Coastal regions are important focus of development, are densely populated and therefore, are very vulnerable to hazards as tsunamis. One crucial aspect of disaster risk reduction is the efficient functioning of Early Warning Systems which are owned by Member States and require a high degree of international and multilateral cooperation, under the governance of IOC. They are designed according to well-defined operational standards which are uniformly implemented across the broad range of activities and projects. As tsunamis may affect different regions of the world at the same time, strong regional cooperation is encouraged.
Tsunamis occur more commonly in the Pacific Ocean, due to the seismic and volcanic activity at tectonic plate boundaries along the Pacific Ring of Fire. The Pacific Tsunami Warning Centre (PTWC) was created in 1949 as a response to the 1946 tsunami generated in the Aleutian Islands that devastated Hilo, Hawaii. The Chilean earthquake of 1960 is the strongest quake registered in the world and the tsunami that it provoked affected zones as distant as Hawaii. The Intergovernmental Coordination Group for the Pacific Tsunami Warning and Mitigation System (ICG/PTWS) – formerly ITSU – was created as a subsidiary body of IOC in 1965 to support Member States in the implementation of effective measures of tsunami warning and mitigation.
Even if the Pacific coasts are particularly susceptible to tsunamis, all regions of the world may be affected by destructive tsunamis. The earthquake in Lisbon, Portugal, in 1755 was one of the most deadly earthquakes in history and was followed by a tsunami that highly impacted the city. This event, that almost destroyed Lisbon, promoted a change in the paradigm in the study of earthquakes which represented the starting point of modern seismology.
The tsunami in the Indian Ocean in 2004 has been one of the most deadly tsunamis in history and triggered one of the worst disasters in the past century. Unfortunately, the region did not have an early warning system and around 230.000 people died due to the tsunami. In response of this tragic event, IOC received the mandate from the international community to coordinate the establishment of regional tsunami early warning systems in the Indian Ocean, the Mediterranean and the Caribbean. This mandate was expressed in important meetings as World Conference on Disaster Risk Reduction (Kobe, Japan, 2005) and the Phuket Ministerial Meeting on Regional Cooperation on Tsunami Early Warning Arrangements in Thailand, 2005. As a result, the Intergovernmental Coordination Group for the Indian Ocean Tsunami Warning and Mitigation System (ICG/IOTWS) and the Intergovernmental Coordination Group for the Tsunami Early Warning and Mitigation System in the North-eastern Atlantic, the Mediterranean and Connected Seas (ICG/NEAMTWS) were set up.
Large zones of the Caribbean region are vulnerable to earthquake and landslide induced tsunamis. During the last 500 years, the Caribbean has experienced devastating tsunamis that have caused incalculable damage. Considering the great risk from tsunamis in the Caribbean and the lessons learned from the tsunami in the Indian Ocean in 2004, the Intergovernmental Coordination Group for the Tsunami and other Coastal Hazards Warning System for the Caribbean Sea and Adjacent Regions (ICG/CARIBE EWS) was established in 2005.
ICGs support Member States in the implementation of end-to-end tsunami early warning systems, including the emission of understandable tsunami warnings. Tsunami warning services are provided by the Pacific Tsunami Warning Centre (PTWC) in Hawaii for the Pacific Coasts and as interim for the Caribbean Sea and the Indian Ocean. The West Coast and Alaska Tsunami Warning Centre (WC/ATWC) provides tsunami information products for USA territories in the Caribbean region; and the Japan Meteorological Agency (JMA) for the South China Sea and as interim for the Indian Ocean as well.
At the national level, each Member State is responsible for issuing warnings to its own citizens through their National Tsunami Warning Centres (NTWC) or the designated authorities. These warnings are based either on the NTWC’s own analysis of the situation, on the advisory messages received from PTWC, WC/ATWC and JMA (and some other sources), or on a combination of all. Even if tsunamis are relatively infrequent events, they might be more recurrent than is usually understood in the community. In fact, due to the changing patterns in population settlements and the related increase of population living in coastal zones, the collective memory of these events is not properly transmitted among generations. In this respect, education for community preparedness through both formal and non-formal channels plays a critical role for the reduction of risks. IOC promotes as well the improvement of preparedness measures and community-based, people-centred mitigation activities.