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 fast, however, such a delay may still be late for some coastal locations, where the tsunamigenic earthquake sources are located very near to the shoreline. In addition to the historical 1908 Messina Strait earthquake and tsunami, 2018 Palu, 2018 Anak Krakatau and 2022 Hunga Tonga-Hunga Ha'apai are other events that clearly remind us the urge the relevant communities to fill the gaps of local/near-field tsunami warning in the context of multi-hazard monitoring and early warning systems.
In that respect, coastal community tsunami resilience requires an integrated, multi-disciplinary and multi-hazard-oriented approach, as underlined by the target (g) of the Sendai Framework for Disaster Risk Reduction: which aims to substantially 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.