Papers by Alberto Armigliato
25° Convegno Nazionale GNGTS 2006, 2006
General Assembly 2019 of the European Geosciences Union (EGU), Apr 1, 2019
Frontiers in Earth Science, 2021
Tsunamis are unpredictable and infrequent but potentially large impact natural disasters. To prep... more Tsunamis are unpredictable and infrequent but potentially large impact natural disasters. To prepare, mitigate and prevent losses from tsunamis, probabilistic hazard and risk analysis methods have been developed and have proved useful. However, large gaps and uncertainties still exist and many steps in the assessment methods lack information, theoretical foundation, or commonly accepted methods. Moreover, applied methods have very different levels of maturity, from already advanced probabilistic tsunami hazard analysis for earthquake sources, to less mature probabilistic risk analysis. In this review we give an overview of the current state of probabilistic tsunami hazard and risk analysis. Identifying research gaps, we offer suggestions for future research directions. An extensive literature list allows for branching into diverse aspects of this scientific approach.
Natural Hazards and Earth System Sciences Discussions, 2013
Central America has been struck by at least 49 tsunamis between 1539 and 1996. As many as 37 of t... more Central America has been struck by at least 49 tsunamis between 1539 and 1996. As many as 37 of these events occurred at the Pacific Coast, and 31 were generated by earthquakes. Some of the events have been destructive, but despite this, tsunamis are an underrated hazard in Central America: people are not aware that they are at risk and even recent tsunami events have been forgotten. Recent studies, following the destructive tsunami occurred in Nicaragua in 1992, have revealed that Central America is a moderately tsunamigenic zone that is mainly affected by tsunamis triggered by earthquakes, especially at the Pacific coast where the Middle American Trench runs parallel to the coast. In this study, a statistical first and then a deterministic analysis for the Pacific coast of Central America has been carried out. The statistical approach aims to estimate the Gutenberg-Richter coefficients of the main seismic tsunamigenic regions of the area in order to assess the annual rate of occurrence of tsunamigenic earthquakes and their corresponding return period. A deterministic approach is then used to compute the tsunami run-up distribution along the coast corresponding to a given annual rate of occurrence of tsunamigenic earthquakes. 1 Introduction Central America is located at the southernmost isthmian portion of the North American continent, its main land lays on the North American Plate and on the Caribbean Plate whereas its Pacific coast runs parallel to the Middle American Trench, where the Cocos Plate subducts beneath the Caribbean Plate and the Nazca Plate subducts beneath the South American Plate. The region covers an area of approximately 524 000 km 2 and its population is about 40.5 million people. Earthquakes, landslides, mudslides and hurricanes are among the most known natural hazards. Tsunamis, on the other hand, are not considered a major hazard in Central America, people are not aware that they could be at risk and even recent tsunami 2984
SCHEMA, …, 2011
... According to documents provided by the Intergovernmental Coordination Group for the Indian Oc... more ... According to documents provided by the Intergovernmental Coordination Group for the Indian Ocean Tsunami Warning and Mitigation System (ICG/IOTWS, 2007), a tsunami hazard scenario is built up by specifying the various characteristics of a tsunamigenic source. ...
The automated detection of tsunamigenic signals at oceanic observation stations is highly desirab... more The automated detection of tsunamigenic signals at oceanic observation stations is highly desirable for the advancement of current tsunami early warning systems. These are supported with matching methods using large numbers of tsunami wave propagation modeling scenarios. New techniques using real-time scanning of hydrodynamic signals around a network of stations in an open ocean have been developed for the detection of tsunamis. Spectral ratios with respect to background signals and their levels of similarity across stations were investigated. The new developed algorithms will be wrapped as a reporting web service for the TRIDEC tsunami early warning system in the future.
Natural Hazards and Earth System Sciences Discussions, 2019
The 1783 Scilla tsunami, induced by a coastal landslide occurring during an intense seismic seque... more The 1783 Scilla tsunami, induced by a coastal landslide occurring during an intense seismic sequence in Calabria (South Italy), was one of the most lethal ever observed in Italy. It caused more than 1500 fatalities, most of which on the beach close to the town where people gathered to escape earthquake shaking. In this paper, complementing a previous work (Zaniboni et al., 2016) focusing on the very local tsunami effects in the town of Scilla, we study the tsunami impact on the Calabria and Sicily coasts out of Scilla. To this purpose we take into account the same landslide geometry considered in the previous study and perform three tsunami simulations, one embracing a larger region with a 50-m computational grid, and two covering the specific area of Capo Peloro, in Sicily, facing Scilla on the western side of the Messina Straits, with even higher resolution (10 m mesh). Numerical results show a very good agreement with the historical observations in Capo Peloro. Moreover, the resulting global tsunami inundation pattern provides a useful hint for tsunami hazard assessment in the Messina Straits area, which is known to be one of the most exposed to tsunami threat in Italy and in the Mediterranean Sea.
