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Segara Anak is a crater lake in the caldera that formed during the explosive volcanic eruption of Mount Samalas in 1257. The caldera is next to Mount Rinjani on Lombok Island in Indonesia. "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 20–22 °C (68–72 °F), which is 5-7 °C (9-13 °F) higher than normal for a lake at its altitude. Hot magma 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.[1]

Segara Anak
Rinjani Caldera.jpg
LocationLombok Island
Coordinates8°25′00″S 116°28′00″E / 8.4166°S 116.4666°E / -8.4166; 116.4666Coordinates: 8°25′00″S 116°28′00″E / 8.4166°S 116.4666°E / -8.4166; 116.4666
Lake typeCrater lake
Basin countriesIndonesia
Surface area11.3 km2 (4.4 sq mi)
Max. depth190 m (620 ft)
Water volume36×10^6 m3 (1.3×10^9 cu ft)
Surface elevation2,004 m (6,575 ft)

The surface of Segara Anak is 2,004 metres (6,575 ft) above mean sea level (AMSL) and is Indonesia's second-highest caldera lake with an active volcano. The peak of Gunung Baru Jari is 2,376 metres (7,795 ft) AMSL. The lake covers 45 square kilometres (17 sq mi), with dimensions of 7.5 by 6.0 kilometres (4.7 by 3.7 mi), and has a maximum depth of 230 metres (750 ft).[2]

Lake Segara Anak featured in 10,000-rupiah banknote.

Mount SamalasEdit

The estimated height of Mount Samalas before its 1257 eruption was 4,200 metres (13,800 ft). According to a 2013 study, the eruption destroyed the mountain by ejecting up to 10 cubic miles (42 km3) of rock into the atmosphere. The eruption was one of the largest during the last few thousand years, with a probable Volcanic Explosivity Index of 7. The eruption may have been the cause of anomalous weather for a few years and may have even been a triggering factor for the Little Ice Age.[3][4][5]

ReferencesEdit

  1. ^ The 2009 eruption of Rinjani volcano (Lombok, Indonesia) Université Libre de Bruxelles (2009)
  2. ^ "Lake Segara Anak: The Charm of Mt. Rinjani's Giant Caldera". 29 November 2016.
  3. ^ Lavigne, Franck; et al. (2013). "Source of the great A.D. 1257 mystery eruption unveiled, Samalas volcano, Rinjani Volcanic Complex, Indonesia". Proceedings of the National Academy of Sciences of the United States of America. 110 (42): 16742–16747. doi:10.1073/pnas.1307520110. PMC 3801080. PMID 24082132.
  4. ^ Hamilton, Garry (19 October 2013). "The lost volcano". New Scientist: 39–41.
  5. ^ [1] bbc article
 
Segara Anak in Panoramic View