From earthquake monitoring to tsunami warning in the Mediterranean Sea

Figure 1 - Tsunami hazard map in the Mediterranean Sea and historical tsunamis (symbols as in the legend on the left). More than 85% of tsunamis in the Mediterranean were caused by strong earthquakes. The most exposed areas are those of Greece, Egypt and Libya, and southern Italy.

Figure 1 - Tsunami hazard map in the Mediterranean Sea and historical tsunamis (symbols as in the legend on the left). Over 85% of tsunamis in the Mediterranean were caused by strong earthquakes. The most exposed areas are those of Greece, Egypt and Libya, and southern Italy.

Figure 2 - Earthquake epicenters in the Mediterranean since 2017. The colored symbols indicate the seismic events that have caused the activation of the CAT, with various degrees of severity (left legend on the map). In 2021 there were two more events, one off Algeria and another in the Adriatic Sea (Croatia).

Figure 2 - Epicenters of Mediterranean earthquakes since 2017. The colored symbols indicate the seismic events that caused the activation of the CAT, with various degrees of severity (legend on the left of the map). In 2021 there were two more events, one off the coast of Algeria and another in the Adriatic Sea (Croatia).

Figure 3 - The last seismic event that produced a tsunami in the Mediterranean Sea during the period of operation of the CAT analyzed in this study (2017-2020). Epicenter at the island of Samos, magnitude 7.0, 30 October 2020. Note the red alert points and the orange alert points. The isolines in the map represent the isochrones of the tsunami (the lines of the traveled time). For this event, the CAT issued a tsunami warning eight minutes after the earthquake.

Figure 3 - The last seismic event that produced a tsunami in the Mediterranean Sea during the period of operation of the CAT analyzed in this study (2017-2020). Epicenter at the island of Samos, magnitude 7.0, 30 October 2020. Note the points on red alert and those on orange alert. The isolines on the map represent the tsunami isochrones (the time lines travelled). For this event, the CAT issued the tsunami warning eight minutes after the earthquake.

The functioning and results of earthquake and tsunami monitoring in the Mediterranean Sea in a study by the INGV CAT

Evaluating the functioning of the tsunami warning system in the Mediterranean area, reflecting on the critical issues that have emerged and identifying areas for improvement to be implemented, constitute the focus of the study "From seismic monitoring to tsunami warning in the Mediterranean Sea" just published in the journal 'Seismological Research Letters' on the activities of the first four years of the Tsunami Alert Center (CAT-INGV), conducted by the research group of the National Institute of Geophysics and Volcanology (INGV).

“The risk due to tsunamis is little known but also present in our seas. These are rare events but with enormous destructive potential. The purpose of this study is to analyze the procedures currently in use at the Tsunami Warning Center and identify the tools to improve the service by making it faster and more efficient”, explains Alessandro Amato, Head of CAT-INGV and first author of the study. “We have analyzed hundreds of earthquakes around the world and a few dozen in the CAT's area of ​​expertise, ie the Mediterranean Sea. Some of the strongest earthquakes that occurred between 2017 and 2020, when the CAT was in operation, generated small tsunamis. In a couple of cases, i.e. in 2017 and 2020 between Greece and Turkey, floods of up to two meters were observed; in the case of the recent magnitude 7 earthquake in Samos there was extensive damage and one death due to the tsunami. Tsunami warning messages continues Amato, “were sent by the CAT between 7 and 10 minutes after the occurrence of the earthquakes, a useful time to allow evacuation in almost all coastal areas potentially affected by the tsunami”.

The CAT is part of the national warning system for seismic tsunamis which was established in 2017 by the Presidency of the Council of Ministers; the latter has entrusted the national Civil Protection Department with the coordination of activities with INGV and the Higher Institute for Environmental Protection and Research (ISPRA). 

CAT-INGV is a Tsunami Service Provider of the NEAMTWS Intergovernmental Group (North-East Atlantic, Mediterranean and connected seas Tsunami Warning System) which acts under the coordination of UNESCO's IOC (Intergovernmental Oceanographic Commission). In the event of a potential tsunami, the CAT sends warning messages to the Italian DPC and to numerous UNESCO member states in the Euro-Mediterranean area.

