The eruption, approximately 700 years ago, destroyed their settlements, but there is circumstantial evidence that some of the residents may have escaped the destruction, presumably by waka (canoe).

[6][7] Fears they could be a sign of a looming eruption at nearby Rangitoto Island were allayed by geologists, who said they were caused by fault lines, not volcanic activity.

Archaeological deposits bracketing the ash suggest the eruption prompted a shift from broad-spectrum hunting of forest birds to intensive marine exploitation and horticulture.

In the 1820s many of the islands in the Hauraki Gulf, including Motutapu, were evacuated in response to the threat of Hongi Hika and the Ngāpuhi armed with muskets.

[12] Occasional ventures were made back to former territories in the gulf, sometimes not without consequence, as with when a local fishing party was attacked at Motutapu by Ngapuhi with several casualties.

[13] From 1836 many of the evacuated territories were resettled, and the Ngai Tai remained on Motutapu until the northern part of the island was sold to Tom Maxwell in 1840.

The southern end was purchased by Williamson and Crummer in 1845, but subsequently granted to politician Robert Graham in 1857, with the island increasingly becoming a trip destination – Home Bay Wharf hosted such attractions as whale boat racing, greased pig chasing and hunting.

War broke out in September 1939 and the military population on the island went from 10 to 200, requiring the construction of additional buildings at Administration Bay and at the observation posts.

[11] Geologically, Motutapu comprises Waipapa series greywackes, cherts and argillites, overlaid with Waitemata tertiary sediments, and blanketed in Rangitoto ash.

Stone sources exploited for tool manufacture were largely the local greywacke found on Motutapu and nearby Motuihe, but included obsidians from Great Barrier and Northland, as well as Nelson argillites and basalts from Tahanga.

Emu Bay has the foundations of four separate groups of buildings, remnant plantings and isolated Norfolk pines on high points of the island.

The military structures on Motutapu comprise a largely intact World War II landscape including: the main 6-inch gun emplacement with three gun pits, underground magazines, shelters and stores; the battery observation post, engine and radar rooms; the Emu observation post and engine room for the anti-submarine defences; the ground-level plotting complex with miniature range, plotting and generator rooms; the underground plotting complex with command exchange, radio, plotting generator, battery and fuel rooms, as well as access tunnels and corridors; the search light emplacements and directing station; personnel camps at Administration Bay and the battery; the US Navy magazines north of the causeway and store at Home Bay, and numerous pillboxes to protect the battery from a commando assault.

The natural vegetation of the island was almost totally gone by the middle of the 19th century, due to the volcanic eruption and subsequent settlement activities and pests introductions by both Māori and Europeans.

Following three aerial drops of brodifacoum poison baits on Motutapu and Rangitoto in winter 2009, as of January 2010, rodents, rabbits and stoats appeared to have been successfully eradicated.

[20] Since then a number of native New Zealand species have been translocated to Motutapu including takahē, saddleback and North Island brown kiwi.