Tsunamis are rare, powerful and unpredictable natural hazards, with devastating consequences for coastal populations caught in their path. The vast majority are caused by earthquakes in active seismic areas and occur along a limited range of inhabited shores around the world (Figure 1). In total, 16 major tsunamis killed 250,900 people in 21 countries between 1996 and 2015, according to EM-DAT records.
Tsunamis are the deadliest type of major natural disaster on the planet in terms of the proportion of victims killed. This high level of mortality explains why World Tsunami Awareness Day is being inaugurated on November 5, 2016. Mathematical projections undertaken for this report underline that the threat to human life from tsunamis is increasing at a time when substantial reductions in global disaster mortality (and the numbers of people affected) are key targets of the Sendai Framework for Disaster Risk Reduction adopted by UN Member States in March, 2015. Tsunamis also pose a significant threat to critical infrastructure, including nuclear power plants and airports. These increasing risks demonstrate the need for a commensurate effort to reduce potential tsunami impacts.
Key recommendations are:
• Regional and international disaster preparedness policies should prioritise areas where the largest numbers of people are vulnerable to tsunami events, and take into account how rapid demographic changes and rising sea levels can increase relative levels of exposure;
• The substantial risks related to nuclear installations on high-risk coastlines should also be of great concern when planning for future tsunami disasters;
• Tsunami early warning systems, risk information, education and preparedness are all needed to guide local populations and visitors on how to react after an earthquake, with evacuation routes clearly sign-posted.