Earthquake-triggered landslides along the Hyblean-Malta Escarpment (off Augusta, eastern Sicily, Italy) – assessment of the related tsunamigenic potential

Abstract. Eastern Sicily is affected by earthquakes and tsunamis of local and remote origin, which is known through numerous historical chronicles. Recent studies have put emphasis on the role of submarine landslides as the direct cause of the main local tsunamis, envisaging that earthquakes (in 1693 and 1908) did produce a tsunami, but also that they triggered mass failures that were able to generate an even larger tsunami. The debate is still open, and though no general consensus has been found among scientists so far, this research had the merit to attract attention on possible generation of tsunamis by landslides off Sicily. In this paper we investigate the tsunami potential of mass failures along one sector of the Hyblean-Malta Escarpment (HME). facing Augusta. The HME is the main offshore geological structure of the region running almost parallel to the coast, off eastern Sicily. Here, bottom morphology and slope steepness favour soil failures. In our work we study slope stability under seismic load along a number of HME transects by using the Minimun Lithostatic Deviation (MLD) method, which is based on the limit-equilibrium theory. The main goal is to identify sectors of the HME that could be unstable under the effect of realistic earthquakes. We estimate the possible landslide volume and use it as input for numerical codes to simulate the landslide motion and the consequent tsunami. This is an important step for the assessment of the tsunami hazard in eastern Sicily and for local tsunami mitigation policies. It is also important in view of tsunami warning system since it can help to identify the minimum earthquake magnitude capable of triggering destructive tsunamis induced by landslides, and therefore to set up appropriate knowledge-based criteria to launch alert to the population

Landslide deposits

Eastern Sicily is affected by earthquakes and tsunamis of local and remote origin, which is known through numerous historical chronicles. Recent studies have put emphasis on the role of submarine landslides as the direct cause of the main local tsunamis, envisaging that earthquakes (in 1693 and 1908) did produce a tsunami, but also that they triggered mass failures that were able to generate an even larger tsunami. The debate is still open, and though no general consensus has been found among scientists so far, this research had the merit to attract attention on possible generation of tsunamis by landslides off Sicily. In this paper we investigate the tsunami potential of mass failures along one sector of the Hyblean-Malta Escarpment (HME). facing Augusta. The HME is the main offshore geological structure of the region running almost parallel to the coast, off eastern Sicily. Here, bottom morphology and slope steepness favour soil failures. In our work we study slope stability under seismic load along a number of HME transects by using the Minimun Lithostatic Deviation (MLD) method, which is based on the limit-equilibrium theory. The main goal is to identify sectors of the HME that could be unstable under the effect of realistic earthquakes. We estimate the possible landslide volume and use it as input for numerical codes to simulate the landslide motion and the consequent tsunami. This is an important step for the assessment of the tsunami hazard in eastern Sicily and for local tsunami mitigation policies. It is also important in view of tsunami warning system since it can help to identify the minimum earthquake magnitude capable of triggering destructive tsunamis induced by landslides, and therefore to set up appropriate knowledge-based criteria to launch alert to the population

A GIS interface to the new Euro-Mediterranean Tsunami Catalogue produced by the TRANSFER project

TRANSFER, acronym standing for “Tsunami Risk ANd Strategies For the European Region”, is a three-year EU-funded research project that tackled all the main fields of interest in tsunami research, ranging from the improvement of the existing tsunami catalogue and the inventory of seismic and non-seismic tsunami sources, to the assessment of tsunami hazard, vulnerability and risk through innovative deterministic and statistical methodologies, with the final goal of identifying the best strategies for the reduction of tsunami risk. One of the largest efforts produced by the TRANFER consortium has been to convey all the results obtained during the project life into a unique and standardised GIS platform. We present here in some detail the GIS implementation of the improved version of the Euro-Mediterranean Tsunami Catalogue, which is the result of a careful revision, re-analysis, correction and integration of the results produced in the nineties by the EU funded GITEC and GITEC-TWO projects. All the TRANSFER partners involved in this work made some relevant improvements of the quality of the database, in terms of inclusion of new events or updating (or even exclusion) of existing events. The major improvements introduced in the TRANSFER tsunami catalogue with respect to the previous ones are: 1) the enlargement of the geographical area containing historical events (now the catalogue integrates events belonging to the Levantine sea and to Iceland); 2) the inclusion of the tide-gauge data relative to specific historical events; 3) for few events, the position of the places for which tsunami run-up and inundation data are available; 4) the introduction of the 12- points tsunami intensity scale by Papadopoulos and Imamura (2001). The GIS environment and the power of the underlying Relational Database Management Systems (RDBMS) allows to query the database in several respects. The most obvious starts from the geographical map containing the position of the historical events plotted with symbol size and colours depending on their intensities. Two main ArcGIS tools are then used to access the other information on the event. The "Identify" tool opens up a mask from which the user can retrieve all the details on date, time, source region and sub-region, reliability, cause, source parameters (intensity, magnitude and focal depth for earthquakes), position of the source. In the same mask, different layers give access to the list of places hit by that specific tsunami, containing the position of the site and the maximum reported run-up and inundation distance, when available. Moreover, it contains the list of references to studies dealing with that particular event. On the other hand, the "Hyperlink" tool opens up a text file containing the full description of the event and, when available, diagrams of measured sea-level data and photographs or similar material. The whole catalogue can be accessed and queried also in table format, allowing the user to perform his/her specific searches