"The monitoring of tsunamis of seismic origin", continues Amato, “is carried out starting from the real-time analysis of strong earthquakes. To this end, we use seismological techniques that allow the rapid calculation of the hypocentral coordinates and the magnitude of each earthquake that occurs at sea or on the coasts of the Mediterranean Sea".

"A systematic review”, concludes Alessandro Amato, “it has allowed us to identify some elements that will allow us to speed up the calculation procedures by reducing the alert times, while maintaining a good degree of accuracy of the estimates. Finally, the importance of bridging the last segment of the warning chain was emphasised, the one that must allow the warning messages to reach the citizen. An increase in awareness of tsunami risk and specific preparation of the population are necessary tools for risk reduction".

#ingv #cat #tsunami #Mediterranean

Link: https://pubs.geoscienceworld.org/ssa/srl/article-abstract/doi/10.1785/0220200437/595804/From-Seismic-Monitoring-to-Tsunami-Warning-in-the?redirectedFrom=fulltext

From Seismic Monitoring to Tsunami Warning in the Mediterranean Sea

The functioning and the results of the monitoring of earthquakes and tsunamis in the Mediterranean Sea in a study by the CAT of the INGV

Evaluating the performance of the Tsunami Warning System in the Mediterranean area operated by the INGV Tsunami Alert Center (CAT-INGV) after its first 4 years, reflecting on the critical issues that emerged, and identifying areas for improvement: these are the purpose of the study "From seismic monitoring to tsunami warning in the Mediterranean Sea" just published in the journal 'Seismological Research Letters', conducted by the National Institute of Geophysics and Volcanology (INGV).

“The tsunami risk in the Mediterranean is poorly known but present even in our seas. Tsunamis are rare events but with enormous destructive potential. The purpose of this study is to analyze the procedures currently in use at the INGV Tsunami Alert Center and identify tools to improve the service, making it faster and more efficient”, explains Alessandro Amato, Head of CAT-INGV and first author of the study. “We have analyzed hundreds of earthquakes around the world and a few dozens in the CAT area, ie, the whole Mediterranean Sea. Some of the strongest earthquakes that occurred between 2017 and 2020, the period of operation of CAT, have generated moderate tsunamis. In a couple of cases, ie in 2017 and 2020 between Greece and Turkey, run-ups as high as two meters were observed; during the recent, magnitude 7 earthquake in Samos, the tsunami produced considerable damage and even one casualty in Turkey. The tsunami warning messages”, continues Beloved,“were sent by the CAT between 7 and 10 minutes after the earthquakes' occurrence, a time sufficient to allow evacuation in almost all coastal areas potentially affected by the tsunami”.

The CAT is part of the Italian national alert system for tsunamis of seismic origin, established in 2017 by the Prime Minister and coordinated by the National Civil Protection Department with the INGV and the Istituto Superiore per la Sicurezza e la Ricerca Ambientale (ISPRA).

The CAT-INGV is a Tsunami Service Provider of the NEAMTWS Intergovernmental Coordination Group (North-East Atlantic, Mediterranean and connected seas Tsunami Warning System) which acts under the coordination of the IOC (Intergovernmental Oceanographic Commission) of UNESCO. In the event of a potential tsunami, the CAT sends alert messages to the Italian DPC and to numerous UNESCO member states of the Euro-Mediterranean area.

“The monitoring of tsunamis of seismic origin”, continues Beloved, “is carried out starting from the real-time analysis of strong earthquakes. We use seismological techniques that allow the rapid calculation of the hypocentral coordinates and the magnitude of each earthquake that occurs at sea or on the coasts of the Mediterranean Sea".

“The study”, Alessandro Amato concludes, “has allowed us to identify some elements that will speed up the calculation procedures by reducing the alert times, while maintaining a good accuracy in the estimates. Finally, the importance of bridging the last segment of the alerting chain was emphasized, allowing the alert messages to reach the citizen. Increased awareness of the tsunami risk and specific preparation of the population are necessary tools for risk reduction”.

 #ingv #cat #tsunami #MediterraneanSea

Link: https://pubs.geoscienceworld.org/ssa/srl/article-abstract/doi/10.1785/0220200437/595804/From-Seismic-Monitoring-to-Tsunami-Warning-in-the?redirectedFrom=fulltext