Italian Tsunami Effects Database (ITED): The First Database of Tsunami Effects Observed Along the Italian Coasts

Traditional tsunami catalogues are conceived as a collection of tsunamis classified by the generating cause, providing a general description of the effects observed for each tsunami. Those catalogues, even if they provide fundamental information, are not suitable for producing an exhaustive picture of the geographical distribution of the tsunami effects. In this paper we introduce the new Italian Tsunami Effects Database (ITED), a collection of evidence documenting the effects along the Italian coasts from historical times to present. The database comes forth the Euro-Mediterranean Tsunami Catalogue (EMTC) and focusses on the effects of tsunamis observed along the Italian coasts providing descriptive and quantitative information for each OP. The information reported in ITED does not only concern the effects produced by Italian tsunamis, but also those effects produced by tsunamis originated outside the Italian territory. ITED contains 318 OPs, related to 73 Italian tsunamis and to four tsunamis which occurred outside Italy. The database can be accessed through a WebApp that displays for each OP the description of effects, quantitative data (run-up, inundation, withdrawal, etc.) and tsunami intensity with the corresponding bibliographic references. The database also provides the tsunami intensity distribution along time (tsunami-history) for each site, allowing the end user to know how a place has been affected by tsunamis over the time. The information contained in ITED makes this database a useful tool to understand how tsunamis have affected the Italian territory and emphasizes the importance of studying the tsunami hazard along the Italian coasts.

The October 30, 2020 tsunami in the eastern Aegean Sea: Intensity mapping on Samos island based on the Integrated Tsunami Intensity Scale (ITIS 2012)

<p>On October 30, 2020, an Mw=7.0 earthquake occurred offshore northern Samos Island (Eastern Aegean, Greece). It was felt over a large area extending from Samos to Peloponnese in Greece and from Izmir to Istanbul in Turkey. It triggered many earthquake environmental effects and damage to buildings resulting in 119 fatalities in both countries. Among the triggered phenomena, tsunami waves with maximum height ~3.35 m struck mainly the northern coastal part of Samos Island and then other islands in the Aegean Sea including Chios, Andros, Ikaria Islands, and the western coast of Turkey.</p><p>In order to assess the tsunami intensity in Samos Island, the Integrated Tsunami Intensity Scale (ITIS 2012) was applied. ITIS 2012 is a recently introduced 12-grade scale ranging from I (not felt) to XII (completely devastating) and it is based on the assessment of a large number of objective criteria, grouped in six categories (physical quantities, impact on humans, impact on mobile objects, impacts on infrastructure, environmental effects and impact on structures).</p><p>In this context, the above information and data were used for the October 30, 2020 tsunami in Samos. Observations and measurements during a field survey conducted in Samos shortly after the event by the authors were mainly used for assigning intensities. Moreover, other sources included eyewitness, photos and videos from locals capturing the type and the extent of the tsunami impact as well as reports on the qualitative and quantitative tsunami properties and impact on the natural and built coastal environment were also used. Based on the recorded data and information and the guidelines for applying ITIS 2012, tsunami quantities and impact on humans, mobile objects, coastal infrastructure, the natural environment and buildings were taken into account. All available data were added and edited in a database in Geographic Information Systems (GIS) environment, specially designed for the purpose of the study. Then, the respective tsunami intensities were assigned in the studied sites. Moreover, interpolation methods have been also used in order to obtain zones of different intensity in the inundated coastal areas. The results included an ITIS 2012 intensity map of Samos Island.</p><p>Based on the assigned intensities, the October 30, 2020 tsunami is characterized as a moderate to strong event with considerable impact on all ITIS 2012 categories. The spatial distribution and the amount of the tsunami effects along the coastal area of Samos enabled the compilation of an intensity map with high resolution indicating that this scale works well for modern events with large amounts of effects and related information. Moreover, the individual criteria of the ITIS 2012 successfully complemented each other resulting in a detailed, concise and precise intensity map.</p><p>This is the first time that the ITIS 2012 is applied for a modern tsunami with large amounts of effects in the Mediterranean Region and especially the Aegean Sea. The results could be used for a more effective disaster risk management and risk mitigation strategies for tsunami in the Mediterranean Sea.</p>

Italian Tsunami Effects Database (ITED): the first database of tsunami effects observed along the Italian coasts

The Italian Tsunami Effects Database (ITED), consists of an ensemble of records reporting tsunami effects observed at several Observation Points (OP) along the Italian coasts from historical times. ITED was compiled starting from the Euro Mediterranean Tsunami Catalogue (EMTC) and it focuses on the propagation effects observed along the Italian coasts, providing information on how each locality was interested by tsunami effects over time. The effects reported in ITED are related to tsunamis occurred within the Italian territory and contained in the EMTC; these events were excerpt, analyzed and updated according to recent studies published in literature. The database can be accessed through a web GIS application, that displays the location of the OPs indicating for each of them the description of tsunami effects found in literature and the corresponding bibliographic references as well as the metrics related to the observed event. Based on those descriptions, the estimate value of the tsunami intensity has been assigned to each OP, according to both the Sieberg-Ambraseys and the Papadopoulos-Imamura scales. All the ITED data, including quantitative data such as runup, inundation, withdrawal, can be retrieved by accessing online the database through the WebApp that was expressly designed and built for this purpose. ITED contains 300 observations of tsunami effects at 225 OPs referred to 186 Italian main localities, hereafter called Place Name (PN) related to 72 Italian tsunamis. The database provides also the tsunami-history for each PN, allowing the end user to have a complete picture of how the PN is prone to tsunami effects.The realization of ITED was also the occasion to update Italian tsunamis contained in the EMTC, leading to the release of a new version of the EMTC catalogue, named EMTC2.0. ITED was specifically built to meet the needs of the tsunami hazard community, thus providing useful information that can improve the knowledge on how much the national territory is exposed to tsunami risk.

Tsunami intensity mapping: applying the integrated Tsunami Intensity Scale (ITIS2012) on Ishinomaki Bay Coast after the mega-tsunami of Tohoku, March 11, 2011

The study applies the Integrated Tsunami Intensity Scale (ITIS₂₀₁₂) criteria to map the tsunami intensities distribution in the broader Ishinomaki area, for the 9 Mw March 11, 2011 event offshore Tohoku, Japan. Based on reports, satellite imagery and published information, impact data was mapped, intensity values were assigned and thematic impact maps (layers) were created for each of the ITIS₂₀₁₂ six criteria categories. Most of the criteria result in a mosaic of intensities, which is in many cases due to lack of data, depending on the land use. Two methodologies were used to produce the final map. A land-use-based weighted overlay was applied integrating the six layers, resulting in a final map that rather shows damage tsunami assessment on Ishinomaki area. The second final map was produced using the maximum intensity grade throughout the six layers for each pixel. This map showed an excellent zoning filling in any gaps due to information lack in some layers and areas, with maximum intensity data from the others, highlighting the ITIS₂₀₁₂ criteria complementarity and is the tsunami intensity map of the study area.