ABSTRACT The five-year project called RITMARE (“La Ricerca ITaliana per il MARE”) is a very ambit... more ABSTRACT The five-year project called RITMARE (“La Ricerca ITaliana per il MARE”) is a very ambitious national research and innovation program focussed on all aspects relevant to marine and coastal research, technology and management, with emphasis on networking and international cooperation. The program objectives fit into the overall European Commission vision documents and strategic programs and cover five major themes, one of which deals with technologies for the sustainable management of the coastal areas. The theme is further articulated in work-packages and specific actions, including the systematic and quantitative tsunami hazard assessment for the whole Italian coastlines. The University of Bologna takes part in the project RITMARE, being a member of the University Consortium Conisma, that is a direct partner in the project. We present here some preliminary results obtained by the Tsunami Research Team of the University of Bologna (TRT-UNIBO) by applying a modified version of a hybrid statistical-deterministic approach to the southern Tyrrhenian, Ionian and Adriatic coasts. A widely adopted approach formulates the problem of the tsunami hazard assessment in terms of the probability of occurrence of tsunamigenic earthquakes, which is appropriate in basins where the number of known historical tsunamis is too scarce to be used in reliable statistical analyses, and where the largest part of tsunamis have tectonic origin. The TRT-UNIBO approach starts by building a single homogeneous earthquake catalogue covering the whole national territory, as well as the adjacent areas that are believed to have the potential to produce tsunamis with relevant far-field effects along the Italian coasts. A proper statistical analysis of the catalogue allows retrieving the earthquake occurrence rate at a regional scale as well as in a set of cells in which the studied geographical domain is divided into. The final result of the statistical analysis is the computation for each cell of the parameters of the truncated cumulative Gutenberg-Richter law. A second step consists in determining the tsunamigenic potential by using suitable relationships between the earthquake magnitude and the initial disturbance of the sea in each cell. For each magnitude and hence for each initial condition offshore, the tsunami height at the coast is computed through empirical amplification formulas. The output of this second step is given by the spatial distribution of the minimum magnitude needed to produce tsunami heights at the coast larger than a given threshold. The results coming from the two steps are finally combined to determine the number and distribution of tsunamigenic earthquakes expected to occur over a given time interval and to produce tsunami heights larger than a given threshold along any stretch of the Italian coastline. We will present maps relative to different tsunami height thresholds over a suitable time interval (f.i. 10,000 years) and discuss the consistency with the information retrievable from the Euro-Mediterranean tsunami catalogue of the TRANSFER Project.
ABSTRACT A project for the planning of a coastal defense system for the provinces of Catania and ... more ABSTRACT A project for the planning of a coastal defense system for the provinces of Catania and Siracusa, in Sicily, is in the stage of feasibility analysis at the Building and Construction Interdepartmental Center for Industrial Research (CIRI), of the University of Bologna, with the focus on protection against extreme waves, such as tsunamis and storm waves. The eastern coast of Sicily, encompassing the coasts of Catania and Siracusa, is one of the most hazardous areas in Italy and in the Mediterranean as regards tsunamis, and it is also affected by extreme sea storms. The main goal of the project is to study the feasibility of a local Tsunami Warning System addressing near and far sources of seismic and landslide origin and to plan a sea-monitoring system capable to detect anomalous conditions for a wide spectral range of waves covering tsunamis as well as storms. The first phase of the project is the hazard assessment for extreme events, which is preparatory to the second phase, i.e. the feasibility study of a sea level and sea currents monitoring system based on new technologies. The coastal hazard assessment includes the identification of possible tsunami sources and the estimation of the tsunami threats, which allows one to recognize the most exposed coastal areas to tsunamis events. The identification of tsunami sources is made from literature and catalogs, while the use of numerical simulations of tsunamis is needed for tsunami hazard assessment and to evaluate the coastal inundation. The tsunami simulations are also a key information for the planning of the monitoring network, since it allows to characterize the signal that should be detected. As regards storm waves, we propose to extend the temporal base for the estimation of the significant wave height and other relevant statistics with the use of geophysical data, since recent works from literature suggest that the actual statistics for eastern Sicily might be underestimated.
