Billy Mitchell (volcano)

Billy Mitchell is a pyroclastic shield, an uncommon type of volcano in the central part of the island of Bougainville, just north-east of the Bagana Volcano in Papua New Guinea. It is a small pyroclastic shield truncated by a 2 km wide caldera filled by a crater lake.^[2] It is generally thought to be named after Billy Mitchell, a 20th-century United States Army general who is sometimes regarded as the father of the United States Air Force, although the exact origin of this claim is not known.^[3]

Billy Mitchell (volcano)
The dark-colored caldera lake of Billy Mitchell is at right, above an ash plume originating from Bagana.
Highest point
Elevation	1,544 m (5,066 ft)
Coordinates	6°06′S 155°13′E
Geography
Billy Mitchell (volcano) Bougainville, Papua New Guinea
Parent range	Emperor Range
Geology
Mountain type	Pyroclastic shield
Volcanic zone	Solomon Islands
Last eruption	1580 ± 20 years

Billy Mitchell
Billy Mitchell
Location	Bougainville Island
Coordinates	6.1°S 155.21667°E / -6.1; 155.21667 (Billy Mitchel (crater lake))
Type	crater lake
Basin countries	Papua New Guinea
Surface area	~3 square kilometres (1.2 sq mi)[1]
Max. depth	~90 metres (300 ft)[1]

Background

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 second of these eruptions likely had an effect on worldwide temperature, lowering it by 0.2-0.3 degrees celsius for a year or two after the event.^[4][5] 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).^[1]

The volcano is considered dormant as its last eruption was over 350 years ago. ^[6]

Caldera lake

Billy Mitchell caldera lake is about 1,013 m above sea level, has a total surface area of 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. ^[7] Billy Mitchell lake drains into the Tekan River.^[6]

See also

• List of volcanoes in Papua New Guinea
• Mount Billy Mitchell (Chugach Mountains)
• Timeline of volcanism on Earth