Niuafo'ou

Niuafo’ou (50, but only 33 is land) is the most northerly island of the kingdom, 337km NW of Vava’u, nearer Samoa and Fiji than to Tongatapu. It is a volcano on an underwater ridge 190km west of the line of all the other volcanoes of Tonga.

The island is a steep-sided calderas; the rim is over 120m high, rising to Mokotu 250m. The coastline is rocky and steep with no reef, and the few beaches are stony with some black sand. The only landing place is the end of a lava flow at Futu, in the west. All the villages are in the east.

The island ring encloses two lakes. The largest, Vai Lahi, is 23m above sea level, 4km wide, and 84m deep. It has three islands plus a low one which appears when the water level drops. Vai Lahi is separated from the smaller Vai Mata’aho by a wasteland of sand hills and opines. The inner walls of the main Crater Lake and the eastern slopes north of Tongamama’o have dense forest. Forest is also growing slowly over the lava-covered western slopes. Coastal vegetation is found on the entire southern coast. All the rest of the island has coconut palms, trees and mixed agriculture.

Niuafo’ou has been an active volcano for thousands of years. It is a most unusual volcano because there have been two types of eruptions.

Explosions from the craters in the Caldera produce magma. This is surface material carried down by subduction and remelted. Lava flows from long cracks in the outer slopes are deep mantle material pushing up. In 1853 the village of ‘Ahau was destroyed, killing 25 people. Lava flows from eruptions in 1912 and 1929 destroyed all bush and gardens of the western slopes and the village of Futu, and cut off the harbor.

There were eruptions in 1935, 1936, 1943, and the most violent was in 1946.