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Geological evidence for paleotsunamis along eastern Sicily (Italy): an overview  [PDF]
P. M. De Martini,M. S. Barbano,D. Pantosti,A. Smedile
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2012, DOI: 10.5194/nhess-12-2569-2012
Abstract: We present geological evidence for paleotsunamis along the ~230 km-long coast of eastern Sicily (Italy); combining this information with historical data, we reconstruct a unique history of tsunami inundations. We integrate data on 38 paleotsunami deposits (from fine sand layers to boulders) collected at 11 sites (one offshore). The geological data record traces of large tsunamis which have occurred during the past 4 millennia. Chronological constrains include 14C, 210Pb and 137Cs, OSL and tephrochronology. When compatible, the age of the paleotsunami deposits is associated to historical events, but it is also used to highlight unknown tsunamis. Average tsunami recurrence interval (between 320 and 840 yr) and minimum inland tsunami ingressions (often greater than the historical ones) were estimated at several sites. On the basis of this work, the tsunami catalogue is implemented by two unknown tsunamis which occurred during the first millennium BC and by one unknown regional tsunami, which occurred in 650–770 AD. By including this latter event in the eastern Sicily catalogue, we estimate an average recurrence interval for strong tsunamis of ca. 385 yr. Comparison and merging of historical and geological data can definitely contribute to a better understanding of regional and local tsunami potential and provides robust parameters to be used in tsunami hazard estimates.
Integrated geophysical survey for the geological structural and hydrogeothermal study of the North-western Gargano promontory (Southern Italy)
M. Loddo,R. Quarto,D. Schiavone
Annals of Geophysics , 1996, DOI: 10.4401/ag-3962
Abstract: A multimethodological geophysical survey was performed in the north-western part of the Gargano promontory to study the geological structural setting and the underground fluid flow characteristics. The area has a complex tectonics with some magmatic outcrops and shallow low-enthalpy waters. Electrical, seismic reflection, gravimetric and magnetic surveys were carried out to reconstruct the geological structures; and in order to delineate the hydrogeothermal characteristics of the area, the self-potential survey was mainly used. Moreover magnetic and self-potential measurements were also performed in the Lesina lake. The joint three-dimensional interpretation of the geophysical data disclosed a large horst and graben structure covering a large part of the area. In the central part of the horst a large ramified volcanic body was modelled. The models show some intrusions rising from it to or near to the surface. The main structures are well deep-seated in the Crust and along them deep warm fluids rise as the SP data interpretation indicates.
Integrated geophysical investigations for seismic zoning in a coastal area of Northern Sicily  [cached]
Annals of Geophysics , 1982, DOI: 10.4401/ag-4677
Abstract: The area, about 225 km2 large, ranging from the Eleuterio river to the S. Leonardo river on the northern coast of Sicily, has suffered many earthquakes in the past centuries and has for many years recognized as a seismic area. This paper presents a set of integrated geophysical studies carried out in that area, including: i) a statistical study of the past earthquakes in order to define the earthquake risk (PGV or PGA risk), ii) a set of laboratory density measurements carried out on samples of rocks (82 samples), Hi) a shallow refraction investigation (290 profiles) in order to study the mechanical properties of such rocks, iv) a deep geoelectrical investigation (200 VES) in order to reconstruct the main geological features with particular regard to the geometrical distribution of the elastic and plastic formations which have been piled up during the complex overthrusting of the Sicilian chain, and v) a detailed study of the possible amplifications of the groundmotions due to the geometry and the mechanical characteristics of the shallow and intermediate rocks. The results, combined wih the knowledge of the regional tectonic features and the locations of the involved seismogenetic volumes, allow the formation of a picture of the seismic responses and the connected seismic risk
Recent deeper geophysical results better account for the tectonics in the Italian area  [cached]
C. Morelli
Annals of Geophysics , 1997, DOI: 10.4401/ag-3864
Abstract: Results from extended DSS profiles (1956-1986) in Italy and surrounding land and sea areas offer good constraints for other geophysical and geological data. Integrated interpretations outline the main tectonic features. Collisional tectonics is predominant in the Alps, for which the Adriatic plate acted as hinterland against the European plate foreland. Main results: W-wards, NW- and N-wards oriented overthrusting on the European crust, bending of the lower European crust, European Moho to 70 km depth with the Adriatic mantle indented above, crustal doubling (Adriatic over the European one). In the Apennines, on the contrary, the Adriatic plate acted as a foreland, against the overthrusts generated by the Tuscanian and Tyrrhenian mantellic bodies, heated, elevated and migrated NE-wards and SE-wards, respectively. Also the Adriatic plate bends under this load-centripetally towards the Tyrrhenian sea, so that the Adriatic Moho from 35 km depth is presumed to descend through a flexure till 40-50 km below the Tuscanian and Tyrrhenian land areas. The external peri-Apenninic area is still in compression and includes thick sedimentary basins, from the Po-plain to Sicily. The internal area is in extension, overlapped by thin, stretched crusts of Ligurian and Tyrrhenian origin, whose remnants occupy most of both seas areas, with two areas of oceanic crust in the SE-Tyrrhenian. Rifting and opening is in action also in the Ligurian Sea and Sicily Strait.
