0000000000104475
AUTHOR
Nicola Messina
Caratterizzazione geofisica dell’acquifero idrotermale dell’area di Panza (Ischia)
Gli obiettivi di questo lavoro sono quelli di ricostruire, con metodologie geofisiche integrate, le principali geometrie tettoniche ed idrogeologiche del territorio di Panza nell'isola di Ischia. La zona è stata scelta in quanto caratterizzata da un'intensa attività idrotermale e deformativa connessa con la presenza di un reservoir geotermico.
Geophysical study of the hydrothermal reservoir in the Panza area (Ischia, Italy)
The aim of the work is the reconstruction of the main geometric pattern and the characterisation with geophysical parameters of geological structures lying at small and medium depths in an area of the Ischia island (Italy), where a sensible hydrothermal activity is present.
Improvement of HVSR technique by cluster analysis
The Horizontal to Vertical Spectral Ratio (HVSR) technique, applied to ambient noise, is widely used to quickly estimate the fundamental frequency of a site. The HVSR technique is based on numerous assumptions about the propagation medium and the nature of the seismic noise, often hard to verified. In addition, in order to obtain reliable results, several acquisition and processing criteria must be respected. One of the most controversial aspects in the technique implementation are the reliable criteria for the identification in the microtremors signals of time windows appropriate for the calculation of the HVSR curves. Several authors suggest to remove spikes and transients because they br…
The integration of surface and subsurface stratigraphic data with HVSR measures for studies of seismic microzonation: the case of Oliveri (ME)
Because of its high seismic hazard the urban area of Oliveri has been subject of a study on seismic microzonation at first level (OPCM 3907/2010). The urban area develops on a large coastal plain made of Late Pleistocene and Holocene mixed fluvial/marine sediments, that mainly consist of silty sands and gravels. The eastern part of this plain is dominated by the alluvial deposits of the Elicona torrent. The coastal and alluvial sediments overlap a complexly deformed substrate made of Hercynian metamorphites (Aspromonte unit), the Capo d’Orlando Flysch, the Antisicilide Argille Scagliose and Pleistocene clays and calcarenites. This area is affected by high uplift rates as recently estimated …
Studi di base per il monitoraggio elettrotomografico dell’intrusione salina dell’acquifero di Petrosino
Integrated geophysical survey for 3D modelling of a coastal aquifer polluted by seawater
Geophysical surveys are carried out in the coastal area of Petrosino (south-western Sicily) to study the time evolution of seawater contamination of the coastal aquifer, probably increased due to human impact. The overexploitation of the aquifer, due to an intensive agricultural use has affected significantly the natural hydro-geochemical state of the basin. The study is based on a processing and integrated analysis of hydrogeological, geochemical and geophysical data. In particular in the last two years seasonal time-lapse electrical resistivity tomographies (ERT), new TDEM soundings and Multi-Analysis Surface Wave soundings (MASW) have been carried out. The interpretation of the total set…
The structure of a hydrothermal system from an integrated geochemical, geophysical, and geological approach: The Ischia Island case study
The complexity of volcano-hosted hydrothermal systems is such that thorough characterization requires extensive and interdisciplinary work. We use here an integrated multidisciplinary approach, combining geological investigations with hydrogeochemical and soil degassing prospecting, and resistivity surveys, to provide a comprehensive characterization of the shallow structure of the southwestern Ischia's hydrothermal system. We show that the investigated area is characterized by a structural setting that, although very complex, can be schematized in three sectors, namely, the extra caldera sector (ECS), caldera floor sector (CFS), and resurgent caldera sector (RCS). This contrasted structura…
Integration of HVSR measures and stratigraphic constraints for seismic microzonation studies: the case of Oliveri (ME)
Abstract. Because of its high seismic hazard the urban area of Oliveri has been subject of first level seismic microzonation. The town develops on a large coastal plain made of mixed fluvial/marine sediments, overlapping a complexly deformed substrate. In order to identify points on the area probably suffering relevant site effects and define a preliminary Vs subsurface model for the first level of microzonation, we performed 23 HVSR measurements. A clustering technique of continuous signals has been used to optimize the calculation of the HVSR curves. 42 reliable peaks of the H/V spectra in the frequency range 0.6–10 Hz have been identified. A second clustering technique has been applied t…
GEOCHEMICAL AND GEOPHYSICAL RESEARCH AIMED AT CHARACTERIZING THE HYDRO-GEOLOGICAL STRUCTURES OF A KARST FORMATION
Geochemical and geophysical research was effected in an area between the Madonia mountain range and the coast around the Rock of Cefalù, at the base of which there are a number of large-sized springs. The aim of the study was to reconstruct the buried hydro-geological structures that carry the waters from the Madonia Mountains to the areas along the coast where they surface. The Madonia Mountains are prevalently made up of carbonatic formations and terrigenous deposits of the Numidian Flysch. Outcrops of the Cozzo Terravecchia formation are also present, as are Messinian evaporitic deposits and recent detritic deposits of alluvial and marine origin. The Karst processes that develop in the l…
Integration of stratigraphic data with HVSR measures for studies of seismic microzonation: the case of Oliveri (ME)
The seismic microzoning is a technique of analysis of a territory which aims to recognize, at a small scale, the local geological and geomorphologic conditions that may significantly affect the characteristics of the seismic motion, generating stress on structures that could produce permanent and critical effects. In other words, this technique has the objective to predict and evaluate possible site effects as a result of an earthquake. The first phase of the seismic microzoning is the detailed partition of the territory in homogeneous areas with respect to the expected behavior of soils during an earthquake. The seismic micro-zoning is a tool for prevention and reduction of seismic risk pa…