Near-field tsunami early warning and emergency planning in the Mediterranean Sea

Abstract

The new European project <em>Near-field Tsunami Early Warning and Emergency Planning in the Mediterranean Sea</em> (NEARTOWARN) faces the need to develop operational tsunami early warning systems in near-field (local) conditions where the travel time of the first tsunami wave is very short, that is less than 30 min, which is a typical case in the North East Atlantic and the Mediterranean Sea region but also elsewhere around the globe. The operational condition that should be fulfilled is that the time of tsunami detection, plus the time of warning transmitting, plus the time of evacuation should not exceed the travel time of the first tsunami wave from its source to the closest evacuation zone. To this goal the time to detect of the causative earthquake should be compressed at the very minimum. In this context the core of the proposed system is a network of seismic early warning devices, which activate and send alert in a few seconds after the generation of a near-field earthquake, when a seismic ground motion exceeding a prescribed threshold is detected. Then civil protection mobilizes to manage the earthquake crisis but also to detect and manage a possible tsunami through a geographical risk management system. For the tsunami detection the system is supported by tide-gauges of radar type, a database of presimulated tsunami scenarios, and a local tsunami decision matrix. The island of Rhodes in the eastern termination of the Hellenic Arc and Trench has been selected for a pilot and operational development of the local tsunami warning system given that the island is a highly popular tourist destination, historically it was hit by large tsunamigenic earthquakes and was recently the master test-site for the pan-European FP6 tsunami research project <em>Tsunami Risk ANd Strategies For the European Region</em> (TRANSFER).

Bodrum–Kos (Turkey–Greece) Mw 6.6 earthquake and tsunami of 20 July 2017: a test for the Mediterranean tsunami warning system

“…It is believed that the earthquake ground shaking is the first warning message for the coastal communities in the area emphasizing the importance of tsunami awareness and education for coastal communities (e.g., Synolakis and Okal 2005;Satake 2014). The components of tsunami warning systems in the near-field conditions of the Mediterranean Basin have been discussed by a number of authors among which are Ozel et al (2011), Papadopoulos andFokaefs (2013), andNecmioglu (2016).…”

“…For most of the Eastern Mediterranean, tsunami hazard is a local (near-field) phenomenon and while the international and intergovernmental tsunami warning system (i.e., NEAMTWS) addresses the requirements for basinwide tsunami threats, special focus is necessary for nearfield tsunami threat due to its short arrival time (e.g., Synolakis and Kong 2006;Synolakis and Bernard 2006;Papadopoulos and Fokaefs 2013). The near-field tsunami threats are a challenge for tsunami warning systems around the world because of the short tsunami travel times (e.g., 15-20 min) and incapability of the current technologies to accurately estimate earthquake magnitudes in such a short time (e.g., Ozaki 2011).…”

Potential deployment of offshore bottom pressure gauges and adoption of data assimilation for tsunami warning system in the western Mediterranean Sea

“…Due to such high seismicity and existing records of tsunami occurrences, tsunami warning systems have been developed for the Mediterranean basin in the framework of the NEAMTWS (North East Atlantic, Mediterranean and Connected seas Tsunami Warning System) since 2005 (Tinti et al 2012;Papadopoulos and Fokaefs 2013;Papadopoulos 2015;IOC 2015;Necmioglu and Özel 2015;Necmioğlu 2016;Okal et al 2009;Synolakis and Bernard 2006;Satake 2014). Starting from 2017, several countries (i.e., France, Greece, Italy, and Turkey) are equipped with national tsunami warning centers and act as Tsunami Service Providers (TSPs).…”

Design and challenges for a tsunami early warning system in the Marmara Sea

“…These conditions are the main difference with a tsunami early warning system at the regional level. The proposed system for the Marmara Sea, as a modification to Papadopoulos and Fokaefs (2013), is strongly coupled with the IEEW system, also to address the possibility of an earthquake-triggered submarinelandslide-generated tsunami. In the proposed system, a tsunami warning would be disseminated automatically 1 min after the highest threshold of the IEEW with three votes has been received.…”

“…The temporal boundary conditions of a tsunami early warning system is clearly described in Papadopoulos and Fokaefs (2013). According to them, the operative efficiency of a tsunami warning system in near-field conditions depends on the times needed for seismic signal communication, t S , and for evacuation, t E , where each is composed by more than one time components.…”