Scenarios represent a very useful technique for the definition and evaluation of tsunami hazard a... more Scenarios represent a very useful technique for the definition and evaluation of tsunami hazard and risk for any given region, and a basic step in the frame of tsunami mitigation and preparedness and of sustainable coastal zone development. With the exception of very few countries, like Japan and the United States, emergency plans in the rest of the world have never taken serious care of tsunamis until the occurrence of the giant Indian Ocean tsunami on December 26, 2004. That event dramatically brought the problem of tsunami hazard and risk assessment to the general attention and showed the urgent need for implementation of tsunami early warning systems (TEWSs). The problem is particularly urgent for the Mediterranean countries that are known to have been attacked by numerous tsunamis in the past, several of which had catastrophic size and impact. This paper is an attempt to develop some simple scenarios of earthquake-generated tsunamis in the Mediterranean. We identify four different seismogenic areas in the western, central and eastern sectors of the basin. For each of them, we take into account a seismic fault capable of generating an earthquake with magnitude equal or larger than the highest magnitude registered in that region in historical times. Then we simulate numerically the ensuing tsunamis, highlighting the basic features of the wave propagation and roughly identifying the coastal sectors that are expected to suffer the heaviest tsunami effects. One of the most important outcomes is that these scenario tsunamis attack the nearest coasts within at most 15 minutes, which poses serious constraints for designing appropriate TEWS for the Mediterranean.
... The sliding body has been hypothesized to detach from close to the shoreline (Figure 2). Theg... more ... The sliding body has been hypothesized to detach from close to the shoreline (Figure 2). Thegeometry of the body has been conceived starting from the description by ... De Martini PM, Pantosti D., Palyvos N., Lemeille F., McNeill L., Collier R., 2004, Slip rates of the Aigion ...
Natural Hazards, 2014
ABSTRACT The M w = 9.1 mega-thrust Sumatra–Andaman earthquake that occurred on December 26, 2004,... more ABSTRACT The M w = 9.1 mega-thrust Sumatra–Andaman earthquake that occurred on December 26, 2004, was followed by a devastating tsunami that killed hundreds of thousands of people and caused catastrophic effects on human settlements and environments along many coasts of the Indian Ocean, where even countries very far from the source were affected. One of these cases is represented by the Republic of Seychelles, where the tsunami reached the region about 7 h after the earthquake and produced relevant damages, despite the country was more than 4,500 km far from the seismic source. In the present work, we present and discuss a study of the 2004 Sumatra tsunami by means of numerical simulations with the attention focused on the effects observed at the Seychelles Archipelago, a region never previously investigated with this approach. The case is interesting since these islands lay on a very shallow oceanic platform with steep slopes so as the ocean depth changes from thousands to few tens of meters over short distances, with significant effects on the tsunami propagation features: the waves are strongly refracted by the oceanic platform and the tsunami signal is modified by the introduction of additional frequencies. The study is used also to validate the UBO-TSUFD numerical code on a real tsunami event in the far field, and the results are compared with the available observations, i.e., the sea level time series recorded at the Pointe La Rue station, Mahé Island, and run-up measurements and inundation lines surveyed few weeks after the tsunami at Praslin Island, where the tsunami hit during low tide. Synthetic results are found in good agreement with observations, even though some of the observations remain not fully solved. Moreover, simulations have been run in high-tide condition since the 2004 Sumatra tsunami hitting at high tide can be taken as the worst-case scenario for the Seychelles islands and used for tsunami hazard and risk assessments.
Catania is one of the most important towns in Sicily, and more generally in southern Italy, due t... more Catania is one of the most important towns in Sicily, and more generally in southern Italy, due to its long historical and cultural tradition and to active industrial, commercial and touristic activities. Catania is located along the coast of eastern Sicily, which is well known to be one of the coastal areas most exposed to earthquake and tsunami hazard and
Marine Geology, 2014
Slides along continental margins represent a considerable source of hazard, especially when occur... more Slides along continental margins represent a considerable source of hazard, especially when occurring in shallow water close to a densely populated coast. Among the known landslide-tsunamis affecting harbors or coastal infrastructures, the 1977 event that hit the harbor of Gioia Tauro (SE Tyrrhenian Sea, Italy) is one of the less studied. According to historical reports, 5 m waves hit the western dock, provoking relevant damages on port facilities. Post-event bathymetric surveys found a lack of mass of more than 5 million m 3 at the head of the Gioia Tauro canyon, that starts just outside the harbor. After having considered two possible sliding bodies, the respective landslide motion and generated tsunami are calculated here through numerical in-house developed numerical codes, in order to assess their effects on the coast and validate the hypothesis of a landslide source for the 1977 event. Tsunami features inside the harbor basin are characterized as well, evidencing the importance of assessing the consequence of such small-scale events, not involving large areas but posing a relevant threat for coastal communities and infrastructures.
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Papers by Alberto Armigliato