Lake Rotomahana
| Lake Rotomahana | ||
|---|---|---|
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| Lake Rotomahana with Mount Tarawera in the background | ||
| Geographical location | Rotorua Lakes District , Bay of Plenty Region , North Island , New Zealand | |
| Tributaries | various small streams (brooks) | |
| Drain | no | |
| Islands | Patiti Island | |
| Data | ||
| Coordinates | 38 ° 15 '47 " S , 176 ° 26' 43" E | |
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| Altitude above sea level | 337 m | |
| surface | 7.95 km² | |
| length | 6.2 km | |
| width | 2.8 km | |
| scope | 27.5 km | |
| Maximum depth | 125 m | |
The Lake Rotomahana is a volcanic crater in the District Rotorua Lakes region Bay of Plenty on the North Island of New Zealand .
geography
The at an altitude of 337 m lies Lake Rotomahana , located 20 kilometers southeast of Rotorua , on the southwest side of the volcano Mount Tarawera . The lake is part of the larger complex of the Okataina Caldera , a volcano that has had six major eruptions in the past 10,000 years .
With a length of 6.2 km and a maximum width of 2.8 km, the up to 125 m deep lake extends over an area of 7.95 km 2 . Since the lake has no drain, its water level varies depending on the amount of rainfall. Centrally located in the lake is Patiti Island , also known as Banded Island . It rises up to a height of 404 m from the lake. Another, but nameless, island is located in the eastern part of the lake. Depending on the water level, it becomes an island or peninsula.
geology
Before 1886 there was the much smaller Rotomahana at the location of today's lake and to the east of it the even smaller Rotomakariri lake . On June 10, 1886, a 9 km long and up to 180 m deep crater, extending in a south-westerly direction, formed from the area of Mount Tarawera over the two small lakes at that time to Waimangu . The eruptions of the eruptions were so massive and accompanied by steam explosions as well as the ejection of boulders that a 5 cm thick layer of fine volcanic ash formed over an area of around 2000 km 2 , which from all activities together grew up to 6 m thick in places, other sources give ash heights of up to 14 m.
Before this eruption, which killed 116 people, the area around the Rotomahana consisted of an extremely active hydrothermal field with springs of boiling water and geysers. Silicate sintered terraces , known as Pink and White Terraces , were popular destinations for tourism at the time. The steam explosions in the area of the Rotomahana are said to have carried steam and ash clouds up to a height of 10–13 km and were ultimately responsible for the formation of the crater, in which today's lake gradually formed through precipitation.
In the western area of the lake, at the foot of the 470 m high Uruakorako Hill, the Steaming Cliffs are located , which still bear witness to the hydrothermal activities of the area.
Pink and White Terraces rediscovered
125 years after the Pink and White Terraces were filled in by the volcanic eruption and sank into the lake, geologists from the research institute GNS Science found fragments of the terraces by chance at the bottom of the lake. The scientists who researched the lake floor and found some faults in the bottom, also came across remnants of the terraces, which they investigated further photographically three years later after evaluating their data. They could definitely identify parts of the Pink and White Terraces on the lake floor.
Flora and fauna
The banks and slopes of the lake's caldera are overgrown with trees and bushes, as is Patiti Island . Rainbow trout live in the lake and can also be fished. A population of black swans can also be found on the lake.
literature
- IA Nairn : Rotomahana — Waimangu eruption, 1886: base surge and basalt magma . In: New Zealand Journal of Geology and Geophysics . Volume 22, No. 3 , 1979, pp. 363–378 , doi : 10.1080 / 00288306.1979.10424105 (English, online [PDF; 3.5 MB ; accessed on June 3, 2018]).
- PC Whiteford, DJ Graham : A thermal area beneath Lake Rotomahana outlined by sediment temperature measurements . In: International Geothermal Association (Ed.): Proceedings 15th NZ Geothermal Workshop . Bochum 1993, p. 213–217 (English, online [PDF; 389 kB ; accessed on June 3, 2018]).
Web links
Individual evidence
- ↑ a b c d Topo250 maps . Land Information New Zealand , accessed June 3, 2018 .
- ↑ a b c d e Whiteford, Graham : A thermal area beneath Lake Rotomahana outlined by sediment temperature measurements . 1993, p. 213 .
- ↑ Coordinates and longitudes were determined using Goggle Earth Pro, Version 7.3.1.4507, on June 3, 2018.
- ↑ Malcolm McKinnon : Okataina caldera and its neighbors . In: Te Ara - the Encyclopedia of New Zealand . Ministry for Culture & Heritage , May 25, 2015, accessed June 3, 2018 .
- ^ Nairn : Rotomahana — Waimangu eruption, 1886: base surge and basalt magma . In: New Zealand Journal of Geology and Geophysics . 1979, p. 363 .
- ^ Nairn : Rotomahana — Waimangu eruption, 1886: base surge and basalt magma . In: New Zealand Journal of Geology and Geophysics . 1979, p. 365 .
- ↑ a b Robin Wylie : A natural wonder lost to a volcano has been rediscovereds . BBC , April 28, 2016, accessed June 3, 2018 .
- ^ Nairn : Rotomahana — Waimangu eruption, 1886: base surge and basalt magma . In: New Zealand Journal of Geology and Geophysics . 1979, p. 364 .
- ↑ A natural wonder rediscovered after 125 years. In: Science -ORF. ORF, June 10, 2011, accessed on June 3, 2018 .
- ↑ Lake Rotomahana Trout Fishing . NZ Fishing , accessed June 3, 2018 .