Lava lake

Lava lake at Kīlauea
(Kūpaianaha, 1986)

A lava lake is an accumulation of liquid lava in a depression, usually a volcanic crater . Sometimes the term is also applied to a frozen lava lake. If the lava is located in a volcanic crater with a direct supply of the lava from below, this is referred to as a primary lava lake , whereas if the lake was fed by above-ground inflows, it is referred to as a secondary lava lake .

Most active lava lakes are composed of basaltic melt, except for Mount Erebus , which contains a phonolithic melt.

behavior

The rising red-hot lava begins to cool immediately when it reaches the surface and forms a thin black crust. Since this crust becomes heavier than the hotter liquid lava, it is swallowed again immediately, which has already been compared with the subduction in plate tectonics . If the supply of fresh magma or hot gases is greater, the lake, or parts of it, begins to boil violently, up to the point of ejection of slag and bombs .

Many of the currently active lava lakes have been active for a long time, but the height of the lava level can vary greatly. Sometimes the lake can overflow, as is often the case at Kīlauea and is rather harmless. At Nyiragongo in 1977 a crack opened in the crater rim and the lava lake ran out. The fast flowing lava flow claimed 600 lives.

Examples

The Kīlauea volcano in Hawaii has repeatedly produced lava lakes in various craters. The last major event with the sinking and refilling of the lava lakes in the Puʻu ʻŌʻō and Halemaʻumaʻu craters took place in March 2011. Their lava levels are currently fluctuating considerably.

Active lava lakes

There are currently (as of 2015) only a few active lava lakes on earth.

Africa

Erta Ale (Ethiopia): 80 m × 90 m diameter, active since 1906
Nyiragongo (Virunga National Park, Congo): intermittently active since 1977

Antarctic

Mount Erebus (Antarctica): 60 mx 45 m, active since at least 1972

Atlantic Ocean

Holuhraun lava field ( Bárðarbunga , Iceland): 400 m × 100 m, active since October 2014

Middle and South America

Masaya (Nicaragua):
Villarrica (Chile): intermittently active since 2009

Pacific Ocean

Puʻu-ʻŌʻō -crater ( Kīlauea , Hawaii ): since 1987 intermittent lava lakes
Halemaʻumaʻu crater (Kīlauea, Hawaii): active since 2008, its lava level fluctuates around 90 m
Ambrym (Vanuatu): Crater of the (Mbwelesu-) Marum
Ambrym (Vanuatu): Benbow crater

Halemaʻumaʻu : crater with lava lake (Hawaii, 2016)
Halemaʻumaʻu: Lava lake in the caldera of Kīlauea (Hawaii, 2012)
Erta Ale : Lava lake in a pit crater (Ethiopia, 2001)
Ambrym : Lava Lake (Vanuatu, 2009)
Benbow on Vanuatu
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Halemaʻumaʻu: Time-lapse image of the lava lake in the crater (Hawaii, 2016)

Masaya crater with glowing lava
Nyiragongo lava lake
Mount Erebus from space

Frozen lava lakes

Several solidified lava lakes can be found in the Fort Rock Basin , in the US state of Oregon, within Pleistocene tuff rings . Also at Dimmuborgir Lake Myvatn in northern Iceland is the remains of a solidified lava.

More recent examples can be found at Kilauea, where, among other things, the Kīlauea-Iki crater was filled in by a 116 m lava flow in 1959 and then slowly solidified. This is also an example of a secondary lava lake . In this lava lake, among other things, the temperature profile and the magmatic differentiation during the solidification process could be observed and analyzed through drilling . It took almost 400 days at the Alae lava lake , which is only 20 m deep , until it completely solidified and the temperature fell below 1000 ° C, the solidus temperature of basalt.