The South Kermadec Ridge Seamounts are a continuation of the

volcanic A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

island arc Island arcs are long archipelago, chains of active volcanoes with intense earthquake, seismic activity found along convergent boundary, convergent plate tectonics, tectonic plate boundaries. Most island arcs originate on oceanic crust and have re ...

, formed at the

convergent boundary A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a ...

where the Pacific Plate subducts under the Indo-Australian Plate. The subducting Pacific Plate created the

Kermadec Trench The Kermadec Trench is a linear ocean trench in the south Pacific Ocean. It stretches about from the Louisville Seamount Chain in the north (26°S) to the Hikurangi Plateau in the south (37°S), north-east of New Zealand's North Island. Togethe ...

, the second deepest

submarine trench Oceanic trenches are prominent, long, narrow topographic depressions of the ocean floor. They are typically wide and below the level of the surrounding oceanic floor, but can be thousands of kilometers in length. There are about of oceanic t ...

, to the east of the islands. The

seamounts A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly a ...

lie along the western aspect of the undersea Kermadec Ridge, which runs southwest from the

Kermadec Islands The Kermadec Islands ( ; ) are a subtropical island arc in the South Pacific Ocean northeast of New Zealand's North Island, and a similar distance southwest of Tonga. The islands are part of New Zealand. They are in total area and uninhabit ...

towards the

North Island The North Island ( , 'the fish of Māui', historically New Ulster) is one of the two main islands of New Zealand, islands of New Zealand, separated from the larger but less populous South Island by Cook Strait. With an area of , it is the List ...

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

and northeast towards

Tonga Tonga, officially the Kingdom of Tonga, is an island country in Polynesia, part of Oceania. The country has 171 islands, of which 45 are inhabited. Its total surface area is about , scattered over in the southern Pacific Ocean. accordin ...

( Kermadec-Tonga Arc). This area of the Kermadec Arc - Havre Trough is a relatively young oceanic arc-back-arc system as it became active in the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

. The seamounts include: * Speight Knoll * Oliver Knoll * Haungaroa Seamount * Kuiwai Seamount * Cole Seamount * Ngātoroirangi Seamount * Sonne Seamount * Kibblewhite Seamount * Gill Seamount **Situated in the middle of a deep basin (3000m deep) in the Havre Trough, to the west of Kibblewhite and actually closer to the Lau-Colville Ridge than the Kermadec Ridge **Basalt age 1.1 ± 0.4 Ma * Yokosuka Seamount **To west of Brothers situated on an elevated basal plateau (2500m deep) * Rapuhia Seamount **To west of Brothers * Gilianes Seamount **To west of Brothers * Brothers Seamount * Healy ** Two calderas in a elongated complex with the largest caldera being 3 x 4 km ***This is believed to have been formed in the 1360 ± 75 CE eruption ** Cotton ***Satellitic cone to Healy at south west end of complex * The Silents ** Silent I SeamountJohn H. Latter, Edwards F. Lloyd, Ian E.M. Smith, and Simon Nathan. ()
New Zealand's volcanoes: Kermadec Islands
''. Volcanic Hazards Working Group, Civil Defence Scientific Advisory Committee. ** Silent II Seamount * The Rumbles ** Rumble I Seamount ** Rumble II West Seamount ** Rumble II East Seamount ** Rumble III Seamount *** Largest of the chain of Rumble seamounts ***Eruptions on: ****9 July 1958 ****16 January 1963 ****15 October 1973 ****15 June 1986 ****2 July 2008 ** Rumble IV Seamount ** Rumble V Seamount * Lillie Seamount **Lillie is north of Rumbles IV and V * Tangaroa Seamount * Clark Seamount *

Whakatāne Seamount Whakatāne ( , ) is a town located in the Bay of Plenty Region in the North Island of New Zealand, east of Tauranga and northeast of Rotorua. The town is situated at the mouth of the Whakatāne River. The Whakatāne District is the territori ...

References

{{Reflist Seamount chains Seamounts of New Zealand Volcanism of New Zealand Ecoregions of New Zealand Geography of the Kermadec Islands Volcanoes of New Zealand