Tofua (Tonga)

Status Normal Eruption 2014 515m
Caldera (Subduction zone / Oceanic crust (< 15 km))

The low, forested Tofua Island in the central part of the Tonga Islands group is the emergent summit of a large stratovolcano that was seen in eruption by Captain Cook in 1774. The first Caucasian to set foot on the 515-m-high island was Capt. William Bligh in 1789, just after the renowned mutiny on the "Bounty." The summit contains a 5-km-wide caldera whose walls drop steeply about 500 m. Three post-caldera cones were constructed at the northern end of a cold fresh-water caldera lake, whose surface lies only 30 m above sea level. The easternmost cone has three craters and produced young basaltic-andesite lava flows, some of which traveled into the caldera lake. The largest and northernmost of the cones, Lofia, has a steep-sided crater that is 70 m wide and 120 m deep and has been the source of historical eruptions, first reported in the 18th century. The fumarolically active crater of Lofia has a flat floor formed by a ponded lava flow.

Steam rises from Lofia cone on the north side of the caldera lake of Tofua volcano in this 1990 aerial photograph. Recent tephra from pyroclastic cone mantles the caldera rim to the NW. The walls of the 5-km-wide caldera drop steeply about 500 m. Three post-caldera cones were constructed at the northern end of a cold fresh-water caldera lake, whose surface lies only 30 m above sea level. Tofua was seen in eruption in 1774 by Captain Cook, and Captain William Bligh landed on the island in 1789, just after the renowned mutiny on the "Bounty."

Aerial photo by Tonga Ministry of Lands, Survey, and Natural Resources, 1990 (published in Taylor and Ewart, 1997).

Last updated 2019-08-04 00:28:02