Lake Toba (Sumatra) tuff features

Lake Toba was formed by a massive volcanic eruption that occurred roughly 74,000 years ago during the Pleistocene epoch. The resulting deposit of fine-grained volcanic ash and rock fragments collapsed into a massive caldera, which eventually filled with water to create the lake.

The Toba eruption is classified as an 8 on the Volcanic Explosivity Index (VEI), making it one of the largest known explosive eruptions in Earth's history. Some scientists theorize it caused a multi-year volcanic winter that dramatically affected early human populations.

Lake Toba is a massive geological feature located in the northern part of the island of Sumatra, Indonesia. The immense caldera is roughly 100 kilometers long and 30 kilometers wide, making it the largest volcanic lake in the world.

Yes, geological activity continues around Lake Toba, indicating the underlying magma chamber is still active. This is evidenced by hot springs and the emergence of tuff cones, such as Samosir Island, which pushes up in the center of the caldera.