Volcano F (Tonga)

Volcano F (also known as Volcano 0403-091) is a submarine volcano in the Tonga Islands of the South Pacific Ocean. It is located 50 km (31 mi) northwest of Vavaʻu, between Late and Fonualei on the Tofua ridge. It is part of the highly active Kermadec-Tonga subduction zone and its associated volcanic arc, which extends from New Zealand north-northeast to Fiji, and is formed by the subduction of the Pacific Plate under the Indo-Australian Plate.

The volcano was first mapped in 2004, and assigned the name "Volcano F". It consists of a large (8.7 x 6 km) caldera with a depth of 670 – 720 m. The caldera walls are 200 – 300 m high, with the highest peak on the rim only 35 m (115 ft) below sea level. The entire volcano rises 1,000 m (3,300 ft) from the sea-floor.