Lake Segara Anak  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 , 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. 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 . 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 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.