Emergence and Phylodynamics of Citrus tristeza virus in Sicily, Italy  [PDF]
Salvatore Davino, Anouk Willemsen, Stefano Panno, Mario Davino, Antonino Catara, Santiago F. Elena, Luis Rubio
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0066700
Abstract: Citrus tristeza virus (CTV) outbreaks were detected in Sicily island, Italy for the first time in 2002. To gain insight into the evolutionary forces driving the emergence and phylogeography of these CTV populations, we determined and analyzed the nucleotide sequences of the p20 gene from 108 CTV isolates collected from 2002 to 2009. Bayesian phylogenetic analysis revealed that mild and severe CTV isolates belonging to five different clades (lineages) were introduced in Sicily in 2002. Phylogeographic analysis showed that four lineages co-circulated in the main citrus growing area located in Eastern Sicily. However, only one lineage (composed of mild isolates) spread to distant areas of Sicily and was detected after 2007. No correlation was found between genetic variation and citrus host, indicating that citrus cultivars did not exert differential selective pressures on the virus. The genetic variation of CTV was not structured according to geographical location or sampling time, likely due to the multiple introduction events and a complex migration pattern with intense co- and re-circulation of different lineages in the same area. The phylogenetic structure, statistical tests of neutrality and comparison of synonymous and nonsynonymous substitution rates suggest that weak negative selection and genetic drift following a rapid expansion may be the main causes of the CTV variability observed today in Sicily. Nonetheless, three adjacent amino acids at the p20 N-terminal region were found to be under positive selection, likely resulting from adaptation events.
Landslide susceptibility assessment in the Peloritani Mts. (Sicily, Italy) and clues for tectonic control of relief processes
G. De Guidi,S. Scudero
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2013, DOI: 10.5194/nhess-13-949-2013
Abstract: Many destructive shallow landslides hit villages in the Peloritani Mountains area (Sicily, Italy) on 1 October 2009 after heavy rainfall. The collection of several types of spatial data, together with a landslide inventory, allows the assessment of the landslide susceptibility by applying a statistical technique. The susceptibility model was validated by performing an analysis in a test area using independent landslide information, the results being able to correctly predict more than 70% of the landslides. Furthermore, the susceptibility analysis allowed the identification of which combinations of classes, within the different factors, have greater relevance in slope instability, and afterwards associating the most unstable combinations (with a short–medium term incidence) with the endogenic processes acting in the area (huge regional uplift, fault activity). Geological and tectonic history are believed to be key to interpreting morphological processes and landscape evolution. Recent tectonic activity was found to be a very important controlling factor in landscape evolution. A geomorphological model of cyclical relief evolution is proposed in which endogenic processes are directly linked to superficial processes. The results are relevant both to risk reduction and the understanding of active geological dynamics.
First report of Vryburgia amaryllidis (Bouché) (Homoptera, Pseudococcidae) on Agapanthus sp. in Sicily, Italy
Santi Longo
Journal of Entomological and Acarological Research , 2012, DOI: 10.4081/jear.2012.e3
Abstract: The lily mealybug, Vryburgia amarillidis (Bouché) (Homoptera, Pseudococcidae) was detected on containerized Agapanthus sp. plants in Sicily, Italy. The morphological characteristics of the Sicilian populations of this pest are described.
