The Tonga Geological Services reported ongoing and consistent activity at Home Reef during 11-21 March. A lava dome just SW of the central part of the island was visible in an 11 March satellite image; this 80 m W-E, 100 m N-S feature had not changed in size since the previous view. Thermal anomalies were ongoing at least through 19 March and were at mostly low levels, though occasionally they were characterized as moderate. Infrasound data also indicated continuing minor eruptive activity. The Maritime Alert Level remained at Orange (the third level on a four-level scale), and mariners were advised to stay at least 2 nautical miles (3.7 km) away from the island. The Aviation Color Code remained at Yellow (the second level on a four-level scale), and the Alert Level for residents of Vava’u and Ha’apai remained at Green (the first level on a four-level scale).

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.

Source: Tonga Geological Services, Government of Tonga