf of Patti and its onshore sector represent one of the most seismically active regions of the Italian Peninsula. Over the period 1984–2014, about 1800 earthquakes with small-to-moderate magnitude and a maximum hypocentral depth of 40 km occurred in this area. Historical catalogues reveal that the same area was affected by several strong earthquakes such as the Mw = 6.1 event in April 1978 and the Mw = 6.2 one in March 1786 which have caused severe damages in the surrounding localities. The main seismotectonic feature affecting this area is represented by a NNW–SSE trending right-lateral strike-slip fault system called ‘‘Aeolian–Tindari–Letojanni’’ (ATLFS) which has been interpreted a…

Evidence of positive tectonic inversion in the north-central sector of the Sicily Channel (Central Mediterranean)

2016

In order to unravel the tectonic evolution of the north-central sector of the Sicily Channel (Central Mediterranean), a seismo-stratigraphic analysis of single- and multi-channel seismic reflection profiles has been carried out. This allowed to identify, between 20 and 50 km offshore the central-southern coast of Sicily, a ~80-km-long deformation belt, characterized by a set of WNW–ESE to NW–SE fault segments showing a poly-phasic activity. Within this belt, we observed: i) Miocene normal faults reactivated during Zanclean–Piacenzian time by dextral strike-slip motion, as a consequence of the Africa–Europe convergence; ii) releasing and restraining bend geometries forming well-developed pul…

Slope units-based flow susceptibility model: using validation tests to select controlling factors

2011

A susceptibility map for an area, which is representative in terms of both geologic setting and slope instability phenomena of large sectors of the Sicilian Apennines, was produced using slope units and a multiparametric univariate model. The study area, extending for approximately 90 km2, was partitioned into 774 slope units, whose expected landslide occurrence was estimated by averaging seven susceptibility values, determined for the selected controlling factors: lithology, mean slope gradient, stream power index at the foot, mean topographic wetness index and profile curvature, slope unit length, and altitude range. Each of the recognized 490 landslides was represented by its centroid po…

Seismic stratigraphy of upper Quaternary shallow-water contourite drifts in the Gulf of Taranto (Ionian Sea, southern Italy)

2018

Abstract The occurrence of articulated seafloor morphology over continental shelf-upper slope environments, may result in a significant change in the patterns and intensity of basin-scale thermohaline circulation during eustatic sea-level fluctuations. These changes may cause, in turn, erosion, deposition and/or transport of sediments at the seafloor, to form shallow-water contourite drifts. Here we investigate this process in the NW sector of the Gulf of Taranto (Ionian Sea) during and following the Last Glacial Maximum (LGM), by integrating multibeam bathymetric data, ultra-high resolution seismic-reflection data and gravity core data. Sea level fall caused subaerial exposure of the summi…