Around 73,000 years ago, super volcano "Toba" erupted and its catastrophic impact still affects people even until today with the onset of global climate change. Now, scientists are finding clues on what triggers them to blow in a new study published in the journal Scientific Reports.
"Toba" Super Volcano Is Not To Blame For Humanity's Near-Extinction
The Toba outburst was the largest volcanic eruption witnessed in history, which covered 2,800 cubic kilometers of the surrounding area in volcanic ash, causing vast amounts of rain in Indonesia and India. So, how exactly these amounts of magma are formed (and why they erupt violently) has been a hot topic of debate amongst scientists for a long time.
It has also been known that volcanoes erupt due to density and compression, and commonly it is a way that Earth can release excess heat from its core. But still, the precise trigger part has remained unsolved.
A group of scholars at Uppsala University and their international colleagues might have found some answers lying in millimeter-sized crystals called quartz crystals entrenched in the volcanic ash and rock.
Quartz crystals grow in magma, and thermodynamically changes before it erupts, which is similar to how tree crust rings record climate change, according to David Budd, lead author of the study from Uppsala University.
"When the settings in the magma change, the crystals respond and produce diverse growth zones that could record changes," he said in a statement. "in view of some problem, that each 'tree ring'-analogue is only a few micrometers across, which is why they are very challenging to analyze in details." "This rock type also often covers a lot of water, which may be released into the magma, creating steam, and in that way, there will be an increase of pressure inside the magma hollow," said Frances Deegan.
"This rapidly increased gas pressure and eventually permitted the magma to rupture the overlying crust, and send thousands of cubic kilometers of magma into the atmosphere."
How Often Do Super Volcanoes Erupt?
Luckily, super volcanoes like these erupt very rarely. Volcanic eruptions are well measured by the Volcanic Exclusivity Index (VEI,) with VEI 7 and VEI 8 eruptions being the most powerful.
Other than Toba, these are some of the most massive super volcano eruptions in history:
- La Garita Caldera erupted roughly around 27.8 million years ago, and released 5,000 cubic kilometers of magma.
- Huckleberry Ridge in Yellowstone had a bulk expulsion of 2,500 cubic kilometers about 2.1 million years ago.
- Atana Ignimbrite in Chile erupted about 4 million years ago, also emitted 2,500 cubic kilometers.
- In 1815, the Tambora volcano on Sumbawa Island in Indonesia erupted in what is considered the largest and most devastating eruption in recorded history ever. It was a VEI 7 on the VEI scale, but a projected death toll of 100,000 people from the effects, and itcaused a global volcanic winter season.
- Although some famous eruptions such as Mount Vesuvius (Pompeii in 79 AD) and Mount St. Helens in 1980were very small in comparison to these super volcanic ones.
Researchers say that Toga's eruption was so colossal it was close to wipe out the entire humanity. It's a matter of when, not if, super volcanoes erupt once more.
