Lake Toba, Indonesia is a supervolcano which was the site of
a massive supervolcanic eruption estimated at VEI 8 that occurred 69,000 to 77,000 years ago, representing a climate-changing event. It is the largest known explosive eruption on Earth in the last 25 million years.
It is believed by some scientist to have caused the Toba Catastrophe Theory, resulting in a 'bottleneck' in early human populations.
The region is most definitely still very active with continuing seismic and volcanic activity.
What would be the precursors to a repeat of a Lake Toba super-eruption?