2,037 research outputs found

    A new version of the European tsunami catalogue: updating and revision

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    A new version of the European catalogue of tsunamis is presented here. It differs from the latest release of the catalogue that was produced in 1998 and is known as GITEC tsunami catalogue in some important aspects. In the first place, it is a database built on the Visual FoxPro 6.0 DBMS that can be used and maintained under the PC operating systems currently available. Conversely, the GITEC catalogue was compatible only with Windows 95 and older PC platforms. In the second place, it is enriched by new facilities and a new type of data, such as a database of pictures that can be accessed easily from the main screen of the catalogue. Thirdly, it has been updated by including the newly published references. Minute and painstaking search for new data has been undertaken to re-evaluate cases that were not included in the GITEC catalogue, though they were mentioned in previous catalogues; the exclusion was motivated by a lack of data. This last work has focused so far on Italian cases of the last two centuries. The result is that at least two events have been found which deserve inclusion in the new catalogue: one occurred in 1809 in the Gulf of La Spezia, and the other occurred in 1940 in the Gulf of Palermo. Two further events are presently under investigation

    A revision of the 1783?1784 Calabrian (southern Italy) tsunamis

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    International audienceSouthern Italy is one of the most tsunamigenic areas in the Mediterranean basin, having experienced during centuries a large number of tsunamis, some of which very destructive. In particular, the most exposed zone here is the Messina Straits separating the coasts of Calabria and Sicily that was the theatre of the strongest Italian events. In 1783?1785 Calabria was shaken by the most violent and persistent seismic crisis occurred in the last 2000 years. Five very strong earthquakes, followed by tsunamis, occurred in a short interval of time (February?March 1783), causing destruction and a lot of victims in a vast region embracing the whole southern Calabria and the Messina area, Sicily. In this study we re-examined these events by taking into account all available historical sources. In particular, we focussed on the 5 and 6 February 1783 tsunamis, that were the most destructive. As regards the 5 February event, we found that it was underestimated and erroneously considered a minor event. On the contrary, the analysis of the sources revealed that in some localities the tsunami effects were quite strong. The 6 February tsunami, the strongest one of the sequence, was due to a huge earthquake-induced rockfall and killed more than 1500 people in the Calabrian village of Scilla. For this event the inundated area and the runup values distribution were estimated. Further, the analysis of the historical sources allowed us to find three new tsunamis that passed previously unnoticed and that occurred during this seismic period. The first one occurred a few hours before the large earthquake of 5 February 1783. The second was generated by a rockfall on 24 March 1783. Finally, the third occurred on 9 January 1784, probably due to a submarine earthquake

    Simulation of tsunamis induced by volcanic activity in the Gulf of Naples (Italy)

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    International audienceThe paper explores the potential of tsunami generation by pyroclastic flows travelling down the flank of the volcano Vesuvius that is found south of Naples in Italy. The eruption history of Vesuvius shows that it is characterised by large explosive eruptions of plinian or subplinian type during which large volume of pyroclastic flows can be produced. The most remarkable examples of such eruptions occurred in 79 AD and in 1631 and were catastrophic. Presently Vesuvius is in a repose time that, according to volcanologists, could be interrupted by a large eruption, and consequently proper plans of preparedness and emergency management have been devised by civil authorities based on a scenario envisaging a large eruption. Recently, numerical models of magma ascent and of eruptive column formation and collapse have been published for the Vesuvius volcano, and propagation of pyroclastic flows down the slope of the volcanic edifice up to the close shoreline have been computed. These flows can reach the sea in the Gulf of Naples: the denser slow part will enter the waters, while the lighter and faster part of the flow can travel on the water surface exerting a pressure on it. This paper studies the tsunami produced by the pressure pulse associated with the transit of the low-density phase of the pyroclastic flow on the sea surface by means of numerical simulations. The study is divided into two parts. First the hydrodynamic characteristics of the Gulf of Naples as regards the propagation of long waves are analysed by studying the waves radiating from a source that is a static initial depression of the sea level localised within the gulf. Then the tsunami produced by a pressure pulse moving from the Vesuvius toward the open sea is simulated: the forcing pulse features are derived from the recent studies on Vesuvian pyroclastic flows in the literature. The tsunami resulting from the computations is a perturbation involving the whole Gulf of Naples, but it is negligible outside, and persists within the gulf long after the transit of the excitation pulse. The size of the tsunami is modest. The largest calculated oscillations are found along the innermost coasts of the gulf at Naples and at Castellammare. The main conclusion of the study is that the light component of the pyroclastic flows produced by future large eruptions of Vesuvius are not expected to set up catastrophic tsunamis

    Assessment of tsunami hazards for the Central American Pacific coast from southern Mexico to northern Peru

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    Abstract. Central America (CA), from Guatemala to Panama, has been struck by at least 52 tsunamis between 1539 and 2013, and in the extended region from Mexico to northern Peru (denoted as ECA, Extended Central America in this paper) the number of recorded tsunamis in the same time span is more than 100, most of which were triggered by earthquakes located in the Middle American Trench that runs parallel to the Pacific coast. The most severe event in the catalogue is the tsunami that occurred on 2 September 1992 off Nicaragua, with run-up measured in the range of 5–10 m in several places along the Nicaraguan coast. The aim of this paper is to assess the tsunami hazard on the Pacific coast of this extended region, and to this purpose a hybrid probabilistic-deterministic analysis is performed, that is adequate for tsunamis generated by earthquakes. More specifically, the probabilistic approach is used to compute the Gutenberg–Richter coefficients of the main seismic tsunamigenic zones of the area and to estimate the annual rate of occurrence of tsunamigenic earthquakes and their corresponding return period. The output of the probabilistic part of the method is taken as input by the deterministic part, which is applied to calculate the tsunami run-up distribution along the coast

