Search results for "Tectonic"
showing 10 items of 470 documents
Sedimentary basins evolution and olistoliths formation: The case of Carpathian and Sicilian regions
2012
Abstract Comparative research carried out within two different basins, one in the Carpathians of Poland (Late Jurassic to Early Miocene) and another in the Apenninic-Maghrebian mountain chain of Sicily (Triassic-Miocene), indicate significant similarity not only in their evolution but also in the sedimentary features of horizons with olistoliths. The olistolith-bearing units are genetically related to stages of tectonic evolution and are independent of the size of the basins and of duration of these stages. However, the observed differences in composition and size of olistoliths suggested, among the others relationship with the size of source areas and thickness of their sedimentary cover.
Tectono-stratigraphic evolution of a basin generated by transpression: the case of the Early Pliocene Lascari Basin (northern Sicily)
2011
Integrated stratigraphy and structural analysis carried out in the Madonie Mts. (Northern Sicily) is aimed to the description of a syn-sedimentary tectonic event, recorded in a small infra-pliocene basin restricted to the Lascari Syncline core. The onset and evolution of the basin was driven by transpressive tectonics, generating a lens-shaped, deep and narrow tectonic depression, bounded by steep and high, tectonically controlled slopes, also reflected in the present-day topography of the area. During the genesis of the basin, the tectonic control interferes with a dramatic sea level oscillation during the Messinian-Early Pliocene time interval. In this paper, the syn-tectonic deposits of …
Friction of Shear-Fracture Zones
2017
A shear fracture of brittle solids under compression undergoes a substantial evolution from the initial microcracking to a fully formed powder-filled shear zone. Experiments covering the entire process are relatively easy to conduct, but they are very difficult to investigate in detail. Numerically, the large strain limit has remained a challenge. An efficient simulation model and a custom-made experimental device are employed to test to what extent a shear fracture alone is sufficient to drive material to spontaneous selflubrication. A “weak shear zone” is an important concept in geology, and a large number of explanations, specific for tectonic conditions, have been proposed. We demonstra…
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…
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…
NEW TECHNOLOGIES FOR THE DOCUMENTATION AND PRESERVATION OF THE MAYA CULTURAL HERITAGE. THE PALACE OF THE GOVERNOR AT UXMAL (YUCATÁN, MEXICO)
2020
[EN] One of the major challenges currently facing the architectural and archaeological heritage in subtropical World Heritage sites is its preventive conservation. Many of these sites are vulnerable to the adverse impacts of natural disasters and climate change. The risk is compounded by the fact that several of them are among the most iconic places in the world, and so they also face the threat of the excessive growth of visitors. What is more, in earlier times many were restored with unsuitable materials or using inappropriate techniques which have heightened the risk they face today. However, thanks to the new digital technologies of architectural documentation involving the use of laser…
Advanced radar-interpretation of InSAR time series for mapping and characterization of geological processes
2011
Abstract. We present a new post-processing methodology for the analysis of InSAR (Synthetic Aperture Radar Interferometry) multi-temporal measures, based on the temporal under-sampling of displacement time series, the identification of potential changes occurring during the monitoring period and, eventually, the classification of different deformation behaviours. The potentials of this approach for the analysis of geological processes were tested on the case study of Naro (Italy), specifically selected due to its geological setting and related ground instability of unknown causes that occurred in February 2005. The time series analysis of past (ERS1/2 descending data; 1992–2000) and current…
Tectonique salifère et déformation gravitaire de la marge passive sud-gabonaise de l'Albien au Turonien (secteur de Mayumba) Salt tectonic and thin-s…
2003
International audience; L'observation de données sismiques de bonne qualité relatives à la marge passive sud-gabonaise montre : 1) les structures extensives, compressives et inversives albo-turoniennes, associées à la tectonique gravitaire au-dessus du niveau salifère Ezanga (Aptien supérieur). D'est en ouest, ces structures synsédimentaires, d'échelle kilo-métrique, sont en blocs basculés, en anticlinaux, en roll over, en " carapace de tortue ", de nouveau en plis et failles inverses, et enfin en langues de sel déversées vers l'ouest. 2) l'influence du niveau salifère sur la structuration gravitaire ; 3) l'héritage passif syn-rift au niveau des zones hautes anté-salifères qui favorisent la…
First combined flux chamber survey of mercury and CO2 emissions from soil diffuse degassing at Solfatara of Pozzuoli crater, Campi Flegrei (Italy): M…
2014
Abstract There have been limited studies to date targeting gaseous elemental mercury (GEM) flux from soil emission in enriched volcanic substrates and its relation with CO 2 release and tectonic structures. In order to evaluate and understand the processes of soil–air exchanges involved at Solfatara of Pozzuoli volcano, the most active zone of Campi Flegrei caldera (Italy), an intensive field measurement survey has been achieved in September 2013 by using high-time resolution techniques. Soil–air exchange fluxes of GEM and CO 2 have been measured simultaneously at 116 points, widely distributed within the crater. Quantification of gas flux has been assessed by using field accumulation chamb…
Sequence of deformation in the sicilidi units (northern sicilian chain)
2004
The foredeep deposits of Northern Sicily, indicated as Sicilidi units, have undergone different deformations' since Oligocene time. The resulting tectonic Structures, analysed in several outcrops in the Eastern Madonie Mts, are 1 cm-to- 100 m in scale and are similar to the larger structures forming the Sicily belt, allowing for scale extrapolation. Also the overprinting relationships of the minor structures recorded in the so-called Tufiti di Tusa reflect the sequence of fault activation which determined the present-day geometry of the tectonic units, suggesting that the tectonic evolution of the foreland basin developed during the stacking of the Maghrebide fold-and-thrust belt. The overp…