Alert level raised for volcano that caused largest eruption on Earth in 5,000 years

The alert level for a volcano below New Zealand's biggest lake was raised from zero to one on Tuesday after almost 700 small earthquakes were detected below it. The Taupo volcano caused the largest eruption on Earth in the past 5,000 years when it exploded 1,800 years ago. This is the first time that its alert level has been raised.