Billy Mitchell (volcano)

The last two major eruptions were in 1580 AD ± 20 years and about 1030 AD. They were among the largest Holocene eruptions in Papua New Guinea. Both were explosive eruptions with a Volcanic Explosivity Index of at least 5. The 1580 AD ± 20 years eruption produced pyroclastic flows and probably formed its caldera. The ignimbrite deposit from that eruption, which had a VEI of 6, extends 22 kilometres (14 mi) from the caldera to the coast, and its volume is around 10 cubic kilometres (2.4 cu mi).

Caldera lake

Billy Mitchell caldera lake is about 1,013 m above sea level, has total surface area 3 km² (1.2 sq mi), and the maximum depth approximately 88.3 m. The only fish species in the lake is the eel Anguilla megastoma. Billy Mitchell lake drains into the Tekan River.