The AD 365 Crete Earthquake/Tsunami Submarine Impact on the Mediterranean Region

The Calabrian and Hellenic subduction systems accommodate the African Eurasian plate convergence in the Mediterranean Sea and are the site of large earthquakes in the forearc region facing the northern African coasts. Some of the historical earthquakes were associated with the generation of tsunami waves affecting the entire Mediterranean basin. We investigated the submarine effects of the AD 365 Crete earthquake on the sedimentary records through the integrated analysis of geophysical data, turbidite deposits, and tsunami modelling. Seismic reflection images show that some turbidite beds are thick and marked by acoustic transparent layers at their top. Radiometric dating of the most recent of such mega-beds, the Homogenite/Augias turbidite (HAT), provide evidence for synchronous basin-wide sedimentation during a catastrophic event which has occurred in the time window of AD 364–415, consistent with the AD 365 Mw = 8.3–8.5 Crete earthquake/tsunamis. The HAT (up to 25 m thick) contains components from different sources, implying remobilization of material from areas very far from the epicentre. Utilizing the expanded stratigraphy of the HAT and the heterogeneity of the sediment sources of the Mediterranean margins, we reconstructed the relative contribution of the Italian, Maltan and African margins to the turbidite deposition. Our sedimentological reconstructions combined with tsunami modelling suggest that the tsunami following the Crete earthquake produced giant turbidity currents along a front over 2000 km long, from northern Africa to Italy. Our cores suggests that during the last 15,000 years, only two similar turbidites have been deposited in the deep basins, pointing to a large recurrence time of such extreme sedimentary events

