November 5 2025 will mark the tenth annual World Tsunami Awareness Day. The event this year is dedicated to the theme 'Be Tsunami Ready: Invest in Tsunami Preparedness'. This intended to raise awareness of the risks presented by tsunamis, and promote investment in in tsunami early warning, evacuation mapping, risk education, and regular drills reduce mortality, limit disruption, and protect development gains along coasts.
World Tsunami Awareness Day was adopted as an annual event in December 2015, as part of the Sendai Framework for Disaster Risk Reduction, a program intended to run from 2015 to 2030, which aims to increase the world's resilience to natural disasters, by providing United Nations member states with actions intended to protect development gains from natural disasters. The Sendai Framework is intended to run in concert with the Paris Agreement on climate change. The Sendai Framework was intended as the successor to the Hyogo Framework for Action, which was founded in 2005, in response to the Boxing Day Tsunami of 2004, which killed over 227 000 people in coastal communities around the Indian Ocean.
The word tsunami derives from the Japanese 津波 (tsu-nami), meaning 'harbour wave'. The term refers to the large waves which occur when large water movements enter an enclosed coastal area, such as harbours. The initial water movements are typically caused by geological events such as Earthquakes, volcanoes, landslides, or even meteor impacts, and can be almost invisible when crossing deep water, but become deadly when entering shallow and confined spaces. A tsunami typically takes the form of a sudden drop in sea level, often exposing areas of the seabed not normally exposed, followed by an inrush of water which sweeps over low-lying areas, often sweeping away coastal communities.
The Boxing Day Tsunami of 2004 was caused by a Magnitude 9.2 Earthquake off the west coast of northern Sumatra, and caused waves up to 30 m high to sweep over coastal communities in Indonesia, Thailand, Sri Lanka, the Maldives, and parts of India, with fatalities recorded as far away as South Africa.
The 2011 Tōhoku Tsunami was caused by a Magnitude 9.0 Earthquake off the coast of the Oshika Peninsula, Japan, and caused waves over 40 m high travelling at speeds of over 700 km per hour to overwhelm communities as far as 10 km from the coast. This led to over 19 750 deaths, and the destruction of the Fukushima Nuclear Power Plant.
The 1883 Krakatoa eruption (in which the Krakatoa volcano essentially exploded) caused a tsunami within the Sunda Straight (which separates Sumatra from Java) with a maximum recorded height of 46 m, washing away coastal communities on both islands, and many smaller ones, and killing over 36 000 people, with fatalities recorded as far away as Sri Lanka.
The Minoan eruption, which occurred around 1600 BC, is destroyed much of the island of Santorini, and triggered a tsunami which swept over the island of Crete, destroying the Minoan civilisation which was based there. It has been suggested that the waves also reached other civilisations around the Eastern Mediterranean, including Egypt, although this has been hard to prove.
The Storegga Submarine Landslide, which occurred some time between 6225 and 6170 BC, displaced about 3500 km³ of material along a 290 km stretch of the continental shelf off the coast of Norway. This triggered a tsunami which scoured about 600 km of Scottish coastline, with waves reaching about 29 km inland, wiping out the Mesolithic civilisation which dwelt there. It has also been suggested that tsunamis caused by this event may have swamped Doggerland, the former landbridge which connected Great Britain to the European continent, although it is now generally accepted that this was drowned by rising waters associated with melting glaciers at the end of the Pleistocene.
No known example of a meteorite causing a tsunami has been recorded in Human history. However, the Chicxulub Impact at the End of the Cretaceous is thought to have caused waves up to 600 m high to hit the coast of what is now Louisiana, causing major sediment redistributions from Texas to Florida.
Tsunamis, therefore, present a series threat to coastal, and in extreme cases non-coastal communities and infrastructure. Human survival in the face of such events is often dependent on good early warning systems; part of the reason that the 2004 Boxing Day Tsunami was so deadly was that the Indian Ocean did not have a tsunami warning system similar to that which had been in place in the Pacific since 1965. One of the achievements of the Hyogo Framework being the establishment of the Indian Ocean Tsunami Warning and Mitigation System in 2006.
The concept of World Tsunami Awareness Day 2025 is to promote five courses of action to protect coastal communities from the dangers of tsunamis.
The first of these calls on national and local governments, finance ministries, development banks, insurers, and private investors to commit multi-year financing for tsunami preparedness and multi-hazard early warning systems.
The second calls upon coastal municipalities, community groups, school systems, tourism operators, and media partners to elevate tsunami readiness, enrol in recognized community frameworks, and showcase real-world success stories.
The third calls for disaster management authorities, educators, non-governmental organisations, and local media to co-develop and distribute tsunami risk-communication toolkits, and to institutionalise regular public education and community drills aligned with readiness indicators.
The fourth calls upon mayors, civil protection leads, school principals, health and port authorities, and faith/youth leaders to serve as visible champions for tsunami preparedness in their communities.
Finally, the fifth course of action calls upon research institutions, technology providers, and public agencies to promote international awareness and knowledge-sharing of disaster-risk-reduction technologies adapting and piloting them in high-risk coastal areas.
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