A Natural Laboratory for Offshore Paleotsunami Studies: The Augusta Bay (Eastern Sicily, Italy)

The recent results obtained from a 6.7 long piston core (MS06), collected 2.3 km offshore Augusta at a water depth of 72 m and made of an almost homogeneous dark gray mud dated back to the last 4500 yrs, stimulated our curiosity in searching for other similar signatures. In fact, quantitative micropaleontological analysis of benthic foraminifera assemblages highlighted 12 anomalous intervals, marked by peaks with high percentages of displaced epiphytic specimens and an increase in the sandy component. These anomalies were generally accompanied by a significant amount of Posidonia remnants, a localized concentration of molluscs and organic-rich bands. Thus, the twelve anomalous peaks were interpreted as the primary effect of tsunami waves backwash). Moreover, five out of the twelve anomalous layers were embedded in age intervals encompassing the dates of major tsunamis that hit eastern Sicily (1908, 1693, and 1169) and the broader Eastern Mediterranean (AD 365 Crete and Santorini at about BP 3600). Seven additional cores were sampled from the northern part of the Augusta Bay, along a transect 60 to 110 m of water depth, to retrieve the details of the MS06 sequence uppermost part. Four out of the seven new cores were selected and studied. Preliminary dating suggests that the sampled sequence spans ca. 400-500 yrs. Moreover, physical properties, ITRAX Xray fluorescence (XRF) and grain size analyses point out the presence of a peculiar interval made of Posidonia remnants, coarse sand and shell debris on the two cores closer to the shore. The two faroff cores seem to be more homogenous but a few thin sandy lenses enriched of Posidonia remnant were also recognized. Further detailed micropaleontological analysis and corroboration with instrumental data are still in progress and will help in discriminating single events potentially related to tsunami backwash

Unicentric or multicentric castleman disease? A case report of a pelvic intraperitoneal mass in a middle aged woman

Castleman Disease is a lymphoid disorder characterized by the presence of an enlarged or abnormal lymph node/lymphatic tissue. The disease is classified into unicentric or multicentric variants. The unicentric form is a benign disorder that is usually asymptomatic and consists of a single lymphoid mass that is predominantly located in the mediastinum, but can also rarely develop in the neck or abdomen. The multicentric type involves more than one lymphatic station and is related to the presence of type B symptoms (fevers, night sweats and weight loss), HIV/HHV8 infection and increased serum IL-6 levels. We present the case of an unusual pelvic intraperitoneal manifestation of Castleman Disease in a 52-year-old caucasian woman who showed clinical, radiological, histological and laboratory findings common to both Unicentric and Multicentric Castleman Disease

Combining inland and offshore paleotsunamis evidence: the Augusta Bay (eastern Sicily, Italy) case study

Offshore and inland geological evidence for multiple tsunami inundations was found in the Augusta Bay area: (1) the main local historical tsunamis (1908, 1693, 1169), (2) two far-generated tsunamis (i.e. Crete 365AD and Santorini, 3600 BP), and (3) seven unknown tsunamis). Average tsunami recurrence intervals from inland and offshore investigations of about 550 and 320 yr, respectively were obtained for the past 4 ka. The history of paleotsunamis from the marine record appears to be as complete as the historical one for the past millennium, yielding an average tsunami recurrence interval of 250 yr for the Augusta Bay. Geological data allow also estimating a minimum tsunami inundation distance of 530m and a minimum run-up of 5 m. The marine record contains evidence for more paleotsunamis with respect to the inland one because of continuous sedimentation and better preservation of stratigraphy in the offshore with respect to coastal areas, which are commonly affected by intermittent-erosion and sedimentation and anthropic activities. This work shows that the integration of geological and historical data can provide critical information regarding the extent and age of tsunamis of the past (e.g. inundation distance, age, and frequency), which is of immediate relevance for tsunami hazard assessment

Microbial Biofilms Along a Geochemical Gradient at the Shallow-Water Hydrothermal System of Vulcano Island, Mediterranean Sea

Shallow water hydrothermal vents represent highly dynamic environments where strong geochemical gradients can shape microbial communities. Recently, these systems are being widely used for investigating the effects of ocean acidification on biota as vent emissions can release high CO2 concentrations causing local pH reduction. However, other gas species, as well as trace elements and metals, are often released in association with CO2 and can potentially act as confounding factors. In this study, we evaluated the composition, diversity and inferred functional profiles of microbial biofilms in Levante Bay (Vulcano Island, Italy, Mediterranean Sea), a well-studied shallow-water hydrothermal vent system. We analyzed 16S rRNA transcripts from biofilms exposed to different intensity of hydrothermal activity, following a redox and pH gradient across the bay. We found that elevated CO2 concentrations causing low pH can affect the response of bacterial groups and taxa by either increasing or decreasing their relative abundance. H2S proved to be a highly selective factor shaping the composition and affecting the diversity of the community by selecting for sulfide-dependent, chemolithoautotrophic bacteria. The analysis of the 16S rRNA transcripts, along with the inferred functional profile of the communities, revealed a strong influence of H2S in the southern portion of the study area, and temporal succession affected the inferred abundance of genes for key metabolic pathways. Our results revealed that the composition of the microbial assemblages vary at very small spatial scales, mirroring the highly variable geochemical signature of vent emissions and cautioning for the use of these environments as models to investigate the effects of ocean acidification on microbial diversity

