How We Tell if a Volcano Is Active, Dormant, or Extinct

The end of December, GNS Science in New Zealand declared that the volcanic unrest at Tongariro that started in 2012 is over.

They lowered the volcanic alert status to Level o (background) and declared that Tongariro was back asleep (even if some steam might persist from the Te Maari vent). So, we can probably consider Tongariro “dormant” again after 3+ years of being an “active” volcano.

It is probably because there are no hard-and-fast definitions for what a volcano is considered active, dormant or extinct.

So, how do we differentiate between active, dormant and extinct volcanoes ???

Geologist Erik Klemetti on this subject >>>>