The Mediterranean tsunami warning system is based on national monitoring centers (Tsunami Service Providers, TSPs) and operates under the IOC/UNESCO umbrella. For the first time we evaluate in depth the system’s performance for improving its operational effectiveness in conditions of extremely narrow time frames due to the near-field tsunami sources. At time 10 (± 2) min from the origin time, to, of the 2 May 2020 (Mw6.6) earthquake in Crete, the Greek, Italian and Turkish TSPs sent alerts to civil protection subscribers. A small tsunami (amplitude ~16 cm a.m.s.l.) of magnitude Mt6.8, arriving at south Crete in ~17 min from to, was documented from tide-gauge records and macroscopic observations. The analysis of the upstream alert messages showed that the tsunami alert efficiency is not adequate, since (1) earthquake parameters of low accuracy were used for the initial message, (2) alerts were issued after some forecasted wave arrival times had expired, (3) alert messages are characterized by various discrepancies and uncertainties. Our calculations showed that the upstream component improves if the alert time is shortened by a few minutes and the initial earthquake parameters are more accurate. Very late procedures were noted in the Greek civil protection downstream component, thus rendering response actions useless. In Israel, a bit more time was available to the authorities for decision making. A drastic improvement of the downstream component is needed to achieve timely alerting for local authorities and communities.
On 30 October 2020, an Mw = 7.0 earthquake struck the eastern Aegean Sea. It triggered earthquake environmental effects (EEEs) on Samos Island detected by field surveys, relevant questionnaires, and Interferometric Synthetic Aperture Radar (InSAR) analysis. The primary EEEs detected in the field comprise coseismic uplift imprinted on rocky coasts and port facilities around Samos and coseismic surface ruptures in northern Samos. The secondary EEEs were mainly observed in northern Samos and include slope failures, liquefaction, hydrological anomalies, and ground cracks. With the contribution of the InSAR, subsidence was detected and slope movements were also identified in inaccessible areas. Moreover, the type of the surface deformation detected by InSAR is qualitatively identical to field observations. As regards the EEE distribution, effects were generated in all fault blocks. By applying the Environmental Seismic Intensity (ESI-07) scale, the maximum intensities were observed in northern Samos. Based on the results from the applied methods, it is suggested that the northern and northwestern parts of Samos constitute an almost 30-km-long coseismic deformation zone characterized by extensive primary and secondary EEEs. The surface projection of the causative offshore northern Samos fault points to this zone, indicating a depth–surface connection and revealing a significant role in the rupture propagation.
Despite being relatively rare, Mediterranean tropical-like cyclones, also known as Medicanes, induce significant impacts on coastal Mediterranean areas. Under climate change, it is possible that these effects will increase in frequency and severity. Currently, there is only a broad understanding of the types and mechanisms of these impacts. This work studied Medicane Ianos (September 2020) and its effects on the Ionian Islands, in Greece, by developing a database of distinct impact elements based on field surveys and public records. Through this archive, the study explored the range of Ianos’ impacts to develop a systematic categorization. Results showed different types of effects induced on the natural and the built environment that can be grouped into 3 categories and 39 sub-categories in inland and coastal areas, indicating an extensive diversity of impacts, ranging from flooding and geomorphic effects to damages in various facilities, vehicles and infrastructure. The systematic description of the typology of Medicanes’ effects presented in this study is a contribution to a better understanding of their consequences as means to improve our ability to prepare for, respond to, and recover from them, a necessary stepping stone in improving the overall preparedness of both the general public and relevant authorities.
The study applies the Integrated Tsunami Intensity Scale (ITIS<sub>2012</sub>) 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 ITIS<sub>2012</sub> 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 ITIS<sub>2012</sub> criteria complementarity and is the tsunami intensity map of the study area.
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