Geological Evidence of Paleotsunamis at Torre degli Inglesi (northeast Sicily)

Two layers of fine sand of marine origin occur in a sequence of organic rich colluvia in an archaeological excavation at Torre degli Inglesi, on Capo Peloro, northeast Sicily. Stratigraphic and micropaleontologic analyses support the hypothesis that these layers are related to deposition due to paleotsunami waves. Their ages are constrained both with radiocarbon and archaeological datings. The age of the oldest layer is coincident with the 17 A.D. earthquake that hit Reggio Calabria but for which no tsunami was previously reported. The age of the youngest layer can be only constrained in the range 3rd– 19th century and is tentatively associated to the 6 Feb. 1783 event

Geology of the lower Belice River valley, epicentral area of the M > 5 1968 seismic sequence (south-western Sicily, Italy)

We present a new 1:25,000-scale geological map of the lower Belice River valley, the area struck by the M > 5.0 devastating 1968 seismic sequence, whose seismic source and seismotectonic framework are still controversial. The map, utilizing dating methods and traditional field survey approaches integrated by high-resolution topography, provides an unprecedented detail and precision on the spatial distribution and on the compressional growth geometries of the prominent sedimentary sequence. This map, supported by the first recognition of an on-shore Chibanian-Calabrian deposition and by identifying a flight of marine terraces, offers new insights on the long-lasting syn-depositional tectonic forces up to late-Pleistocene-Holocene times. Such tectonic forces may take part in the regional ongoing deformational phase, prompting detailed studies on the potential seismic sources affecting the area

Historical, archeological and geological records of strong earthquakes at Capo Peloro (southern Italy)

During the 4th century AD southern Calabria and eastern Sicily were hit by an earthquake documented by archaeoseismic analyses, which was interpreted by Guidoboni et al. (2000) as the predecessor of the well-know 1908 earthquake, located in Messina Strait, whereas Galli and Bosi (2002) interpreted this event as the precedessor of the 1783 earthquake. The purpose of this paper is to find further evidence of these earthquakes in Messina area by a multidisciplinary study aimed to recognize and date historical and paleo-earthquakes. For this goal we have analyzed historical, archaeological and geological information of excavations performed at Capo Peloro near the Torre del Faro village (Fig. 1) in the Torre degli Inglesi (English Tower), built on an abandoned Roman tower

A unique 4000 year long geological record of multiple tsunami inundations in the Augusta Bay (eastern Sicily, Italy)

We present the geological evidence for a 4000 year long record of multiple tsunami inundations along the coast of the Augusta Bay (eastern Sicily)and discuss its implications. The research was carried out through a multi-theme approach which benefited from an extraordinarily long historical record that we used to guide detailed geomorphologic and geologic surveys, coring campaigns and laboratory analyses. Two sites, named the Augusta Hospital and Priolo Reserve, were selected and investigated in detail along the 25 km-long coastline of Augusta Bay. We found evidence for six (possibly seven) tsunami deposits; three of them may be tentatively associated with the 1693 and 365 AD Ionian Sea historical tsunamis and the ~3600 BP Santorini event. The other three (possibly four) deposits are evidence for unknown paleo-inundations dated at about 650–770 AD, 600–400 BC and 975–800 BC (at Augusta Hospital site), and 800–600 BC (at Priolo Reserve site). We use these ages to extend further back the historical record of tsunamis available for this coastal area. The exceptional number of tsunami deposits found with this study allowed us to derive an average geologic tsunami recurrence interval in the Augusta Bay of about 600 years for the past 4 ka. Conversely, the historical tsunami data for the past millennium suggest an average tsunami recurrence interval of about 250 years. This difference in the average recurrence intervals suggests that only the strongest inundations may leave recognizable geological signatures at the investigated sites (i.e. the evidence for the 1908 and 1169 tsunamis is missing) but also that the geomorphological setting of the site and its erosional/depositional history are critical aspects for the data recording. Thus, an average recurrence interval derived from the geological record should be considered as a minimum figure. The identification and age estimation of tsunami deposits represent a new and independent contribution to tsunami scenarios and modeling for coastal hazard assessment in Civil Protection applications. Furthermore, our study cases provide new elements on tsunami deposit recognition related to exceptionally large events that occurred in the Aegean Sea

Geological evidence for paleotsunamis along eastern Sicily (Italy): an overview

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