The classical tsunami warning methodology mainly addresses tsunamis due to earthquakes depending on the reliable identification of earthquake parameters, which generally dictates >7 min before the initial tsunami warning is issued with acceptable reliability. This may sound a short amount of time, however, such a delay may still be too short to warn the communities at certain coastal locations, where tsunamigenic earthquake sources are close to the shoreline. Not only the historical 1908 Messina Strait earthquake and tsunami, but also recent events such as 2018 Palu, 2018 Anak Krakatau and 2022 Hunga Tonga-Hunga Ha'apai reminded us of the urge the relevant communities to fill the gaps of local/nearfield tsunami warning for multi-hazard monitoring and early warning systems.
In that respect, coastal community tsunami resilience requires an integrated, multi-disciplinary and multihazard-oriented approach, as underlined by the target (g) of the Sendai Framework for Disaster Risk Reduction which aims to increase the availability of and access to multi-hazard early warning systems and disaster risk information and assessments to people by 2030. Local tsunami warning systems configured as part of multi-hazard early warning systems coupled with earthquake or volcano early warning systems could, in theory, reduce the warning time significantly and could help the evacuation process, especially in coastal communities with low awareness of the tsunami threat after a strong earthquake or volcanic activity. In fact, the inadequacy of centralized tsunami warning systems at the local level — based on determination of earthquake parameters — might perhaps be only remedied by having such systems embedded in the National Tsunami Warning Centre (NTWC)-Tsunami Service Provider (TSP) operational framework. This would have to be a close collaboration between dedicated local or community–based tsunami awareness and preparedness programs, where different stakeholders are involved.
Several attempts were made to address this gap, ranging from conceptual systems to pilot implementations. In the meantime, there are also important developments in the publicly available earthquake early warning systems around the globe, and the need to address meteo-tsunamis in the context of tsunami early warning has also been recognised.
The Joint Research Centre (JRC) is closely involved in the work of the UNESCO-Intergovernmental Oceanographic Commission (IOC), contributing to its work in many aspects: from the generation of tsunami scenarios, to the provision of operational tsunami early warning software and inexpensive sea-level devices (IDSL) globally, or initiatives towards establishing Tsunami Ready communities in the Euro-Mediterranean region. The JRC develops innovative technological solutions for disaster risk management, including newly designed sensors and alerting devices for tsunami risk. The Directorate General for European Civil Protection and Humanitarian Aid Operations (DG ECHO) has funded the test of their effectiveness and interoperability during 2018-2021, through the Tsunami Last Mile projects, as implemented first in Greece and Turkey (2018/2019) and in Malta and Indonesia (2020/2021) through “Last Mile” projects. One of the most recent examples of such collaboration in capacity building was the DG-ECHO / UNESCOIOC project “Strengthening the Resilience of Coastal Communities in the North-East Atlantic and Mediterranean Region to the Impact of Tsunamis and Other Sea Level-Related Coastal Hazard (CoastWAVE)“. This initiative started in late 2021, aimed to strengthen the resilience of vulnerable coastal communities in the North-East Atlantic, Mediterranean and its connected seas (NEAM) region to tsunamis and other sea level-related hazard by adapting Global Tsunami Ready Standards and Guidelines and pilot Tsunami Ready within the framework of the ICG/NEAMTWS and providing a sustainable sea-level measurement network. Based on the framework described above, this workshop will bring earthquake, volcano and tsunami early warning experts to discuss in detail the requirements of effective local tsunami warning in the multi-hazard disaster risk mitigation context. The outcome report of the workshop is expected to assist the development of an integrated, truly multi-hazard-oriented coastal community resilience policy brief.