In the context of the geological discussion, a high standard hydrophonic survey took place in 2016 and the absolute measurements taken at this time, as lake level varies, are used for baseline.

[2]: 24  Lake Rotomahana has no natural surface outlet, and its water level varies by about one metre in response to rainfall and evaporation.

[11] The now lake floor was mostly dry when surveyed in the period 1886 to 1888 after the eruption,[13] and it is possible to match these observations with current geolocated hydrophonic findings.

As a result it is the most recently formed large natural lake in New Zealand, and at 118 m (387 ft) deep,[4]: 41  the deepest in the Rotorua district.

[19] The eruption process which was basaltic deposited muddy material widely and many metres thick especially to the northeast.

[22] There is an area southwest of Pātītī Island that has a heat flux averaging 13 W/m2 that appears to be in a lake floor crater created in 1886.

The nitrogen load on the lake is stable,[2]: 5  but has high trophic level index inflow from the Okaro catchment via the Haumi Stream.

They were considered to be the eighth wonder of the natural world and were New Zealand's most famous tourist attraction during the 19th century, from c. 1870-1886; but were buried or destroyed by the eruption.

[25] Scientists thought they had rediscovered the lower tiers of the Pink and White Terraces on the lake bed at a depth of 60 metres (200 ft) in 2011.

[27][28][24] The 2017- research relied on the journals of German-Austrian geologist Ferdinand von Hochstetter, who visited the lake in 1859.

[30] Using Hochstetter's field diaries and compass data, a team of New Zealand researchers identified a location where they believe the Pink and White Terraces lie preserved at a depth of 10–15 metres (32–49 ft).

[31] The researchers were hoping to raise funds for a full survey of the area, but any work would first have to be approved by the local Māori tribe on whose sacred ancestral land the Pink and White Terraces are situated.

[39] In 2016 when a scuba team first dove the lake, they found no evidence of a sunken forest or trees, as reported by Fitzgerald off Moura.

[40][41] While there were forests over the pre-eruption Mt Tarawera, Tōtara trees were scattered and only recorded over the western and southern mountain flanks.