Tsunamis

Tsunamis are giant waves that are produced when a large volume of water is displaced in an ocean or large lake by an earthquake, volcanic eruption, underwater landslide or meteorite. Between 1998-2017, tsunamis caused more than 250 000 deaths globally, including more than 227 000 deaths due to the Indian Ocean tsunami in 2004.  

Tsunamis can travel thousands of kilometres with speeds up to 800 kilometres per hour. Once they reach the coast, they can have devastating impacts on the community. Successive crests can arrive at intervals of every 10 to 45 minutes and wreak destruction for several hours.

More than 700 million people live in low-lying coastal areas and Small Island Developing States exposed to extreme sea-level events including tsunamis.

Resilient infrastructure, early warning systems, and education is critical to saving people and protecting their assets against tsunami risk in the future.

Drowning is the most significant cause of death due to tsunamis. Injuries from debris account for many of the health care needs in the immediate aftermath of the disaster. Falling structures and waters full of swirling debris can inflict crush injuries, fractures, and a variety of open and closed wounds.

The risk of communicable diseases depends on the size, health status and living conditions of the population displaced by the tsunami. The population could be at risk of water-borne diseases and respiratory diseases due to crowding in temporary shelters and inadequate water and sanitation, as well as vaccine-preventable diseases if there is a low vaccination coverage rate prior to the disaster.

Survivors of tsunamis often also face short- and long-term mental health effects due to loss of family, property, livestock or crops. The immediate health concerns after the rescue of survivors following a natural disaster are drinking water, food, shelter and medical care for injuries.

The magnitude of the physical and human costs from tsunamis can be reduced if adequate emergency prevention, preparedness, response and recovery measures are implemented in a sustainable and timely manner. 

WHO works with Member States to build resilient and proactive health systems that can anticipate the needs and challenges during emergencies so that they are more likely to reduce risks and respond effectively when needed.

As the health cluster lead for global emergencies, WHO works with partners to respond to:

• ensure appropriate food supplementation; 
• restore primary care services, like immunization, child and maternal health, and mental health;
• assemble mobile health teams and outreach;
• conduct epidemic surveillance, early warning and response;
• call for emergency funding to support health action.