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There have always been tsunamis across the world but the 2004 event in the Indian Ocean, which caused over 250 000 casualties, showed how devastating they can be. Likewise, the 2011 tsunami, which killed more than 19 000 people in Japan, underlined the fact that even for a well-prepared country the consequences can be dramatic.
While the earthquakes causing tsunamis cannot be predicted, if they do not occur too close to the coast and information is communicated quickly it is possible to provide early warnings and mitigate the impact. However, an extensive infrastructure is needed for such a rapid warning system.
The JRC started working on tsunamis after 2004 with the aim of estimating the consequences should one occur. Its tsunami assessment modelling system couples sophisticated seismic and hydraulic modelling methods with communication technologies to alert humanitarian and civil protection bodies.
By minimising the time between tsunami detection and the sending of alerts, the system could save thousands of lives.
‘We developed a global tsunami calculation system that identifies where a tsunami is most likely to hit and sends SMS and email messages to users registered in the Global Disaster Alert and Coordination System (GDACS) website, which alerts the humanitarian community to ongoing disasters,’ explains project coordinator Alessandro Annunziato of the JRC’s European Crisis Management Laboratory in Italy.
‘More recently, we started developing a network of sensors designed to identify tsunamis in the Euro-Mediterranean region, the North Atlantic and the Black Sea. One of these devices correctly identified the tsunami that occurred on 26 October 2018 in the Ionian Sea, as a consequence of a magnitude 6.8 earthquake off Zakynthos Island in Greece,’ he continues.
This work fits into a larger portfolio of research on disaster risk management. Early-warning systems research is part of the JRC's contribution to the UN’s Sendai Framework for Disaster Risk Reduction.
Estimating consequences
The JRC’s system has four main components. The first is a global database containing 136 000 tsunami scenarios, with epicentres chosen based on historical events.
It provides a preliminary estimate of potential consequences as soon as the epicentre is known, identifies locations at risk and predicts wave height.
The online calculation system uses the same model as the database but is automatically initialised with the actual epicentre and magnitude as soon as an earthquake is detected.
A tsunami analysis software tool supports real-time analysis of events to facilitate rapid estimation of the consequences. It allows for comparison of the database scenarios and online calculations with sea-level measurements from sensors developed by the JRC.
A tsunami alert device, a prototype of which is operating in Setúbal, Portugal, comprises a panel equipped with data receivers, a display, a siren and a loudspeaker. It can be activated by GDACS or local sea-level measurement systems to deliver warnings in at-risk areas in the event of tsunamis or other dangerous waves. This system will be tested in 2019 in a large exercise (the Last Mile Project) that will take place on the island of Kos, Greece and at Bodrum, Turkey, which were hit in 2017 by a tsunami that caused extensive damage to both locations.
According to Annunziato, the widespread take-up of the device could be increased by using the display as advertising space when it is not needed for alerts.
Staying alert
As Annunziato says, the usefulness of tsunami alert systems is not evident until an event occurs and systems that may have lain dormant for years need to be activated.
‘We only start talking about tsunamis after important tragedies, but a few years later everything is forgotten,’ he says. ‘Floods and forest fires occur where everybody can see them, so it is considered useful to spend huge amounts. Nobody discusses the need for continuous maintenance of aeroplanes because the risk of not doing so is felt and understood. In the case of tsunamis, maintaining the systems requires continual expenditure, which is not currently on the agenda. I suggest that young people, who are sensitive to environmental problems, inform themselves about tsunamis because one day they could be the ones deciding whether to keep these systems operational,’ Annunziato concludes.
Maintenance of alert systems is only part of a shift towards a long-term perspective on disasters. Ultimately, as advocated in the global UN Sendai Framework for Disaster Risk Reduction, it is better to avoid disasters altogether through prevention policies. As the work on tsunamis clearly shows, upfront investment in prevention and preparedness is paid back many times over when disaster hits.