Search results for "Geomorfologia"

Geomorphology of the urban area of Palermo (Italy)

2020

The results of a geomorphological study carried out in the urban area of Palermo are summarized in a thematic map. Field survey, analysis of aerial photographs and topographic maps, consultation of historical documents and maps, stratigraphic and topographic reconstruction from numerous wells and subsoil data, and bibliographic search were performed, in order to display the geomorphological changes produced by man over time in a densely populated area and to define the Anthropocene of the study area. Palermo town rises along large marine terrace surfaces cut by small river valleys and bordered by wide degraded and abandoned coastal cliffs. Over the last 2700 years, this area was affected by…

Tides in the Last Interglacial: insights from notch geometry and palaeo tidal models in Bonaire, Netherland Antilles

2017

Abstract The study of past sea levels relies largely on the interpretation of sea-level indicators. Palaeo tidal notches are considered as one of the most precise sea-level indicators as their formation is closely tied to the local tidal range. We present geometric measurements of modern and palaeo (Marine Isotope Stage (MIS) 5e) tidal notches on Bonaire (southern Caribbean Sea) and results from two tidal simulations, using the present-day bathymetry and a palaeo-bathymetry. We use these two tools to investigate changes in the tidal range since MIS 5e. Our models show that the tidal range changes most significantly in shallow areas, whereas both, notch geometry and models results, suggest t…

Landslide susceptibility zonation by exploiting GIS tools and two statistical methods: binary logistic regression and multivariate adaptive regressio…

2013

In the recent years advanced statistical methods and GIS tools have been frequently used to assess landslide susceptibility. The latter is estimated by establishing statistical relationships between landscape characteristics and spatial distribution of past slope-failures. These are mapped mainly by recognizing changes on slope morphology produced by gravity. Despite of this, most of the researches on landslide susceptibility do not consider that slope-failures modify topography and associate high probability of landsliding with topographic characteristics that differ from those that led slope-failures. In this research we analyzed landslide susceptibility in the basin of the Malvello river…

Assessment of Gully Erosion Susceptibility Using Multivariate Adaptive Regression Splines and Accounting for Terrain Connectivity

2017

In this work, we assessed gully erosion susceptibility in two adjacent cultivated catchments of Sicily (Italy) by employing multivariate adaptive regression splines and a set of geo-environmental variables. To explore the influence of hydrological connectivity on gully occurrence, we measured the changes of performance occurred when adding one by one nine predictors reflecting terrain connectivity to a base model that included contributing area and slope gradient. Receiver operating characteristic (ROC) curves and the area under the ROC curve were used to evaluate model performance. Gully predictive models were trained in both the catchments and submitted to internal (in the calibration cat…

Predicting Earthquake-Induced Landslides by Using a Stochastic Modeling Approach: A Case Study of the 2001 El Salvador Coseismic Landslides

2023

In January and February 2001, El Salvador was hit by two strong earthquakes that triggered thousands of landslides, causing 1259 fatalities and extensive damage. The analysis of aerial and SPOT-4 satellite images allowed us to map 6491 coseismic landslides, mainly debris slides and flows that occurred in volcanic epiclastites and pyroclastites. Four different multivariate adaptive regression splines (MARS) models were produced using different predictors and landslide inventories which contain slope failures triggered by an extreme rainfall event in 2009 and those induced by the earthquakes of 2001. In a predictive analysis, three validation scenarios were employed: the first and the second …

Factor selection procedures in a Google Earthtm aided landslide susceptibility model: application to the Beiro river basin (Spain)

2011

A procedure to select the controlling factors connected to the slope instability has been defined. It allowed to assess the landslide susceptibility in the Rio Beiro basin (about 10 km2) over the north-eastern area of the city of Granada (Spain). Field and remote (Google EarthTM) recognition techniques allowed to generate a landslide inventory consisting in 127 phenomena. Univariate tests, using both association coefficients and validation results of single parameter susceptibility models, allowed to select among 15 controlling factors the ones that resulted as good predictor variables; these have been combined for unique conditions analysis and susceptibility maps were finally prepared. In…

Guano-related phosphate-rich minerals in European caves

2019

International audience; Guano is a typical deposit found in caves derived from the excretions of bats and in minor cases of birds. These organic deposits decompose and form a series of acid fluids and gases that can interact with the minerals, sediments, and rocks present in the cave. Over sixty phosphates are known and described from caves, but guano decay also often leads to the formation of nitrates and sulfates. In this study twenty-two European caves were investigated for their guano-related secondary minerals. Using various analytical techniques, seventeen phosphates, along with one sulfate (gypsum), were recognized as secondary products of guano decay. Among those minerals, some are …

Detection of Quaternary tectonic deformations through quantitative morphotectonic analysis in a drainage basin of northern Sicily (Italy)

2012

The use of very high resolution images for studying Posidonia oceanica reefs

2020

Posidonia oceanica is an endemic Mediterranean seagrass that forms wide and dense meadows from the surface up to about 40 m depth. This species can develop a biogenic structure called matte, a typical terraced formation built up by itself, consisting of intertwined rhizomes, roots and sediment, which may allow shoots to reach the sea surface forming reefs (récif barrière), considered natural monuments. Posidonia oceanica reefs are particularly exposed to the ongoing increase in temperature and in storm frequency and intensity due to climate change, with negative repercussions on their conservation. Much more attention must be paid to the implementation of monitoring tools able to detect ear…

First Evidence of Contourite Drifts in the North-Western Sicilian Active Continental Margin (Southern Tyrrhenian Sea)

2021

We present the results of an integrated geomorphological and seismo-stratigraphic study based on high resolution marine data acquired in the north-western Sicilian continental margin. We document for the first time five contourite drifts (marked as EM1a, EM2b, EM2, EM3a, and EM3b), located in the continental slope at depths between ca. 400 and 1500 m. EM1a,b have been interpreted as elongated mounded drifts. EM1a,b are ca. 3 km long, 1.3 km wide, and have a maximum thickness of 36 m in their center that thins northwards, while EM1b is smaller with a thickness up to 24 m. They are internally characterized by mounded seismic packages dominated by continuous and parallel reflectors. EM2 is loc…