    Rupture process of the 2007 Niigata-ken Chuetsu-oki earthquake by non-linear joint inversion of strong motion and GPS data

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    We image the rupture history of the 2007 Niigata-ken Chuestu-oki (Japan) earthquake by a nonlinear joint inversion of strong motion and GPS data, retrieving peak slip velocity, rupture time, rise time and slip direction. The inferred rupture model contains two asperities; a small patch near the nucleation and a larger one located 10Ă·15 km to the south-west. The maximum slip ranges between 2.0 and 2.5 m and the total seismic moment is 1.6Ă—1019 Nm. The inferred rupture history is characterized by rupture acceleration and directivity effects, which are stable features of the inverted models. These features as well as the source-to-receiver geometry are discussed to interpret the high peak ground motions observed (PGA is 1200 gals) at the Kashiwazaki-Kariwa nuclear power plant (KKNPP), situated on the hanging-wall of the causative fault. Despite the evident source effects, predicted PGV underestimates the observed values at KKNPP by nearly a factor of 10

    Scenario-based assessment of buildings' damage and population exposure due to earthquake-induced tsunamis for the town of Alexandria, Egypt

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    Abstract. Alexandria is the second biggest city in Egypt with regards to population, is a key economic area in northern Africa and has very important tourist activity. Historical records indicate that it was severely affected by a number of tsunami events. In this work we assess the tsunami hazard by running numerical simulations of tsunami impact in Alexandria through the worst-case credible tsunami scenario analysis (WCTSA). We identify three main seismic sources: the western Hellenic Arc (WHA – reference event AD 365, Mw = 8.5), the eastern Hellenic Arc (EHA – reference event 1303, Mw = 8.0) and the Cyprus Arc (CA – hypothetical scenario earthquake with Mw = 8.0), inferred from the tectonic setting and from historical tsunami catalogues. All numerical simulations are carried out in two sea level conditions (mean sea level and maximum high-tide sea level) by means of the code UBO-TSUFD, developed and maintained by the Tsunami Research Team of the University of Bologna. Relevant tsunami metrics are computed for each scenario and then used to build aggregated fields such as the maximum flood depth and the maximum inundation area. We find that the case that produces the most relevant flooding in Alexandria is the EHA scenario, with wave heights up to 4 m. The aggregate fields are used for a building vulnerability assessment according to a methodology developed in the framework of the EU-FP6 project SCHEMA and further refined in this study, based on the adoption of a suitable building damage matrix and on water inundation depth. It is found that in the districts of El Dekhila and Al Amriyah, to the south-west of the port of Dekhila, over 12 000 (13 400 in the case of maximum high tide) buildings could be affected and hundreds of them could sustain damaging consequences, ranging from critical damage to total collapse. It is also found that in the same districts tsunami inundation covers an area of about 15 km2, resulting in more than 150 000 (165 000 in the case of maximum high tide) residents being exposed

    Visualisation of proteome-wide ordered protein abundances in Trypanosoma brucei

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    Background: Trypanosoma brucei is a protozoan parasite and etiological agent of human and animal African trypanosomiasis. It has a complex life cycle, but the most studied cellular types are the in vitro cultivated bloodstream- and procyclic-forms. These correspond to the replicating, mammalian host bloodstream-dwelling, slender trypomastigotes and tsetse vector midgut-dwelling procyclic lifecycle stages, respectively. Several proteomics studies have reported the differential abundance of proteins between these in vitro cultivated cell types. However, there are no datasets providing protein abundance, from most to least abundant, within and between both cell types. Methods: We used MaxQuant software 1.6.10.4 to reprocess a recent large-scale proteomics experiment from our laboratory and extracted intensity-based quantifications of the bloodstream and procyclic form proteomes. Results: We created a web interface to visually explore protein abundances within and between the in vitro cultivated T. brucei bloodstream and procyclic form proteomes. Conclusions: The protein abundance visualization tool, searchable by protein name(s) and attribute(s), is likely to be useful to the trypanosome research community. It will allow users to contextualise their proteins of interest in terms of their abundances in the T. brucei bloodstream and procyclic form proteomes

    Visualisation of experimentally determined and predicted protein N-glycosylation and predicted glycosylphosphatidylinositol anchor addition in Trypanosoma brucei.

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    Background: Trypanosoma brucei is a protozoan parasite and the etiological agent of human and animal African trypanosomiasis. The organism cycles between its mammalian host and tsetse vector. The host-dwelling bloodstream form of the parasite is covered with a monolayer of variant surface glycoprotein (VSG) that enables it to escape both the innate and adaptive immune systems. Within this coat reside lower-abundance surface glycoproteins that function as receptors and/or nutrient transporters. The glycosylation of the Trypanosoma brucei surface proteome is essential to evade the immune response and is mediated by three oligosaccharyltransferase genes; two of which, TbSTT3A and TbSTT3B, are expressed in the bloodstream form of the parasite. Methods: We processed a recent dataset of our laboratory to visualise putative glycosylation sites of the Trypanosoma brucei proteome. We provided a visualisation for the predictions of glycosylation carried by TbSTT3A and TbSTT3B, and we augmented the visualisation with predictions for Glycosylphosphatidylinositol anchoring sites, domains and topology of the Trypanosoma brucei proteome. Conclusions: We created a web service to explore the glycosylation sites of the Trypanosoma brucei oligosaccharyltransferases substrates, using data described in a recent publication of our laboratory. We also made a machine learning algorithm available as a web service, described in our recent publication, to distinguish between TbSTT3A and TbSTT3B substrates
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