A three-dimensional back-analysis of the collapse of an underground cavity in soft rocks

Abstract The assessment of stability of man-made underground caves, excavated in the past and later on abandoned, represents a serious challenge for land and urban planning operations, especially for the areas of possible interaction of the caves with overlying structures and infrastructures. Several areas of Southern Italy are characterized by the presence of abandoned underground quarries for the extraction of soft calcarenite rocks, which now threatens the overlying environment due to the risk of collapse and the consequent generation of sinkholes. This work presents a back-analysis of a sinkhole occurred in 2011 in the town of Marsala, caused by the collapse of an underground quarry, as…

Quaternary eustatic fluctuations and biochronology of vertebrate-bearing deposits correlated with marine terraces in Sicily

Extensive field mapping in Sicily in the frame of the CARG Project

Rilievi geologici finalizzati alla compilazione di carte geologiche in Sicilia nord-occidentale (Progetto CARG) Vengono descritti i risultati del rilevamento di numerosi fogli geologici a scala 1:50.000 ubicati nella Sicilia settentrionale (dalle Isole Egadi fino ai Monti delle Madonie), eseguito nel quadro del Progetto CARG. I rilievi sul terreno sono stati integrati con i dati di sottosuolo provenienti da profili sismici a riflessione e perforazioni profonde. I risultati ottenuti offrono un quadro a scala regionale dell’assetto stratigrafico-strutturale di uno dei settori più complessi della Catena Siciliano-Maghrebide. Sono state ricostruite le successioni stratigrafiche dei paleodomini …

Long-term earthquake potential of active faults by using coastal and off-shore geological and morphological indicators

Seismogenic fault models and active deformation ones coupled with models of both earthquake rate and earthquake probability were recently used in a time-independent modelling. The integration of models allows to estimates the magnitude, location, and likelihood of potentially damaging earthquake ruptures in regions with high natural seismic hazard. Improvements of these models imply the recognition of the spatial geometry of the larger, active faults, deemed to be the source of the most damaging future earthquakes. However, identifying active faults and calculating their geologic slip rates for deriving earthquake rates are not easy tasks in regions inaccessible to direct field studies like…

Osgillazioni eustatiche, biocronologia dei depositi continentali quaternari e neotettonica nella Sicilia nord-occidentale (penisola di San Vito lo Capo - Trapani)

Vengono presentati i risultati di uno studio interdisciplinare condotto nella Penisola di San Vito lo Capo, Sicilia nord - occidentale. In questa area i terreni quaternari sono rappresentati da depositi marini e di spiaggia distribuiti a varie quote e da depositi continentali contenenti resti di vertebrati. Questi terreni si rinvengono all'interno di solchi e grotte marine, dove sono state riconosciute anche fasce a fori di litodomi, o costituiscono corpi sedimentari che giacciono sopra superfici di abrasione marina. Le associazioni a mammiferi presenti in tali terreni appartengono al complesso faunistico a Elephas falconeri del primo Pleistocene medio, al complesso a Elephas mnaidriensis d…

The great landslide at Portella Colla (Madonie, Sicily)

The South Western area of the Madonie Mountains is affected by large landslides; the major one developed starting from Portella Colla down to the Imera Settentrionale river, for a maximum length of about 6.2 km in a NE-SW direction. The study of the landslide, with the aim of reconstructing the geological, geomorphological and evolutionary aspects, has been carried out using integrated methodologies, including some geophysical investigations (in particular geoelectrical prospecting). The landslide is complex and characterized by superficial and deep gravitational deformations. The movement began in the Upper Pliocene and it is still active. The origin and evolution of the landslide are link…

Surface denudation rate of gypsum in Sicily

Studies on surface denudation rate of karst rocks were carried out for many years with different methods, although researches on limestones are much more numerous than those on gypsum. In Sicily the most large and complete Messinian evaporite succession of Gruppo Gessoso – Solfifero outcrops and since 1993-1994 surface denudation measurements were performed on different types of gypsum by the Micro-Erosion Meter (M.E.M.) method. MEM stations were placed on natural sites representing different lithological features of gypsum outcrops of the Island: 1) selenite gypsum with centimetre-sized crystals; 2) selenite gypsum with sub-centimetre crystals; 3) gypsum arenite; 4) microcrystalline gypsum…

Genetic models of poljes in Sicily

Geomorphological and geological studies have been carried out to contribute to the recognition of controlling causes and to the definition of genetic models for poljes of Sicily. A polje is a kilometric closed depression developed mainly on karst rocks, with a conspicuously flat and alluviated bottom affected by intermittent flooding. A polje is usually characterised by relatively steep slopes enclosing an almost perfectly horizontal floor, caused by lateral solution planation related to flooding events. The origin of a polje is due to dissolution of the land surface, although geological structure generally influences its genesis. These large depressions are often elongated according to the…