The term “tsunami” is made up of the Japanese words for “harbour” (tsu) and “wave” (nami) and describes massive waves in which the entire water column is set in motion (United Nations, n.d.). In 2015, the United Nations declared 5 November as World Tsunami Awareness Day (WTAD) to raise public awareness and draw attention to the destructive power of tsunamis, promote community resilience and support progressive risk reduction strategies (UNDRR, n.d.).

This year’s WTAD aims to draw attention to the unequal impact of tsunamis: The poorest and most vulnerable populations are often the hardest hit by tsunamis. More than 700 million people living in low-lying areas and small island states are on the frontline of these extreme maritime events (UNDRR, 2022). In addition to poverty reduction, the provision of disaster risk reduction knowledge is crucial to save lives in the event of a tsunami. Tsunami early warning systems can only be effective if the population is aware of the tsunami risk and knows what to do in an emergency. To this end, it must be ensured that vulnerable population groups have equal access to information and evacuation routes.

Causes of tsunamis

Tsunamis are mainly triggered by earthquakes, volcanic eruptions or landslides (Jascova, 2021). However, not all earthquakes lead to tsunamis, but only those in which either large masses of material fall into the water or which occur underwater with a magnitude of at least 6.5 and at a maximum depth of 70 km and are accompanied by vertical movements of the seabed. A magnitude of 9.0 was measured during the major earthquake in eastern Japan in 2011. This earthquake triggered a tsunami with record wave heights of 40 metres, killing more than 18,000 people (Kutty, 2022).

Tsunamis are rare, but when they do occur, they are often deadly – in the last century they have claimed the lives of more than 260,000 people. The worst tsunami disaster by far occurred in 2004 in the Indian Ocean and claimed 230,000 lives in 14 countries (United Nations, n.d.). The UNESCO Tsunami Warning Centre for the Pacific has since responded to an average of 7 tsunami events per year (McVeigh, 2022).

Tsunamis in Europe: an underestimated danger

When it comes to tsunamis, many people think of faraway countries such as Indonesia, Japan or Chile – and rightly so, as the Pacific Ring of Fire volcanic belt is notorious for its tsunamis. But tsunamis also occur in Europe, and there have been around 300 in the Mediterranean region since 1600 BC (Centro Allerta Tsunami, 2021). However, awareness of the danger of tsunamis has been forgotten in many places in Europe. Increased awareness and preparation are necessary, especially as “rising sea levels significantly increase the impact of tsunamis” – according to UNESCO tsunami expert Bernardo Aliaga (McVeigh, 2022).

Coastal cities in the Mediterranean must become “tsunami fit” The tricky thing about tsunamis in the Mediterranean is that due to the relatively small size of the Mediterranean, the evacuation time in some places is very short (20 minutes). According to UNESCO, the risk of a catastrophic tsunami in the Mediterranean within the next 30 years is high (McVeigh, 2022). Dr Jörn Lauterjung from the German Research Centre for Geosciences even stated that “the potential magnitude of a tsunami in the Mediterranean may well be comparable to the catastrophic event in the Indian Ocean in 2004. This is because earthquakes in the Mediterranean region can reach magnitudes of 7.5 to 8, meaning that wave heights of five to six meters are within the realm of possibility” (ESKP, n.d.).

Tsunami early warning systems

Tsunami early warning systems play a crucial role in disaster preparedness. They can accurately and quickly transmit information to initiate the evacuation of coastal areas and save lives (Jacova, 2021). Tsunami early warning systems are based on two pillars, technology and communication strategy. A network of measuring stations is installed in the sea to record seismic activity and GPS data. The data from these measuring stations is then sent to warning centers via satellites. Emergency communication is carried out based on the data received by the warning centers.

Various channels such as radio, internet, or SMS are used to inform the public. However, communication via these channels is not crisis-proof. Difficulties such as power outages, loss of the radio network, or other problems can occur. A study by the Japanese Ministry of Internal Affairs and Communications found that in 2011, 35% of people in the areas affected by the tsunami in Japan could not be reached via emergency communication by radio.

This is where communication and warning by sirens come into play. Due to their robustness and ability to operate on emergency power, sirens are a reliable warning tool that is essential for the coordination of rescue operations. In addition, sirens also offer the advantage of a “wake-up function” at night.

Kockum Sonics is an expert in large-scale siren alerting and warning systems. We support you in all phases from planning to installation and maintenance of a reliable tsunami early warning system. In August 2022, we installed 2 Delta 6 sirens in Minturno, Italy, to prepare the community for a possible tsunami.

Reliable tsunami early warning systems are essential to minimise the number of fatalities in such disasters. Immediate evacuation to higher areas is necessary. The United Nations Office for Disaster Risk Reduction (UNDRR, n.d.) launched the WTAD initiative – the #GetToHighGround campaign – in 2022 with exactly this goal in mind. People are to be sensitised by participating in exercises, such as a run along a tsunami evacuation route. UNESCO is calling for comprehensive tsunami preparedness by 2030, and nations are called upon to improve the resilience and preparedness of coastal cities.

Sources information:

Centro Allerta Tsunami. (2021). Tsunami in Mediterranean Sea. Retrieved November 2, 2023 from: https://cat.ingv.it/en/know-and-defend/tsunami-hazard/tsunami-in-mediterranean-sea

ESKP. (n.d.). Tsunami risk in the Mediterranean Sea. Retrieved November 2, 2023 from: https://www.eskp.de/en/natural-hazards/tsunami-risk-in-the-mediterranean-sea-935107/

European Spatial Planning Observation Network. (2005). Europe: tsunami hazard map.  Retrieved November 2, 2023 from: https://www.preventionweb.net/files/3831_TsunamihazardN3.jpg

Jacova, Z. (2021, October 6). About tsunami and the role of warning systems. Retrieved November 2, 2023 from: https://tsunamiday.undrr.org/news/about-tsunami-and-role-warning-systems

Kutty, N. (2022, November 1). Here’s how Japan is using technology to mitigate disasters. Retrieved November 2, 2023 from: https://tsunamiday.undrr.org/news/heres-how-japan-using-technology-mitigate-disasters

McVeigh, K. (2022, June 23). Marseille, Alexandria and Istanbul prepare for Mediterranean tsunami. Retrieved November 2, 2023 from: https://www.theguardian.com/environment/2022/jun/23/marseille-alexandria-and-istanbul-prepare-for-mediterranean-tsunami

UNDRR. (2023). World Tsunami Awareness Day. Retrieved October 31, 2023 from: https://tsunamiday.undrr.org/

UNDRR. (n.d.). A new WTAD initiative #GetToHighGround. Retrieved October 31, 2023 from: https://tsunamiday.undrr.org/gettohighground-campaign

United Nations. (n.d.). World Tsunami Awareness Day.  Retrieved November 2, 2023 from: https://www.un.org/en/observances/tsunami-awareness-day

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