Manuale per Scenari di Pericolosità e di Danno in Caso di Tsunami

Il manuale sugli scenari di maremoto è il risultato del lavoro svolto nell’ambito del progetto SCHEMA (finanziato dall’Unione Europea, in un periodo di 39 mesi dal 2007 al 2010) da un Consorzio di 11 partner, guidato da Geosciences Consultants. Il manuale è uno dei prodotti del progetto ed ha lo scopo di illustrare i concetti ed i metodi di base che sono stati elaborati ed applicati nel corso del progetto per produrre scenari utili per la stima della pericolosità e del danno derivante dall’impatto dei maremoti. Viene proposto un metodo generale che può essere facilmente adattato alle diverse necessità degli utilizzatori finali, che sono principalmente le pubbliche amministrazioni responsabili della pianificazione dello sviluppo delle zone costiere e dell’elaborazione delle strategie di protezione dai rischi naturali, così come le persone e le organizzazioni coinvolte nella gestione dei disastri e in politiche di mitigazione. La metodologia adottata nel progetto SCHEMA è stata applicata a cinque aree campione (Rabat, Marocco; Setúbal, Portogallo; Mandelieu, Francia; Catania, Italia; Balchik, Bulgaria) molto diverse l’una dall’altra, a riprova che essa è adattabile a una grande varietà di casi. Essa è stata testata con il coinvolgimento attivo degli utilizzatori finali, il che assicura che si tratta di uno strumento utile, pratico e sufficientemente flessibile da coprire le necessità delle singole località. Nella prima parte del manuale si definiscono i concetti di “Scenario di pericolosità” e di “Scenario di danno” in caso di maremoto, così come il concetto di “Peggior scenario credibile”. Quest’ultimo rappresenta il punto chiave del manuale, poiché il consorzio di SCHEMA ha scelto di adottare l’approccio del peggior scenario credibile piuttosto che quello basato su scenari risultanti da analisi probabilistiche. Il motivo della scelta è che si ritiene che non ci siano né conoscenze né dati a sufficienza per stimare la probabilità di tempi di ritorno dei maremoti, e quindi per ricavare i corrispondenti scenari. Il metodo è brevemente illustrato nel capitolo 3, nel quale si spiega che è costituito da tre fasi principali, ognuna delle quali suddivisibile in ulteriori sotto-fasi: 1) l’elaborazione di un certo numero di scenari di pericolosità per ogni area campione, che poi vengono combinati in un singolo scenario aggregato; 2) analisi di vulnerabilità degli elementi esposti al maremoto basata su osservazioni (derivanti da campagne di misura e da interpretazione di immagini satellitari); 3) sviluppo dello scenario di danno da maremoto. La fase 1 è descritta in moto dettagliato nel capitolo 4, mentre le fasi 2 e 3 sono illustrate nel successivo capitolo 5. Il manuale ha lo scopo di evidenziare i punti fondamentali della metodologia adottata nel progetto SCHEMA per gli scenari di maremoto, ed è perciò volutamente sintetico. Ogni dettaglio sui metodi e sulle loro applicazioni può essere trovato nei molti e dettagliati documenti (deliverables) prodotti dal consorzio durante tutto il progetto. Qui vengono illustrati solo i concetti fondamentali attraverso un numero di esempi presi dal lavoro svolto dai partner del consorzio. Il capitolo finale del manuale guarda al futuro, con enfasi sulle prossime sfide e su come la metodologia possa essere migliorata per affrontarle. In questo contesto l’argomento principale è la multi-pericolosità o, in altre parole, come gli scenari possano essere costruiti per considerare non solo i maremoti ma anche altri fenomeni pericolosi. La sfida rimane aperta nel senso che è ormai diffusa la consapevolezza i) che questo sia un serio problema e ii) che, allo stesso tempo, non ci siano metodi generali per affrontarlo.JRC.DG.G.7-Traceability and vulnerability assessmen

Handbook on tsunami hazards and damage scenarios

The handbook is one of the products of the SCHEMA project (FP 6 Space priority) and has been conceived to illustrate the basic concepts and methods that have been elaborated and applied in the project to produce tsunami scenarios in view of providing tools to assess hazard and potential damage resulting from tsunamis. One of the main objectives was the elaboration of a general methodology that can be used in all possible cases and that can be adapted easily to the needs of the end users, i.e. chiefly the public administrators responsible for planning of the coastal zone development and protection strategies as well as people and organisations involved in disasters management and mitigation policies. It is for these reasons, that the SCHEMA methodology has been applied to five test sites (Rabat, Morocco; Setúbal, Portugal; Mandelieu, France; Catania, Italy; Balchik, Bulgaria) that differ very much from one another, so proving that it is suitable for a quite large variety of cases, and that it has been tested with the active involvement of the end users, so ensuring that it will provide practical and useful tools and it is flexible enough to cover local needs.JRC.DG.G.7-Traceability and vulnerability assessmen

