It has been the source of vigorous volcanic activity during the past several thousand years that was dominated by dacitic explosive eruptions, with the largest being VEI-6.

The area of the anvil-shaped island, including fringing islets and rocks mainly in the northeast, but also a few smaller ones in the southeast, is 29.38 km2 (11 sq mi).

Although Raoul is the only island in the Kermadec group large enough to support settlement, it lacks a safe harbour, and landings from small boats can be made only in calm weather.

Obsidian of the same type has been found at early Māori sites at Shag River / Waihemo and Tai Rua, Otago on the South Island of New Zealand.

[4] The last regular occupants, Tom Bell and his wife Frederica, spent thirty-six years on the island before the New Zealand government evacuated them in 1914.

[5] A landing party sent to investigate the island found out how hasty the evacuation of the Bells was – a 1914 calendar was still pinned to the kitchen wall and the family's furniture, cutlery, and child's toys had remained in place.

[6] From 27 May to 16 June 1917, the German raider Wolf, under the command of Korvettenkapitän Karl August Nerger, anchored in the protected bay to undertake engine overhaul and maintenance.

[5] The New Zealand government has permanently staffed Raoul Island since 1937 until the evacuation of staff at the beginning of 2020 due to uncertainties around the COVID-19 pandemic.

Each team undertook 12-month expeditions to the island to provide three hourly weather reports[citation needed] and once daily radiosonde flights using hydrogen filled balloons at 10:30 am.

A Royal New Zealand Air Force P-3 Orion made an overflight on 21 March to provide further information on how safe it was to approach Green Lake.

The volcanologists aboard decided the area was still unsafe, and that the crater lake had risen by about 8 metres (26.2 ft) compared to measurements taken on 17 March.

[11] They were able to undertake a limited search, but decided that it was extremely unlikely that Kearney survived given the amount of devastation in the area around Green Lake.

The Braveheart began the journey back to the mainland on 25 March, with three of the DOC workers staying on the island to continue research.

Also on board were Kearney's sister, Merryn McDermott; three representatives of the Ngāti Kurī iwi; and Chris Carter, the Minister of Conservation.

[18] Located on an active margin between two tectonic plates, the Kermadec Islands also experience frequent earthquakes, the most recently significant of which occurred at 19:28:31 UTC on 4 March 2021.

[19] The epicentre occurred south of Raoul and measured 8.1 on the moment magnitude scale, and as such is classified as a 'major' earthquake by the United States Geological Survey.

[21] More recently on 22 October 2011 at 05:57:17 NZST a Magnitude 7.4 earthquake originating at 28.941S 176.045W at a depth of 39 km occurred according to the United States Geological Survey.

People were advised to avoid sightseeing and remain on alert in case the earthquake had generated a tsunami, however by mid-morning warnings had lifted.

[29] The island is about 1,100 km (680 mi; 590 nmi) northeast of Auckland and its location means it is a convenient earthquake and tsunami monitoring station for several Pacific nations.

[38] Denham caldera's long axis is parallel to the tectonic fabric of the Havre Trough that lies west of the volcanic arc.

He arrived on the 2nd and was occupied till 24 July, during which time he frequently had to move the ship on account of the rough weather experienced.

William Grant Milne and John MacGillivray, naturalists on board the Herald, made a small collection of plants on Raoul.

It is just far enough south that the occasional fertile coconut from Polynesia that washes up on shore and takes root will not survive in the longterm due to a lack of warmth.

[45] Currently, landbirds on the island include the Kermadec red-crowned parakeet (Cyanoramphus novaezelandiae cyanurus), the Australasian harrier, pūkeko, tūī and several introduced species.

The Department of Conservation eradicated rats and cats between 2002 and 2006, following which red-crowned parakeets soon returned naturally, presumably from the Herald Islets, 2–4 km (1.2–2.5 mi) away.

[48][49] There are numerous invasive plant species on the island and a large scale weeding programme involving teams of DOC workers and volunteers has been under way for a number of years in an attempt to eradicate them.