[2] While bathymetry of Lake Rotoiti is consistent with volcanic vents being present,[3] they could be in an area of collapse subsidence outside the north western margins of the Rotoiti Caldera itself.

[2][a] It erupted 100 cubic kilometres (24 cu mi) of magma[5] that is used in the recent stratigraphy of much of the northern North Island.

[6][7][8][9][10] It was formed in the larger paired eruption with the lesser Earthquake Flat vents linked by tectonic interaction across the length of the Ōkataina Caldera.

[11][5] The series of eruptions was about 50,000 years ago, with the resulting widespread Rotoiti ignimbrite and several layers of Rotoiti/Rotoehu tephra/brecca/ash giving challenges in consistent dating.

[b][12][13][14][15][16]: 188–90 It was subsequently infilled by later eruptive activity to a depth of over 2 km (1.2 mi).