Calibration of a real-time tsunami detection algorithm for sites with no instrumental tsunami records: application to coastal tide-gauge stations in eastern Sicily, Italy

Abstract. Coastal tide gauges play a very important role in a tsunami warning system, since sea-level data are needed for a correct evaluation of the tsunami threat, and the tsunami arrival has to be recognized as early as possible. Real-time tsunami detection algorithms serve this purpose. For an efficient detection, they have to be calibrated and adapted to the specific local characteristics of the site where they are installed, which is easily done when the station has recorded a sufficiently large number of tsunamis. In this case the recorded database can be used to select the best set of parameters enhancing the discrimination power of the algorithm and minimizing the detection time. This chance is however rare, since most of the coastal tide-gauge stations, either historical or of new installation, have recorded only a few tsunamis in their lifetimes, if any. In this case calibration must be carried out by using synthetic tsunami signals, which poses the problem of how to generate them and how to use them. This paper investigates this issue and proposes a calibration approach by using as an example a specific case, which is the calibration of a real-time detection algorithm called TEDA (Tsunami Early Detection Algorithm) for two stations (namely Tremestieri and Catania) in eastern Sicily, Italy, which were recently installed in the frame of the Italian project TSUNET, aiming at improving the tsunami monitoring capacity in a region that is one of the most hazardous tsunami areas of Italy and of the Mediterranean

Tsunami generation in Stromboli island and impact on the south-east Tyrrhenian coasts

Stromboli is one of the most active volcanoes in the Aeolian island arc in south Tyrrhenian sea, Italy. In the last 100 years the most relevant volcanic eruptions have beenaccompanied by local tsunamis, that have caused damage and casualties. In some cases the direct mechanism of local tsunami generation is clear, i.e. pyroclastic flows entering the sea. In some others it is uncertain and some speculation concerning the collapse of the eruptive column on the sea surface or the failure of some underwater mass can be made. But the ordinary activity is unlikely to generate large regional tsunamis. These can be produced by the lateral collapse of the volcanic cone that geomorphological and volcanological&nbsp; investigations have proven to have occurred repeatedly in the recent history of the volcano, with return period in the order of some thousands of years. The last episode is dated to less than 5 ka BP, and left the Sciara del Fuoco scar on the north-west flank of Stromboli.</p> <p style='line-height: 20px;'>Based on previous studies, the possible collapse of the nortwestern sector of Stromboli and the consequent generation and propagation of a tsunami are explored. The impact on Stromboli and on the other islands of the Aeolian archipelago is estimated, as well as the impact on the coast of Sicily and the Tyrrhenian coasts of Calabria. The simulation is carried out by means of a double model: a Lagrangian block model to compute the motion of the collapsing mass, and a finite-element hydrodynamic model to compute the evolution of the tsunami. Two distinct tsunami simulations are carried out, one on a very fine grid around the source region to evaluate the tsunami near Stromboli, and one utilising a coarser grid covering the whole south-east Tyrrhenian sea to compute the tsunami propagation toward Sicily and Calabria. It is found that a huge-volume collapse of the north-western flank of the Stromboli cone is capable of producing a regional tsunami which is catastrophic at the source and devastating on long stretches of Tyrrhenian coasts, but particularly in the neighbouring islands of Panarea and Salina, and along the Calabria coasts around Capo Vaticano

Development of a Pilot Borehole Storage System of Solar Thermal Energy: Modeling, Design, and Installation

Borehole thermal energy storage systems represent a potential solution to increase the energy efficiency of renewable energy plants, but they generally have to comply with strict regulatory frameworks, mainly due to the deliberate modification of the subsoil’s natural state. This paper presents the design, testing, and monitoring phases carried out to set up a borehole thermal energy storage (BTES) system able to exploit the excess solar heat from photovoltaic thermal (PVT) collectors. The case study is the refurbishment of a pig nursery barn, hosting up to 2500 weaners, in Northern Italy. This study aims to define a BTES suitable to develop a heating system based on renewable energy, ensuring environmental protection and long-term sustainability. The retrofitting intervention includes the installation of a dual-source heat pump (DSHP), in order to recover the solar heat stored in summer during winter. Specific constraints by the Environmental Authority were as follows: maximum storage temperature of 35 °C, authorization to intercept the shallowest aquifer at a maximum depth of 30 m, obligation of BHE grouting, and the definition of a strategy for continuous measuring and monitoring of the groundwater’s thermophysical properties. The results were used as inputs to optimize the design and installation of the integrated system with PVT, BTES, and DSHP

Local thermodynamical equilibrium and the beta frame for a quantum relativistic fluid

We discuss the concept of local thermodynamical equilibrium in relativistic hydrodynamics in flat spacetime in a quantum statistical framework without an underlying kinetic description, suitable for strongly interacting fluids. We show that the appropriate definition of local equilibrium naturally leads to the introduction of a relativistic hydrodynamical frame in which the four-velocity vector is the one of a relativistic thermometer at equilibrium with the fluid, parallel to the inverse temperature four-vector \beta, which then becomes a primary quantity. We show that this frame is the most appropriate for the expansion of stress-energy tensor from local thermodynamical equilibrium and that therein the local laws of thermodynamics take on their simplest form. We discuss the difference between the \beta frame and Landau frame and present an instance where they differ.Comment: 22 pages, 3 figures. To appear in Eur. Phys. J.

