Volcano Live
volcanolive.com
Niuafo'ou Volcano | John Seach
Tonga
15.60 S, 175.63 W
summit elevation 260 m
shield volcano
Niuafo'ou is a shield volcano with a summit crater.
The island is circular in shape and 20 miles in circumference. Niuafo’ou volcano, is located in the centre of the northern Lau Basin, and represents one of the few subaerial volcanoes from a back-arc setting. The island is almost completely surrounded with cliffs.
In 1999 a new hot spring was found in the NE part of the central caldera at Niuafo’ou Volcano. The island was temporarily evacuated during the 1946 eruption, and currently has a population of over 700 people. The island is reported to contain the largest coconuts in the Pacific.
The centre of the island contains a caldera with a lake (Vai Lahi) which is 90m deep and 25m above sea level. The undated caldera-forming eruption involved summit collapse and left behind a 14 sq km, water-filled caldera. The post-caldera phase has involved intra-caldera explosive and extra-caldera effusive activity. At least 12 eruptions have been recorded in the last 150 years, the most recent major one occurring in 1946 when the island was evacuated.
Two types of eruptions have been recorded at Niuafo'ou volcano.
Effusive lava flows from flank fissures contrast with explosive eruptions through the caldera lake.
1886 Eruption
The eruption of Niuafo'ou volcano in 1886 was preceded by 24 hours almost continuous earthquakes, lightning and thunder. People abandoned six villages and went to the town of Futoo on the western side of the island. Small geysers broke out on the shores of the lake.
On 31st August a pillar of flame shot into the air to a height of 2000 ft, and were visible from Keppel Island 100 miles away. The eruption ejected hot water from the lake, stones and choking dust which covered the whole island. Seven villages were completely destroyed. A 200 ft high cone emerged from the lake. Hot stones were ejected from the crater and burnt coconut trees.
The eruption lasted 10 days, and then the craters only emitted smoke and steam.
Further reading
Reay, A., et al. "Lavas from Niuafo'ou Island, Tonga, Resemble Ocean–Floor Basalts." Geology 2.12 (1974): 605-606.
Bryan, W.B., Stice, G.D. and Ewart, A., 1972. Geology, petrography, and geochemistry of the volcanic islands of Tonga. Journal of geophysical research, 77(8), pp.1566-1585.
Regelous, Marcel, et al. "Mantle dynamics and mantle melting beneath Niuafo’ou Island and the northern Lau back-arc basin." Contributions to Mineralogy and Petrology 156.1 (2008): 103-118.
Niuafo'ou Volcano Eruptions
1985, 1959?, 1947?, 1946, 1943, 1935-36, 1929, 1912, 1887, 1886, 1867, 1853, 1814.