A new dataset and empirical relationships between magnitude/intensity and epicentral distance for liquefaction in central-eastern Sicily

Strong earthquakes can trigger several phenomena inducing soil deformation, such as liquefaction, ground fracturing and landslides, which can often cause more damage than the seismic shaking itself. A research performed on numerous historical accounts reporting descriptions of seismogeological effects in central-eastern Sicily, allowed the authors to update the previous liquefaction datasets. 75 liquefaction-induced phenomena observed in 26 sites, triggered by 14 earthquakes, have been used to define relationships between intensity/magnitude values and epicentral distance from the liquefied sites. The proposed upper bound-curves, at regional scale for central- eastern Sicily, are realized by using the updating liquefaction dataset and also the new CPTI04 Italian earthquake parametric catalogue. These relationships can be useful in hazard assessment to evaluate the minimum energy of an earthquake inducing liquefactions

Discrimination of tsunami sources (Earthquake vs. Landslide) on the basis of historical data in Eastern Sicily and southern Calabria

The source mechanisms responsible for large historical tsunamis that have struck eastern Sicily and southern Calabria are a topic of robust debate. We have compiled a database of historical coeval descriptions of three large tsunamis: 11 January 1693, 6 February 1783, and 28 December 1908. By using accounts of run-up and inundation and employing an approach proposed by Okal and Synolakis in 2004, we can provide discriminants to define the nature of the near-field tsunami sources (fault dislocation or landslide). Historical reports for the 1908 event describe affected localities, maximum runups, and inundation areas. However, for the 1693 and 1783 tsunamis, reports are limited to inundation and occasional run-up estimates. We calculate run-up values for these events using available relations between inundation and run-up. We employed the model of Okal and Synolakis to the obtained profiles of tsunami run-up along the inundated shorelines. The 1908 run-up data distribution confirms that the tsunami is compatible with a seismic dislocation source, whereas the 1783 data supports contemporary observations and recent offshore investigations suggesting that the tsunami was produced by an earthquake-triggered submarine landslide. Analysis of the 1693 event data suggests that the tsunami was generated during a tectonic event and thus a seismogenic source should be found offshore

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

Magnetothermodynamics: Measurements Of The Thermodynamic Properties In A Relaxed Magnetohydrodynamic Plasma

We have explored the thermodynamics of compressed magnetized plasmas in laboratory experiments and we call these studies ‘magnetothermodynamics’. The experiments are carried out in the Swarthmore Spheromak eXperiment device. In this device, a magnetized plasma source is located at one end and at the other end, a closed conducting can is installed. We generate parcels of magnetized plasma and observe their compression against the end wall of the conducting cylinder. The plasma parameters such as plasma density, temperature and magnetic field are measured during compression using HeNe laser interferometry, ion Doppler spectroscopy and a linear dot{B} probe array, respectively. To identify the instances of ion heating during compression, a PV diagram is constructed using measured density, temperature and a proxy for the volume of the magnetized plasma. Different equations of state are analysed to evaluate the adiabatic nature of the compressed plasma. A three-dimensional resistive magnetohydrodynamic code (NIMROD) is employed to simulate the twisted Taylor states and shows stagnation against the end wall of the closed conducting can. The simulation results are consistent to what we observe in our experiments

Composition of Ragusano Cheese During Aging

Ragusano cheese is a brine-salted pasta filata cheese. Composition changes during 12 mo of aging were determined. Historically, Ragusano cheese has been aged in caves at 14 to 16 degrees C with about 80 to 90% relative humidity. Cheeses (n = 132) included in our study of block-to-block variation were produced by 20 farmhouse cheese makers in the Hyblean plain region of the Province of Ragusa in Sicily. Mean initial cheese block weight was about 14 kg. The freshly formed blocks of cheese before brine salting contained about 45.35% moisture, 25.3% protein, and 25.4% fat, with a pH of 5.25. As result of the brining and aging process, a natural rind forms. After 12 mo of aging, the cheese contained about 33.6% moisture, 29.2% protein, 30.0% fat, and 4.4% salt with a pH of 5.54, but block-to-block variation was large. Both soluble nitrogen content and free fatty acid (FFA) content increased with age. The pH 4.6 acetate buffer and 12% TCA-soluble nitrogen as a percentage of total nitrogen were 16 and 10.7%, respectively, whereas the FFA content was about 643 mg/100 g of cheese at 180 d. Five blocks of cheese were selected at 180 d for a study of variation within block. Composition variation within block was large; the center had higher moisture and lower salt in moisture content than did the outside. Composition variation within blocks favored more proteolysis and softer texture in the center

Identification of tsunami deposits in south-eastern Sicily: evidence for the 365 A.D. Crete earthquake?

In the past decade, the methodologies and techniques of paleoseismological studies have evolved towards a multidisciplinary approach for the characterization of past earthquakes. Along with traditional geologic and geomorphologic near-fault investigations, off-fault studies of evidence for past earthquakes, such as soft sediment deformation (e.g. Moretti, 2000; Marco and Agnon, 2005), evidence of liquefaction (e.g. Tuttle et al., 2002; Guarnieri et al., 2009) and tsunami deposits (Dawson and Stewart, 2007; Pantosti et al., 2008; De Martini et al., 2009) are considered useful tools in the assessment of paleoearthquakes ages, magnitudes, and earthquake recurrence rates. We present the preliminary results of off-fault paleoseismological studies carried out in south-eastern Sicily, focused to identify evidence of tsunami inundations

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

Inspiratory muscle workload due to dynamic intrinsic PEEP in stable COPD patients: effects of two different settings of non-invasive pressure-support ventilation.

BACKGROUND: In severe stable hypercapnic COPD patients the amount of pressure time product (PTP) spent to counterbalance their dynamic intrinsic positive end expiratory pressure (PEEPi,dyn) is high: no data are available on the best setting of non invasive pressure support ventilation (NPSV) to reduce the inspiratory muscle workload due to PEEPi,dyn. METHODS: The objectives of this randomised controlled physiological study were: 1. To measure the inspiratory muscle workload due to PEEPi,dyn 2. To measure the effects on this parameter of two settings of NPSV in stable COPD patients with chronic hypercapnia admitted in a Pulmonary Division of two Rehabilitation Centers. Twenty-three stable COPD patients with chronic hypercapnia on domiciliary nocturnal NPSV for 30 +/- 20 months were submitted to an evaluation of breathing pattern, PEEPi,dyn, inspiratory muscle workload and its partitioning during both assisted and unassisted ventilation. Two settings of NPSV were randomly applied for 30 minutes each: i- "at patient's comfort" (C): Inspiratory pressure support (IPS) was the maximal tolerated pressure able to reduce awake PaCO2 with the addition of a pre-set level of external PEEP (PEEPe); ii- "physiological setting" (PH): the level of IPS able to achieve a > 40% and < 90% decrease in transdiaphragmatic pressure in comparison to spontaneous breathing (SB). A PEEPe level able to reduce PEEPi,dyn by at least 50% was added. RESULTS: During SB the tidal diaphragmatic pressure-time product (PTPdi/b) was 17.62 +/- 7.22 cmH2O*sec, the component due to PEEPi,dyn (PTPdiPEEPi,dyn) being 38 +/- 17% (range: 16-65%). Compared to SB,PTPdiPEEPi,dyn was reduced significantly with both settings, the reduction being greater with PH compared to C. CONCLUSIONS: In conclusion in severe COPD patients with chronic hypercapnia the inspiratory muscle workload due to PEEPidyn is high and is reduced by NPSV at a greater extent when ventilator setting is tailored to patient's mechanics