The Tonga Geological Services reported that a thermal anomaly at Home Reef was identified in satellite data at 0115 on 4 December. Thermal anomalies persisted at least through 13 December. The Maritime Alert Level was raised to Orange (the second highest level on a four-color scale) and mariners were advised to stay 4 km away from the island, the Aviation Color Code remained at Green (the lowest color on a four-color scale), and the Alert Level for residents of Vava’u and Ha’apai remained at Green (the lowest color on a four-color scale). A comparison of satellite images from 7 and 12 December showed that a new lobe of lava had flowed to the NE, expanding the coastline. There was also a thermal anomaly over the central part of the island.

Geological Summary. Home Reef, a submarine volcano midway between Metis Shoal and Late Island in the central Tonga islands, was first reported active in the mid-19th century, when an ephemeral island formed. An eruption in 1984 produced a 12-km-high eruption plume, large amounts of floating pumice, and an ephemeral 500 x 1,500 m island, with cliffs 30-50 m high that enclosed a water-filled crater. In 2006 an island-forming eruption produced widespread dacitic pumice rafts that drifted as far as Australia. Another island was built during a September-October 2022 eruption.

Sources: Tonga Geological Services, Government of Tonga, Copernicus