The Bag320 satellite DNA family in Bacillus stick insects (Phasmatodea): Different rates of molecular evolution of highly repetitive DNA in bisexual and parthenogenetic taxa

The Bag320 satellite DNA (satDNA) family was studied in seven populations of the stick insects Bacillus atticus (parthenogenetic, unisexual) and Bacillus grandii (bisexual). It was characterized as widespread in all zymoraces of B. atticus and in all subspecies of B. grandii. The copy number of this satellite is higher in the bisexual B. grandii (15%-20% of the genome) than in the parthenogenetic B. atticus (2%- 5% of the genome). The nucleotide sequences of 12 Bag320 clones from B. atticus and 17 from B. grandii differed at 13 characteristic positions by fixed nucleotide substitutions. Thus, nucleotide sequences from both species cluster conspecifically in phylogenetic dendrograms. The nucleotide sequences derived from B. grandii grandii could he clearly discriminated from those of B. grandii benazzii and B. grandii maretimi on the basis of 25 variable sites, although all taxa come from Sicily. In contrast, the Bag320 sequences from B. atticus could not he discriminated accordingly, although they derive from geographically quite distant populations of its three zymoraces (the Italian and Greek B. atticus atticus, the Greek and Turkish B. atticus carius, and the Cyprian B. atticus cyprius). The different rate of evolutionary turnover of the Bag320 satDNA in both species can he related to their different modes of reproduction. This indicates that meiosis and chromosome segregation affect processes in satDNA diversification

The role of working memory on writing processes.

Literature has extensively demonstrated the coordination role of working memory (WM) in complex tasks such as writing. However, previous studies mostly concentrated on the relation between passive WM (e.g., WM span) components and specific writing tasks (e.g., dictation). Here, we aimed to investigate the relationship between different writing skills and the performance on a WM updating task measuring the more active components of WM. From a pool of 160 Italian pupils (grades 3–5), we selected 46 children divided in two groups based on their WM updating performance. The first group consisted of 21 children with low WM updating performance (≤10th percentile), the second group consisted of 25 children with high WM updating performance (≥90th percentile). All children were tested on a battery of writing tasks to assess writing speed, orthographic skills, and competences in expressive writing. MANOVAs and a discriminant analysis were computed to assess group differences and the contribution of the different writing tests in correctly predicting group membership. The results revealed that children with high WM updating performance scored significantly higher than children with low WM updating performance on most of the writing tasks. These results highlight the relevant role of the active components of WM on writing processes. In addition, they suggest that the improvement of writing skills should rely not only on the training of the specific processes implied in this complex task, but also on the training of the cognitive processes that support them, such as active WM processes

Tsunami hazard for the city of Catania, eastern Sicily, Italy, assessed by means of Worst-case Credible Tsunami Scenario Analysis (WCTSA)

Eastern Sicily is one of the coastal areas most exposed to earthquakes and tsunamis in Italy. The city of Catania that developed between the eastern base of Etna volcano and the Ionian Sea is, together with the neighbour coastal belt, under the strong menace of tsunamis. This paper addresses the estimation of the tsunami hazard for the city of Catania by using the technique of the Worst-case Credible Tsunami Scenario Analysis (WCTSA) and is focused on a target area including the Catania harbour and the beach called La Plaia where many human activities develop and many important structures are present. The aim of the work is to provide a detailed tsunami hazard analysis, firstly by building scenarios that are proposed on the basis of tectonic considerations and of the largest historical events that hit the city in the past, and then by combining all the information deriving from single scenarios into a unique aggregated scenario that can be viewed as the &lt;i&gt;worst virtual scenario&lt;/i&gt;. Scenarios have been calculated by means of numerical simulations on computational grids of different resolutions, passing from 3 km on a regional scale to 40 m in the target area. La Plaia beach results to be the area most exposed to tsunami inundation, with inland penetration up to hundreds of meters. The harbour turns out to be more exposed to tsunami waves with low frequencies: in particular, it is found that the major contribution to the hazard in the harbour is due to a tsunami from a remote source, which propagates with much longer periods than tsunamis from local sources. This work has been performed in the framework of the EU-funded project SCHEMA

The application of a stockpile stochastic model into long-term open pit mine production scheduling to improve the feed grade for the processing plant

This paper presents a chance-constrained integer programming approach based on the linear method to solve the long-term open pit mine production scheduling problem. Specifically, a single stockpile has been addressed for storing excess low-grade material based on the availability of processing capacity and for possible future processing. The proposed scheduling model maximizes the project NPV while respecting a series of physical and economic constraints. Differently from common practice, where deterministic models are used to calculate the average grade for material in the stockpiles, in this work a stochastic approach was performed, starting from the time of planning before the stockpile realization. By performing a probability analysis on two case studies (on iron and gold deposits), it was proven that the stockpile attributes can be treated as normally distributed random variables. Afterwards, the stochastic programming model was formulated in an open pit gold mine in order to determine the optimum amount of ore dispatched from different bench levels in the open pit and at the same time a low-grade stockpile to the mill. The chance-constrained programming was finally applied to obtain the equivalent deterministic solution of the primary model. The obtained results have shown a better feed grade for the processing plant with a higher NPV and probability of grade blending constraint satisfaction, with respect to using the traditional stockpile deterministic model.