Search results for " geofisica"

Seismo-stratigraphic model of “La Bandita” area in the Palermo Plain (Sicily, Italy) through HVSR inversion constrained by stratigraphic data

2018

Ambient noise Horizontal-to-Vertical Spectral Ratio (HVSR) technique is commonly used approach to obtain 1D models of the shear-wave velocity in the shallow surface of an investigated area. However, obtained models can have a wide margin of uncertainty if inversions have not been appropriately constrained by detailed stratigraphic information. An application of HVSR inversion constrained by lithostratigraphic data is presented in order to verify the effectiveness of this technique for purposes of geological and geophysical reconstruction of a sedimentary basin in a densely urbanized area. This is often the case of seismic microzonation studies, in which almost all the information derives fr…

Lithospheric P- and S-wave velocity models of the Sicilian area using WAM tomography: Procedure and assessments

2013

We present 3-D models of the P- and S-wave velocity distributions in the crust and uppermost mantle beneath Sicily, Calabria (Southern Italy), and surrounding submerged areas, obtained by tomographic inversion of traveltimes of regional body waves phases. Our method combines double-difference tomographic inversion with a post-processing procedure [Weighted Average Model method (WAM)]. This procedure was applied to a set of models consistent with the experimental data. We tested the ability of the WAM procedure to mitigate the uncertainty associated with the arbitrary nature of the many input parameters required for each inversion. The local reliability and resolution of the obtained models …

Comparative tests on different multi-electrode arrays using models in near-surface geophysics

2008

In this paper, the response of different synthetic models to geoelectrical multi-electrode surveys is studied. The models considered are related to two main problems, which are very common in geophysical research regarding hydrogeology and engineering. The first class of models represents buried walls, similar archaeological remains or remains of buried foundations; the other class corresponds to a sea-water intrusion of a fresh water aquifer, which is generally studied in hydrogeophysics. A set of 2D simulations, starting from the synthetic models, was carried out to compare the behaviour of the different arrays when acquiring measurements of electrical resistivity tomography. For each mod…

Integrated hydrogeochemical and geophysical surveys for a study of sea-water intrusion

2010

The CFTA Department of the University of Palermo in collaboration with ARPA SICILIA has carried out a study of the sea intrusion phenomenon in the aquifer between the cities of Marsala and Mazara del Vallo (south-western Sicily) using geophysical techniques (TDEM, ERT and MASW) and geochemical analysis of well water. The aim of the research was to optimize the acquisition techniques, data processing and data interpretation for the geometry reconstruction of aquifers, their characterization, and the determination of concentration of pollutants. The analysis of the geophysical results reveals the existence of very low resistivity values in correspondence of the area from the coastline to a ki…

L'impronta sonica di manufatti di interesse artistico e oggetti museali

2008

Viene presentata una nuova tecnica di indagine non invasiva, sicura e rapida, per l’identificazione univoca e per il monitoraggio dell’integrità di manufatti costituiti da materiali rigidi, quali vasellame, statue e in generale oggetti lapidei, metallici o lignei. La tecnica sfrutta la capacità degli oggetti di vibrare se sollecitati da una sorgente esterna artificiale e si basa sullo studio delle oscillazioni smorzate indotte. Così è possibile costruire una impronta sonica degli oggetti stessi, una sorta di DNA che li possa identificare senza alcun dubbio ed eventualmente possa anche valutarne lo stato di consistenza meccanica (o integrità) come monitoraggio nel tempo. L’applicazione della…

Geophysical study of an landslide in northern Sicily

2002

The San Fratello area in the Nebrodi Mountains (northern Sicily) is a region of high instability. It has suffered many devastating occurrences, which have hit and destroyed the village of San Fratello. At present the area is still subject to a high landslide risk. A series of geophysical surveys have been carried out with the aim of determining the thickness and dimensions of the landslide body as well as some tectonic features, in order to gain insight into the evolution of the landslide. The following geophysical techniques have been used: borehole seismic tomography, i.e. down-hole tomographic seismic soundings (DH TSS), time-domain electromagnetic (TDEM) soundings and georadar profiling…

Recognition of earthquake-induced damage in the Abakainon necropolis (NE Sicily): results from geo-morphological, geophysical and numerical analyses

2017

Seismotectonic activity and slope instability are a permanent threat in the archaeological site of Abakainon and in the nearby village of Tripi in NE Sicily. In recent times, signs of an ancient earthquake have been identified in the necropolis of Abakainon which dating was ascertained to the first century AD earthquake. The site is located on a slope of Peloritani Mts. along the Tindari Fault Line and contains evidence for earthquake-induced landslide, including fallen columns and blocks, horizontal shift and counter slope tilting of the tomb basements. In this paper, we used an integrated geomorphological and geophysical analysis to constrain the landslide. The research was directed to th…

Joint interpretation of constrained electrical and seismic models to study the landslide affecting the Agrigento Cathedral

2012

Integration of constrained electrical and seismic tomographies to study the landslide affecting the cathedral of Agrigento

2014

The Cathedral of Saint Gerland, located on the top of the hill of Agrigento, is an important historical church, which dates back to the Arab–Norman period (XI century). Unfortunately throughout its history the Cathedral and the adjacent famous Archaeological Park of the 'Valley of the Temples' have been affected by landslides. In this area the interleaving of calcarenites, silt, sand and clay is complicated by the presence of dislocated rock blocks and cavities and by a system of fractures partly filled with clay or water. Integrated geophysical surveys were carried out on the north side of the hill, on which the Cathedral of Agrigento is founded, to define lithological structures involved …

Geomorphological and geophysical investigations to study the landslide affecting the archaeological site of abakainon

2016

In recent years, a detailed archeoseismological investigation has been carried out in the necropolis of Abakainon in order to identify traces of an ancient earthquake. Although the identification of seismic damage was undoubtedly attributed to the 1st century AD earthquake, it was hypothesised that the level of damaging observed in the necropolis, as well as the counter slope tilting of the tomb basements may have also caused by a seismo-induced landslide, which produced locally an amplification of the seismic shaking. In order to identify the landslide, on which the Greek site lies, detailed geomorphological and geophysical surveys have been carried out. The research was directed to the ac…