Polynesia
What tectonic plate is Tonga on?
Tonga sits entirely on the Tonga Plate.
- Plates
- 1
- M6.5+ quakes since 1900
- 110
- Holocene volcanoes
- 21
- Land area
- 432 km²
Plates under Tonga
Share of Tonga's land area on each plate (PB2002 model, Natural Earth outlines).
Plate boundaries
4 plate boundaries run through or along Tonga: the Tonga-Pacific boundary (convergent, about 19.3 cm/yr), the Niuafo'ou-Australian boundary (divergent, about 8.3 cm/yr), the Tonga-Niuafo'ou boundary (divergent, about 6.2 cm/yr) and the Tonga-Australian boundary (divergent, about 5.5 cm/yr).
- Tonga and Pacific: convergent, 19.3 cm/yr
- Niuafo'ou and Australian: divergent, 8.3 cm/yr
- Tonga and Niuafo'ou: divergent, 6.2 cm/yr
- Tonga and Australian: divergent, 5.5 cm/yr
The fastest of these is the Tonga-Pacific boundary, where the plates move about 19.3 cm/yr relative to each other. That is faster than fingernails grow.
Earthquakes in Tonga
Tonga is one of the most earthquake-prone countries on Earth. The USGS catalog lists 110 earthquakes of magnitude 6.5 or more in or just off Tonga since 1900, which ranks it 14 of 213 countries.
| Earthquake | Magnitude | Year | Depth | Plate |
|---|---|---|---|---|
| Tonga Earthquake | M8.1 | 1919 | 25 km | Pacific |
| Tonga | M8.0 | 1903 | 400 km | Tonga |
| Tonga Earthquake | M8.0 | 2006 | 55 km | Tonga |
| 159 km W of Pangai, Tonga | M7.8 | 1950 | 216 km | Tonga |
| south of Tonga | M7.8 | 1975 | 9 km | Pacific |
| 146 km ESE of Hihifo, Tonga | M7.8 | 1975 | 33 km | Tonga |
Volcanoes in Tonga
The Smithsonian Global Volcanism Program lists 21 volcanoes active in the last 12,000 years in Tonga, the 16th most of any country.
- Tofua Caldera · 515 m Last eruption 2026
- Home Reef Stratovolcano · -10 m Last eruption 2026
- Hunga Tonga-Hunga Ha'apai Caldera · 114 m Last eruption 2022
- Lateiki Stratovolcano · 43 m Last eruption 2019
- Tofua Arc at 18.3°S Stratovolcano · -40 m Last eruption 2019
- Tofua Arc at 20.9°S Stratovolcano · -296 m Last eruption 2017
- West Mata Fissure vent(s) · -1,174 m Last eruption 2009
- Tafu-Maka Fissure vent · -1,400 m Last eruption 2008
Frequently asked questions
What tectonic plate is Tonga on?
Tonga sits entirely on the Tonga Plate.
Is Tonga on a plate boundary?
4 plate boundaries run through or along Tonga: the Tonga-Pacific boundary (convergent, about 19.3 cm/yr), the Niuafo'ou-Australian boundary (divergent, about 8.3 cm/yr), the Tonga-Niuafo'ou boundary (divergent, about 6.2 cm/yr) and the Tonga-Australian boundary (divergent, about 5.5 cm/yr).
Does Tonga get earthquakes?
Tonga is one of the most earthquake-prone countries on Earth. The USGS catalog lists 110 earthquakes of magnitude 6.5 or more in or just off Tonga since 1900, which ranks it 14 of 213 countries. The largest was the M8.1 Tonga Earthquake in 1919.
Are there volcanoes in Tonga?
The Smithsonian Global Volcanism Program lists 21 volcanoes active in the last 12,000 years in Tonga, the 16th most of any country.