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| Samosir Island is formed from the super-eruption of Toba Volcano (photograph was taken by the writer in 2016) |
The research about Toba-scale eruption has been being attracted by many geologists and earth science’s scientists. This occurs because of the formation of Toba Lake which was formed by the activity of two major tectonic lineaments [1]. Geologically speaking, these two major tectonic lineaments which are the Eurasian and Australian are one of the most active lineaments in the world in term of seismic activity. As a result, the Indonesian archipelago is composed by many active volcanoes including the Toba Volcanoes.
However, the writer which is also the local citizen of North Sumatera – the province which Toba Lake is located – seems reluctant as the region nearby the Toba Lake is merely a highland. More importantly, the concern about the “Toba volcano” is active was coined by the theory of Toba catastrophe theory which stated about the super-eruption happened in 75 thousands years ago [2]. According to the theory, the Toba Eruption or Toba Event was dated by the presence of potassium argon and it was the fourth eruptions.
But, the theory suggested that the eruption had caused long-term of climatic change. Although it resulted super eruption which produced airborne volcanic materials to the atmosphere, “the eruption did not appear in switching the climate in general into a new mode” according to Oxford’s archaeologist [3]. Nevertheless, one thing that is certain is the formation of Toba Lake and it is surely formed because of the tectonic-volcanic activities.
The interesting point coined out by the theory is the changing of climate. The 73 ka eruption affected three areas which were Eastern and Southern Africa, India and South-East Asia regions based on the simulation involving the Mt. Pinatubo eruption in 1991 [4]. Hence, the results found that the human society was not affected by the eruption indicating there could be slight changing in the climate. The questions are how it did not affect the climate at all? And how the conditions of the Earth at that time?
The world-map published by Princeton University suggested that the Indonesian archipelago particularly the western and central area of Indonesia is joined together to the Asia Continent connected throughout the Malay Peninsula [5]. Based on the map, the change could be slight because the environment attributes which are simulated are the monsoon and temperature. Due to the ice caps spread in the northern Asia and Europe, the monsoon and temperature anomalies which exceed above normal term became stable after five to six years since the eruption [4].
To conclude, the thing that super-eruption of Toba Volcano occurred 75 thousands years ago was beyond normal. The temperature was abnormal for five to six years after eruption prevail one to two minus Kelvin which affected daily minimum temperatures accounted for 10 centigrade for months [4]. However, living things at that time particularly the Neanderthals (or Neandertals) had survived by adaptation process including staying in the cave. However, the eruption has shown that the Young Toba Tuff is considered as super volcano.
References
[1] M. Williams, "The ~ 73 ka Toba super-eruption and its impact: History of a debate," Quaternary International, no. 258, pp. 19-29, 2012.
[2] W. "Toba catastrophe theory," Wikipedia, 29 July 2017. [Online]. Available: https://en.wikipedia.org/wiki/Toba_catastrophe_theory. [Accessed 30 July 2017].
[3] J. Amos, "Toba super-volcano catastrophe idea 'dismissed'," BBC, 30 April 2013. [Online]. Available: http://www.bbc.com/news/science-environment-22355515. [Accessed 30 July 2017].
[4] C. Timmreck, H.-F. Graf, D. Zanchettin, S. Hagemann, T. Kleinen and K. Kruger, "Climate response to the Toba super-eruption: Regional changes," Quartenary International, no. 258, pp. 30-44, 2012.
[5] P. U. P. "100000–11000 years ago - Princeton University Press," [Online]. Available: press.princeton.edu/chapters/haywood/s2_9519.pdf. [Accessed 30 July 2017].