Mount Sinabung (Indonesian: Gunung Sinabung, Karo: Deleng Sinabung) is a Pleistocene-to-Holocene stratovolcano of andesite and dacite in the Karo plateau of Karo Regency, North Sumatra, Indonesia, from the Lake Toba supervolcano. Many old lava flows are on its flanks and the last known eruption, before recent times, occurred 1200 years before present, between 740 - 880 CE. Solfataric activities (cracks where steam, gas, and lava are emitted) were last observed at the summit in 1912; recent documented events include an eruption in the early hours of 29 August 2010 and eruptions in September and November 2013, January, February and October 2014. A pyroclastic flow in May 2016 killed seven people. Between 2013 and 2014, the alert for a major event was increased with no significant activity. On 2 June 2015, the alert was again increased, and on 26 June 2015, at least 10,000 people were evacuated, fearing a major eruption. The long eruption of Mount Sinabung is similar to that of Mount Unzen in Japan, which erupted for five years after lying dormant for 400 years. A major eruption began on 10 August 2020.