UNINA

The paper proposes a method to evaluate the potential for electric power production at any site of possible geothermal interest. Accounting for geological data of the reservoirs, the method allows the computation of the available electrical power of the investigated site. Electrical energy production from geothermal sources is realized through different techniques, such as single flash and double flash, dry steam, and binary ORC plants. The technique chosen to be the most productive is determined by analyzing a specific range of geofluid properties, mainly temperature and pressure. Moreover, each plant typology has a global efficiency that may be correlated to geofluid enthalpy by empiric relations available in literature. The proposed evaluation method brings together all these correlations, yielding the power availability from a geosource, once its temperature and pressure are known. The method takes as input the geofluid available flow rate, its pressure, temperature and non-condensable gas content. It defines the best plant option from these parameters, calculates its global efficiency and finally returns the actual available power. For sites of geothermic interest, such as the volcanic island of Ischia in Southern Italy, the results of the application of this new method clearly highlight the most suitable zones for power plants installations.

Integrated geological, geodetic and marine geophysical data provide evidence of active deformation insouth-western Sicily, in an area spatially coincident with the macroseismic zone of the destructive 1968Belice earthquake sequence. Even though the sequence represents the strongest seismic event recordedin Western Sicily in historical times, focal solutions provided by different authors are inconclusive onpossible faulting mechanism, which ranges from thrusting to transpression, and the seismogenic sourceis still undefined. Interferometric (DInSAR) observations reveal a differential ground motion on a SW–NEalignment between Campobello di Mazara and Castelvetrano (CCA), located just west of the maximummacroseismic sector. In addition, new GPS campaign-mode data acquired across the CCA alignment doc-uments NW–SE contractional strain accumulation. Morphostructural analysis allowed to associate thealignment detected through geodetic measurements with a topographic offset of Pleistocene marine sed-iments. The on-land data were complemented by new high-resolution marine geophysical surveys, whichindicate recent contraction on the offshore extension of the CCA alignment. The discovery of archaeo-logical remains displaced by a thrust fault associated with the alignment provided the first likely surfaceevidence of coseismic and/or aseismic deformation related to a seismogenic source in the area. Resultsof the integrated study supports the contention that oblique thrusting and folding in response to NW–SEoriented contraction is still active. Although we are not able to associate the CCA alignment to the 1968seismic sequence or to the historical earthquakes that destroyed the ancient Greek city of Selinunte,located on the nearby coastline, our result must be incorporated in the seismic hazard evaluation of thisdensely populated area of Sicily.

The aim of this paper is to recognize and map the Somma-Vesuvius volcano landslide-prone areas by means of multi-disciplinary terrain analysis and classification; in detail, high-resolution DTM of landslides areas occurred over long time periods, remote sensing, and geophysical and geomorphological data are presented for assessing hydrogeological hazard parameters of this volcanic district.

The aim of this paper is to recognize and map the Somma-Vesuvius volcano landslide-prone areas by means of multi-disciplinary terrain analysis and classification; in detail, high-resolution DTM of landslides areas occurred over long time periods, remote sensing, and geophysical and geomorphological data are presented for assessing hydrogeological hazard parameters of this volcanic district. The Somma-Vesuvius volcano, due to its explosive volcanism and the dense urbanization of the surrounding area with a population exceeding 650,000, is one of the most dangerous active volcanoes of the world. The main hazard of the perivolcanic area is associated to effusive eruptions and explosive Plinian and sub-Plinian eruptions, alternated to long-lasting quiescence periods. Moreover, additional hazard is related to lahars: flows of unconsolidated debris and water that typically include fragments of volcanic origin, colluvium, and soil. The features of lahars can range from debris flow to hyperconcentrated flow. The most important lahars phenomena of the Somma-Vesuvius occurred with the main historical eruptions of 79 A.D., 472 A.D., and 1631 (Mastrolorenzo et al. 2002; Rosi et al. 1993; Rosi et al. 1996). Recently, remobilization of the pyroclastic cover has produced several debris flows and alluvial phenomena that invaded the surrounding plains affecting towns and roads. Our methodological approach is based on landslides data recognizing and mapping both from geological maps, papers, historical chronicles, and from aerial photos, orthophoto, and available DTM image analysis of the Somma-Vesuvius complex. Through detailed study of this material the main landslides depositional areas have been surveyed; moreover, other geophysical and geomorphological parameters have been considered jointly with the landslides occurrence in order to correlate and interpret the soil movements phenomena. The analysis of several space-time series of data, together with the updated territorial information has been carried out through the Geographic Information System (GIS) (software ArcGIs 9.3), in order to store, manage and process large amount of spatial data. Finally, the achievement of landslide hazard high-resolution mapping of the Somma-Vesuvius volcano is performed in this paper through investigation of the flowslides deposits (lahar) of this area (Di Crescenzo et al. 2008). Actually, the recent heavy urbanization of landslide-prone areas has increased their vulnerability, consequently buildings and infrastructure could be seriously damaged and safety of the people endangered (Davoli et al., 2001). Therefore the obtained maps are necessary for identifying the future inundation areas and for evaluating the possible hydrogeological risk scenarios.