Tsunami risk in Tonga is rated as extreme. This is because Tonga lies about 200 km west of the Tonga Trench fault zone, where the Pacific Plate subducts beneath the Australian Plate.
Tonga Trench is a potential source for a marine landslide caused by an earthquake or volcanic eruptions which could trigger a tsunami. Tonga is also located within the Ring of Fire that runs around the Pacific Ocean and where most seismic activities occurs.
Historical accounts show that some 20 tsunamis have affected many islands in Tonga. Most tsunami waves have been small (<1m) with little recorded damage.
However, the Niuatoputapu (NTT) tsunami reached maximum height of 16.9m on the southeast coast.
- 9 fatalities and 6 seriously injured
- Government centre destroyed including the hospital, Government staff quaters and offices
- More than 60% of dwelling houses destroyed
- Total estimated cost of damage – TOP$18.2m