Rotomahana

Lake Rotomahana is an 800-hectare (2,200-acre) lake in northern New Zealand, located 20 kilometres to the south-east of Rotorua. It is immediately south-west of the dormant volcano Mount Tarawera, and its geography was substantially altered by a major 1886 eruption of Mount Tarawera. Along with the mountain, it lies within the Okataina caldera.

The New Zealand Ministry for Culture and Heritage gives a translation of "warm lake" for Rotomahana, following Hochstetter. Before the 1886 eruption, only two small lakes were present in the current lake's basin. Following the eruption, a number of craters filled over the course of 15 years to form today's Lake Rotomahana. It is the most recently formed larger natural lake in New Zealand, and the deepest in the Rotorua district. The lake's northern shore lies close to the 39 metres (128 ft) lower Lake Tarawera, separated by less than 700 metres (2,300 ft) of terrain that is mostly material from the 1886 eruption. Lake Rotomahana has no natural outlet, and its water level varies by about one meter in response to rainfall and evaporation.

The lake is a wildlife refuge (and was one prior to first contact), with all hunting of birds prohibited. A healthy population of black swan inhabits the lake, and there are efforts underway to ensure the lake's largest island, Patiti Island, is kept pest-free. Recent research confirms Patiti Island is the closest surviving pre-eruption feature on the old lake, i.e. to survive the 1886 eruption, being formerly known as Rangipakaru Hill. There is no public access to the lake, save for the Tourist Track, overland from Lake Tarawera.

The Pink and White Terraces were a natural wonder on the shores of the lake before the 1886 eruption. 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. 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. More recent research reports over 2016-2020 suggest the upper parts of both terraces lie on land and may therefore be accessed for physical evidence the terraces or sections of them survived in their original locations. The 2017- research relied on the journals of German-Austrian geologist Ferdinand von Hochstetter, who visited the lake in 1859. Hochstetter's journals are the only known survey of the terraces before the eruption. 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). 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 Maori tribe on whose sacred ancestral land the Pink and White Terraces are situated. Ground penetrating radar searches were undertaken in 2017 but the equipment failed to penetrate sufficiently deeply to show whether or not the Terraces lay in their surveyed locations. Later Hochstetter survey research refined the Pink, Black and White Terrace locations.

Taken from: https://en.wikipedia.org/wiki/Lake_Rotomahana