Integrated geophysical and geological investigations applied to sedimentary rock mass characterization  [cached]
M. T. Carrozzo,G. Leucci,S. Margiotta,F. Mazzone
Annals of Geophysics , 2008, DOI: 10.4401/ag-3044
Abstract: The Salento Peninsula (south-eastern Italy) is characterized by sedimentary rocks. The carbonatic nature of the rocks means they are affected by karst phenomena, forming such features as sinkholes, collapsed dolines and caverns, as a result of chemical leaching of carbonates by percolating water. The instability of these phenomena often produces land subsidence problems. The importance of these events is increasing due to growing urbanization, numerous quarries affecting both the subsoil and the surface, and an important coastline characterized by cliffs. This paper focuses on geological and geophysical methods for the characterization of soft sedimentary rock, and presents the results of a study carried out in an urban area of Salento. Taking the Q system derived by Barton (2002) as the starting point for the rock mass classification, a new approach and a modification of the Barton method are proposed. The new equation proposed for the classification of sedimentary rock mass (Qsrm) takes account of the permeability of the rock masses, the geometry of the exposed rock face and their types (for example, quarry face, coastal cliff or cavity), the nature of the lithotypes that constitute the exposed sequence, and their structure and texture. This study revises the correlation between Vp and Q derived by Barton (2002), deriving a new empirical equation correlating P-wave velocities and Qsrm values in soft sedimentary rock. We also present a case history in which stratigraphical surveys, Electrical Resistivity Tomography (ERT), and seismic surveys were applied to in situ investigations of subsidence phenomena in an urban area to estimate rock mass quality. Our work shows that in the analysis of ground safety it is important to establish the rock mass quality of the subsurface structures; geophysical exploration can thus play a key role in the assessment of subsidence risk.
Buried archeological remains connected to the Greek-Roman harbor at Tindari (north-east Sicily): results from geomorphological and geophysical investigations
Carla Bottari,Stefano Urbini,Marcello Bianca,Maria D'Amico
Annals of Geophysics , 2012, DOI: 10.4401/ag-4656
Abstract: In recent years, detailed geoarcheological investigations have been carried out to search for traces of the ancient Tindari harbor (north-east Sicily, Italy). A digital terrain model supported the hypothesis that 2,000 yr ago the Oliveri Basin was a suitable landing place that was protected from prevailing winds. This model was generated from uplift data, sea level changes, historical cartographic data and three-dimensional reconstruction of the sedimentary succession of the cover. The present position of some historical buildings represent an archeological marker of the shoreline progression. Recent excavations during the construction of the Messina-to-Palermo motorway brought to light some portions of an ancient archeological complex. The thickness of the walls and the volume of the collected archeological material suggests dating between the 1st century BC and the 4th century AD. After that time, heavy environmental changes due to human activities in the area led to inaccurate underestimation of the role of Tindari harbor in the past. A geophysical investigation was carried out in the area surrounding the archeological complex to search for new buried structures related to the ancient settlement, and to be open to any results of the paleotopographic reconstruction of the area. The applied geophysical techniques included passive seismic and ground-penetrating radar. This survey indicates the presence of buried structures, such as walls and floors, that probably belong to a Roman villa. Furthermore, it defines the depth of the Holocene sedimentary cover of the Oliveri coastal plain, which strengthens the hypothesis formulated for its morphological evolution.
Geophysical surveying of slopes affected by debris flows: the case of S. Felicea Cancello (Caserta, Southern Italy)
V. Chiessi,M. D'Orefice,S. Superbo
Annals of Geophysics , 2003, DOI: 10.4401/ag-3473
Abstract: This paper contains the results of a series of geophysical investigations carried out on the largest debris flow to have taken place in Tavernole, S. Felice a Cancello (Caserta, Southern Italy). The landslide occurred in concurrence with other catastrophic events in the Sarno Mountains in May 1998. This research project is part of a series of geological, geomorphological and geotechnical studies whose purpose is to improve the knowledge of this type of phenomenon. The project also tested and compared various survey methods in the sample area of S. Felice a Cancello. Geophysical surveying allowed us to collect information regarding the physical features and thickness of the materials affected by landslide phenomena and to verify the applicability and effectiveness of the various indirect surveying methods adopted. The preliminary results of the study enabled us to generate a series of suggestions which could prove useful in formulating the correct approach to this type of problem to be adopted in ordinary professional practice. These indications concerned the type of geophysical surveying to be conducted and, where applicable, the means of implementation. In general, seismic refraction was found to be the best technique for collecting information on the area studied.
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