Lake Toba (Indonesian: Danau Toba) is a large natural lake
occupying the caldera of a supervolcano. The lake is about 100 kilometres
long, 30 kilometres wide, and up to 505 metres (1,666 ft) deep. Located in
the middle of the northern part of the Indonesian island of Sumatra, with a surface elevation of about 900
metres (2,953 ft), the lake stretches from 2.88°N 98.52°E to 2.35°N 99.1°E. It is the
largest lake in Indonesia
and also the largest volcanic lake in the
world.[1]
Lake Toba is the site of a
massive supervolcanic eruption estimated at VEI 8
that occurred 69,000 to 77,000 years ago,[2][3][4] representing a climate-changing event.
It is the largest known explosive eruption on Earth
in the last 25 million years. According to the Toba catastrophe
theory, it had global consequences for human populations; it killed
most humans living at that time and is believed to have created a population bottleneck
in central east Africa and India, which affects the genetic make up of the
human worldwide population to the present.[5]
It has been accepted that
the eruption of Toba led to a volcanic winter with a worldwide decrease in
temperature between 3 to 5 °C (5.4 to 9.0 °F), and up to 15 °C
(27 °F) in higher latitudes. Additional studies in Lake Malawi in East Africa show significant
amounts of ash being deposited from the Toba eruptions, even at that great
distance, but little indication of a significant climatic effect in East Africa.