Humanitarian Health Action

TSUNAMIS - Technical Hazard Sheet - Natural Disaster Profile

The Hazard

Tsunamis are giant sea waves that are produced by submarine earthquake or slope collapse into the seabed.

Tsunamis can travel thousands of miles at 300-600mph with very little loss of energy. They reach the coast with devastating impact on shoreline communities. Successive crests can arrive at intervals of every 10 to 45 minutes and wreak destruction for several hours.

Factors of Vulnerability

Man made factors:

  • Settlement located in low lying coastal areas (direct impact);
  • Lack of tsunami resistant building;
  • Lack of timely warning system and evacuation plan.

Main causes of Morbidity and Mortality

Direct Impact

Deaths occur principally by drowning. Injuries and trauma are few and occur from battering by debris.

Short and long term mental health effects are observed.

Indirect Impact

The impact on the health infrastructures and all lifeline systems is massive and can result in food shortages and the interruption of basic public health services (water, etc).

Foreseeable Needs

Pending an assessment, needs can be anticipated such as: search and rescue, medical assistance, food, water and shelter and maintaining food security over the long term (crops and livestock are likely to be lost).

Don't Forget

A tsunami's occurrence is unpredictable but technological innovations now make it possible to spot them and warn coastal communities at risk for an incoming tsunami.

In the absence of mitigation measures such as community education, warning systems, or structural barriers such as breakwaters, Tsunamis have an important lethal impact.

Inappropriate Response

Medical or paramedical personnel or teams: Do not send them! They would arrive too late. Local and neighbouring health services are best placed to handle emergency medical care to disaster victims.

Field hospitals, modular medical units: Do not send them! This type of equipment is justified only when it meets medium-term needs. It should never be considered unless it is donated.

Household medicines or prescriptions: Do not send them. These items are sometimes medically and legally inappropriate. Consult first WHO's guideline on essential drugs and the local authority of the beneficiary country.

Temporary shelter such as tents: Do not send them! As temporary resettlements in relative houses or in public edifices are by far more appropriate than creating population displacement camps.

Unilateral decision on resource allocation: Do not take it without evidence of needs.

For further information please contact:

WHO Health Action in Crises

Environmental Emergencies Mr J Hueb +(41 22) 791 3553 or

Injuries and Violence Prevention Dr E Krug +(41 22) 791 3535 or

Organization of Health Service Delivery Dr Mechbal +(41 22) 791 2889 or

For further reading:

An Overview of Disaster Management, 2nd ed. Geneva, United Nations Development Programme, Disaster Management Training Programme, 1992.

Coping with Natural Disasters: The Role of Local Health Personnel and the Community. Geneva, World Health Organization, 1989.

Do’s and Don’ts After Natural Disasters. Washington, Pan American Health Organization Press Release, 1998.

Emergency Health Management after Natural Disaster. Washington, Pan American Health Organization Scientific Publication 407, 1981.

Natural Disasters: Protecting the Public’s Health. Washington, Pan American Health Organization Scientific Publication 575, 2000.

Noji E. Public Health Consequences of Disasters. New York, Oxford University Press, 1997.Noji E. Public Health Consequences of Disasters. New York, Oxford University Press, 1997.