Tsunami

Tsunamis are infrequent, high-impact disasters. Since records began in 1850, tsunamis have been responsible for over 420,000 deaths and billions of dollars of damage. While big tsunamis—like the devastating event in the Indian Ocean in 2004—are very infrequent, there has been on average one tsunami disaster per year. Despite their unpredictable nature, proper pre-disaster planning and post-disaster response can help mitigate their effects.

The event that triggers the tsunami—earthquakes, volcanoes, or landslides—is followed by a violent inundation of debris-laden saltwater into often increasingly populated and ecologically sensitive coastal zones. It is impossible to predict where and when the next tsunami will occur, as the unpredictable geophysical nature of a tsunami compounds issues faced by those charged with planning for an event, as well as the cleanup and reconstruction. Certain characteristics, however, make tsunamis more manageable than other coastal hazards such as cyclones. For example, tsunamis only directly affect a narrow strip in the coastal zone, and there are no physical effects outside the inundation zone. Also, with saltwater inundation, disease outbreaks are less common than with freshwater flooding. As is the case with most disasters, however, the impacts from a tsunami can cascade from local to global scales.

Hazard awareness, informed coastal planning, and community preparation, along with well-maintained early warning systems, are the keys to tsunami risk reduction. While it is impossible to predict the occurrence of a tsunami trigger, scientists and engineers are working to rapidly predict the timing and magnitude of the tsunami in the minutes and hours following an earthquake. These efforts will help with early warning and evacuations, and combined with a solid local educational component, will ultimately reduce the risk in exposed communities.