Manual de Cenários de Risco e Danos de Tsunami

O manual de cenários de tsunami é o resultado de um trabalho intenso realizado no âmbito do projecto europeu FP6 SCHEMA, co-financiado num período de 39 meses, de 2007 a 2010, num consórcio de 11 parceiros liderado pela Geosciences Consultants (Paris). O manual é um dos produtos do projecto, concebido para ilustrar os conceitos básicos e métodos criados e aplicados no projecto para a produção de cenários de tsunami, tendo em vista a disponibilização de ferramentas de avaliação de riscos de tsunami e danos potenciais. Um dos objectivos principais foi a elaboração de uma metodologia geral que pudesse ser facilmente adaptada às necessidades dos utilizadores finais, principalmente dos gestores públicos responsáveis pelo planeamento de estratégias de desenvolvimento e protecção costeiras, bem como das pessoas e organizações envolvidas na gestão de desastres e políticas de mitigação. Por estas razões, a metodologia do SCHEMA foi aplicada em cinco locais (Rabat, Marrocos; Setúbal, Portugal; Mandelieu, França; Catania, Itália; Balchik, Bulgária) com diferenças significativas entre si, tendo sido testada com o envolvimento activo dos utilizadores finais, assegurando a disponibilização de ferramentas úteis e práticas com flexibilidade suficiente para cobrir as necessidades locais. O manual define, em primeiro lugar, o significado de “cenário de risco de tsunami” e “cenário de danos devidos a tsunami”, bem como o conceito de “pior cenário credível”. Este último conceito é um ponto-chave do manual, uma vez que a escolha do consórcio SCHEMA consistiu na adopção da abordagem de pior cenário credível em detrimento de cenários elaborados por análise probabilística, por se crer não existirem conhecimentos e dados actuais suficientes para avaliar fielmente a probabilidade de retorno de tsunamis e consequentemente a criação de cenários probabilísticos correspondentes. A metodologia, descrita de forma sucinta no capítulo 3, consiste em três fases principais, por sua vez abrangendo outras sub-fases ou passos: 1 – Elaboração de um conjunto de cenários de risco de tsunami para cada local em estudo (também referido como zona-alvo), agregando-se num único cenário combinado; 2 – Análise da vulnerabilidade de elementos expostos, baseada em observações recolhidas em pesquisas de campo e na interpretação de imagens de satélite; 3 – Desenvolvimento de cenários de danos devidos a tsunami. A fase 1 é descrita em detalhe no capítulo 4, ao passo que as fases 2 e 3 são ilustradas no capítulo 5. Este manual tem como propósito realçar a abordagem SCHEMA aos cenários de tsunami e é deliberadamente pequeno e sintético. Todos os detalhes dos métodos e da sua aplicação podem ser obtidos nos vários e extensos documentos produzidos pelo consórcio no período de duração do projecto. Neste documento são apenas referidos os conceitos principais, ilustrados por exemplos recolhidos a partir do trabalho realizado pelos parceiros do consórcio. O capítulo final do manual aponta para o futuro, principalmente através do foco nos desafios futuros e a forma como a metodologia poderá ser melhorada para lidar com esses desafios. Neste contexto, o tema principal é o multi-risco ou, noutras palavras, a forma como os cenários podem ser criados para cobrir não apenas tsunamis mas também outros fenómenos de risco. O desafio está lançado, existindo actualmente o reconhecimento de que esta problemática é séria e antiga e que não há ainda certezas sobre a forma geral de lidar com o problema. Esperamos que sejam concretizados desenvolvimentos importantes nos próximos anos.JRC.DG.G.7-Traceability and vulnerability assessmen

Antihypertensive Treatment in the Elderly and Very Elderly: Always “the Lower, the Better?”

Arterial hypertension (HT) is age dependent and, with the prolongation of life expectancy, affects more and more elderly people. In the elderly, HT is a risk factor for organ damage and cardiovascular (CV) events. Both pharmacologic and nonpharmacologic reduction of blood pressure (BP) is associated with a corresponding decrease in systolic-diastolic or isolated systolic HT. Clinical trials have shown that BP lowering is associated with a decrease in stroke and other CV events. Therefore, BP reduction per se appears more important than a particular class of antihypertensive drugs. The benefit of antihypertensive treatment has been confirmed up to the age of 80 years, remaining unclear in the octogenarians. The benefit in lowering diastolic BP between 80 and 90 mmHg is well established, while that of lowering systolic BP below 140 mmHg requires further confirmations

Towards the new thematic Core service Tsunami within the EPOS research infrastructure

Tsunamis constitute a significant hazard for European coastal populations, and the impact of tsunami events worldwide can extend well beyond the coastal regions directly affected. Understanding the complex mechanisms of tsunami generation, propagation, and inundation, as well as managing the tsunami risk, requires multidisciplinary research and infrastructures that cross national boundaries. Recent decades have seen both great advances in tsunami science and consolidation of the European tsunami research community. A recurring theme has been the need for a sustainable platform for coordinated tsunami community activities and a hub for tsunami services. Following about three years of preparation, in July 2021, the European tsunami community attained the status of Candidate Thematic Core Service (cTCS) within the European Plate Observing System (EPOS) Research Infrastructure. Within a transition period of three years, the Tsunami candidate TCS is anticipated to develop into a fully operational EPOS TCS. We here outline the path taken to reach this point, and the envisaged form of the future EPOS TCS Tsunami. Our cTCS is planned to be organised within four thematic pillars: (1) Support to Tsunami Service Providers, (2) Tsunami Data, (3) Numerical Models, and (4) Hazard and Risk Products. We outline how identified needs in tsunami science and tsunami risk mitigation will be addressed within this structure and how participation within EPOS will become an integration point for community developmen