Segara Anak is a
crater lake
Crater Lake ( Klamath: ) is a volcanic crater lake in south-central Oregon in the Western United States. It is the main feature of Crater Lake National Park and is a tourist attraction for its deep blue color and water clarity. T ...
in the caldera that formed during the
explosive volcanic eruption of Mount Samalas in 1257. The caldera is next to
Mount Rinjani
Mount Rinjani ( Sasak: ''Gunong Rinjani'', ) is an active volcano in Indonesia on the island of Lombok. Administratively the mountain is in the Regency of North Lombok, West Nusa Tenggara ( Indonesian: ''Nusa Tenggara Barat'', NTB). It rises t ...
on
Lombok Island
Lombok, is an island in West Nusa Tenggara province, Indonesia. It forms part of the chain of the Lesser Sunda Islands, with the Lombok Strait separating it from Bali to the west and the Alas Strait between it and Sumbawa to the east. It is rou ...
in
Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
. "Segara Anak" means "child of the sea" and refers to the blue lake's resemblance to the sea. The volcanic cone Gunung Barujari is at the eastern end of the lake and is responsible for its crescent shape. The lake temperature is , which is higher than normal for a
lake
A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...
at its altitude. Hot
magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...
below the lake is responsible for this anomaly. Gas bubbles escape from the lake floor, helping the lake to have a
pH of 7–8.
The surface of Segara Anak is above mean sea level (AMSL) and is Indonesia's second-highest caldera lake with an active volcano. The peak of Gunung Baru Jari is AMSL. The lake covers , with dimensions of , and has a maximum depth of .
Fish breeding
There were no fish in Segara Anak. In 1969, volcanologists from the
Geological Society of London
The Geological Society of London, known commonly as the Geological Society, is a learned society based in the United Kingdom. It is the oldest national geological society in the world and the largest in Europe, with more than 12,000 Fellows.
Fe ...
examined the lake and recommended the cultivation of fish. In 1985, the Nusa Tenggara Barat provincial government began breeding fish in the lake. The fish bred rapidly and the lake became home to millions of
tilapia
Tilapia ( ) is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes (formerly all were "Tilapiini"), with the economically mos ...
and
carp
The term carp (: carp) is a generic common name for numerous species of freshwater fish from the family (biology), family Cyprinidae, a very large clade of ray-finned fish mostly native to Eurasia. While carp are prized game fish, quarries and a ...
. Segara Anak is today a popular spot for fishing, and some locals make a living from this.
Mount Samalas
The estimated height of Mount Samalas before its
1257 eruption was . According to a 2013 study, the eruption destroyed the mountain by ejecting up to of
Dense rock equivalent
Dense-rock equivalent (DRE) is a volcanologic calculation used to estimate volcanic eruption volume. One of the widely accepted measures of the size of a historic or prehistoric eruption is the volume of magma ejected as pumice and volcanic ash, k ...
or of rock into the atmosphere.
Deadly 13th-Century Volcano Eruption
/ref> The eruption was one of the largest during the last few thousand years, with a probable Volcanic Explosivity Index
The volcanic explosivity index (VEI) is a scale used to measure the size of explosive volcanic eruptions. It was devised by Christopher G. Newhall of the United States Geological Survey and Stephen Self in 1982.
Volume of products, eruption c ...
of 7. The eruption may have been the cause of decreased global temperatures for a few years and may have even been a triggering factor for the Little Ice Age
The Little Ice Age (LIA) was a period of regional cooling, particularly pronounced in the North Atlantic region. It was not a true ice age of global extent. The term was introduced into scientific literature by François E. Matthes in 1939. Mat ...
.
See also
* List of drainage basins of Indonesia
This is a list of river catchment areas, also known as drainage basins, in Indonesia.
Based on the National River Basin Classification map, Indonesia has a total of 42,210 river basins organized as a basis for determining watershed management poli ...
References
{{reflist
Segara Anak
Segara Anak
Landforms of West Nusa Tenggara
Landforms of Lombok
Drainage basins of Lombok