Reporoa Caldera

The Reporoa Caldera is a 10 km by 15 km caldera in New Zealand's Taupo Volcanic Zone. It formed some 230,000 years ago, in a large eruption that deposited the approximately 100 km³ Kaingaroa Ignimbrites. It contains three rhyolitic lava domes (Deer Hill, Kairuru and Pukekahu) and the active Reporoa geothermal field. The Waiotapu geothermal area is just north of the caldera rim, and the Broadlands thermal area is to the south. The Waikato River runs through the southern half of the caldera.

In April 2005, a large hydrothermal explosion occurred in a cow paddock within the caldera, creating a 50-metre crater. A similar explosion happened in the area in 1948, and smaller explosions have happened in the years between.