Ora Caldera

The Ora Caldera is a Permian supervolcano in the Southern Alps of northern Italy. This 42 km and 40 km caldera was formed by a supereruption 277–274 million years ago that produced more than 1000 km3 of rhyodacitic-rhyolitic ignimbrite. The ignimbrite from this eruption forms the 10 to 1350 m Ora Formation, which represents the youngest eruptive unit of the Athesian Volcanic Group.