Lake Toba is one of the tourist destinations in Indonesia which has amazing charm. Apart from its natural beauty that spoils the eye, Lake Toba is also preserved its authenticity by local residents, starting from the culture of the community to its socio-culture.

Maybe you have seen or heard the story of the formation of Lake Toba, either in television series or in fairy tales in the community. One of the popular tales is that Lake Toba started with a young man named Toba who was looking for fish in the river and then found a large goldfish that turned into a beautiful woman. The young man named Toba then married the woman on the condition that Toba was prohibited from mentioning the origin of the woman. They then have a child who is named Samosir. Once upon a time, Toba was angry with Samosir and accidentally shouted “you fish,” who unconsciously mentioned the origin of Toba’s wife. Disasters began to hit, storms, winds, water jets submerged the area. Toba drowned under the water that inundated the area which was eventually named Lake Toba, meanwhile, Samosir followed his mother’s instructions to escape to a high place so he could survive the disaster. Where Samosir saved himself is called Samosir Island. The woman who came from a goldfish changed her form into a fish again and plunged into Lake Toba.

That’s the fairy tale that circulates about the formation of Lake Toba. However, scientifically and historically, Lake Toba is not a young man named Toba who was eaten because of his words that broke his oath. Lake Toba is a lake formed by the eruption of Mount Toba. Mount Toba is an active volcano that has a high explosive power. Based on area.sindonews (06/07/2018) Mount Toba has erupted three times, namely 800,000 years ago where the eruption formed a caldera (a basin due to the fall of land after a volcanic eruption) in the south of Lake Toba which includes the Porsea and Parapat areas. The second eruption was around 500,000 years ago where this eruption formed a caldera to the north of Lake Toba, which is the area between Haranggol and Silalahi. The third eruption is the last eruption and the most powerful eruption of Mount Toba’s activity, which is about 73,000 to 75,000 years ago where this eruption is said to be one of the causes of changes in world civilization. This is due to the charge released by Mount Toba in the form of magma of more than 2,800 cubic km with an explosion scale of around 8.0 Volcanic Explosivity Index (VEI).

The eruption of Mount Toba has a very strong explosive power of 26,000 megatons of TNT, more than the explosive power of the Hiroshima and Nagasaki nuclear bombs (0.015 megatons TNT) and the Krakatau eruption (150 megatons TNT). Based on area.sindonews (06/07/2018) the height of the eruption reached 50 km and the ash material spread throughout the earth’s atmosphere to cover the sunlight entering the earth for several years. As a result, the earth’s temperature at that time dropped to 3-5 degrees Celsius. Apart from generating a large tsunami, the eruption of Mount Toba also resulted in the mass death of humans and several other species of living things. From several research results that have been conducted, this volcanic eruption is thought to have shrunk more than 60% of the human population at that time, which is about 60 million people.

After erupting, this mountain formed a caldera which then filled with water and eventually became the largest lake in Southeast Asia. This lake is known as Lake Toba. Geographically, Lake Toba is surrounded by 7 districts in North Sumatra, namely Samosir, Simalungun, Humbang Hasundutan, Dairi, Karo and Toba Samosir, and North Tapanuli Regencies. Lake Toba is a lake with a caldera covering an area of ​​1,145 square kilometers, therefore, Lake Toba is placed as the largest lake in Southeast Asia and the largest volcanic lake (lake formed by volcanic eruptions) in the world.

Source :goodnewsfromindonesia