So what about Taupo? Now a gorgeous crater lake, it is also responsible for two of the world’s most violent eruptions. Around 1.25 to 1 million years ago, it erupted so powerfully that much of New Zealand’s North Island was completely covered in hot ash.
Unusually for supervolcanoes, though, its most powerful eruptions took place after its initial formation. Around 26,500 years ago, the so-called VEI 8 Oruanui eruption produced pyroclastic flows so extensive that they buried the North Island beneath 200 meters of it (about 660 feet). Significant ash fallout spread around much of the regional Pacific Ocean.
If the same happened again today, it would kill most of the 3.6 million people that live there.
Lake Taupo, as seen from space. NASA
Then, another blast during the year 180, although “just” a VEI 7 blast, produced similarly violent pyroclastic flows that covered an area equivalent to 25 New York Cities. The eruption produced so much ash, the skies over Italy and China turned red.
There have been plenty of blasts in between these dates, and the next eruption at the site is expected to be mildly explosive, but it’ll likely only harm those in the region of the lake. New Zealand authorities note that only three eruptions since the Oruanui event have produced pyroclastic flows.
There is no simple pattern to these eruptions that can give volcanologists any idea as to when it will erupt or even super-erupt again, if at all. Taupo is just too unpredictable, but if it did induce another caldera-forming eruption, it would essentially be the Yellowstone of the Southern Hemisphere in terms of its destructive ability.
The Final Two
Indonesia’s Toba made its debut 1.5 million years ago, but that’s not the eruption we’re interested in here.
Around 73,000 years ago, a colossal blast produced a caldera 100 kilometers (62 miles) long. This eruption manufactured so much volcanic material that the world was thought to have been plunged into a six-year-long volcanic winter.
Within days, South Asia was smothered by an ash layer 15 centimeters (6 inches) deep, with closer areas being buried in ash and pyroclastic flow deposits hundreds of meters deep.
Resurgence at Toba. OregonStateCEOAS via YouTube
This was not just a VEI 8 event. This was the largest volcanic eruption in the last 2.5 million years, and for some time it was thought that it almost brought humanity to the point of extinction – although this has since been questioned.
Worryingly, there is a magma source beneath Toba today that’s the same size as the one beneath Yellowstone, and it’s clearly dynamic – the center of Lake Toba is rising skywards, indicating that the magma beneath is expanding outwards.