The Tonga Geological Services reported that daily steam plumes from Home Reef were identified in satellite images during 4-11 October. The Aviation Color Code was raised to Orange (the second highest level on a four-color scale) on 5 October. At 0040 on 6 October an ash plume rose as high as 3 km (10,000 ft) a.s.l. and drifted 5 km SE. Satellite-based measurements showed that the island had not changed in size between 28 September and 10 October, remaining at 268 m N-S and 283 m E-W. The island reached 15-18 m above the water surface, and was steeper on the E half but more gently sloped on the W. The daily emission count variable with about 8-19 events per day during 4-9 October and about 1-3 per day during 10-11 October. The Aviation Color Code was lowered to Yellow on 11 October. Mariners were advised to stay 4 km away from the volcano.

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, copious amounts of floating pumice, and an ephemeral island 500 x 1500 m wide, with cliffs 30-50 m high that enclosed a water-filled crater. Another island-forming eruption in 2006 produced widespread dacitic pumice rafts that reached as far as Australia.

Source: Tonga Geological Services, Government of Tonga