Steam is continuously emitted from the vent of Home Reef volcano, indicating that volcanic activities are still ongoing at the reef, which has grown in size by up to 8 acres between June 15-30 as a result of lava flows, Tonga Geological Services reported today.

Satellite imaging from MODIS-MIROVA shows that in the past 48 hours the thermal anomalies remain at very low to low levels. (Figure 1), TGS stated on 2 July.

The monitoring of the volcano by TGS is ongoing daily on the status of the current eruption.

Home reef island increasing

“Figures 2 & 3 are showing the growth of the island from images captured on 15 June (Figure 2) and 30 June (Figure 3).

"The effusive eruption of the volcano continues, resulting in the flowing of lava to the east of the island, hence increasing its size."

“From 15 June to 30 June, the area of the island increased from 22 acres to 29 acres,” TGS stated.

Meanwhile, the volcanic activity poses a low risk to the Vava’u and Ha’apai Communities.

"All Mariners are advised to sail beyond 4 km from Home Reef until further notice."

TGS advised the public to adhere to these restrictions for safety purposes.

Home Reef is located 25 km southwest of Late Island, 22 km northeast of Lateiki, and 75 km northwest of Mo’unga’one Island, at Latitude & Longitude 18.992°S & 174.775°W.

Submarine volcano

The Global Volcanism Program [2] of the Smithsonian Institution describes Home Reef as a submarine volcano located in the central Tonga islands between Lateiki (Metis Shoal) and Late Island. The first recorded eruption occurred in the mid-19^th century, when an ephemeral island formed. An eruption in 1984 produced a 12-km-high eruption plume, a large volume of floating pumice, and an ephemeral island 500 x 1,500 m wide, with cliffs 30-50 m high that enclosed a water-filled crater. Another island-forming eruption in 2006 produced widespread pumice rafts that drifted as far as Australia; by 2008 the island had eroded below sea level. The previous eruption occurred during October 2022 and was characterized by a new island-forming eruption, lava effusion, ash plumes, discoloured water, and gas-and-steam plumes Discoloured water plumes during November 2022 through April 2023 were observed using satellite data.

The Tonga Geological Services reported that an eruption at Home Reef was ongoing during 18-25 June [and continuing]. Daily thermal anomalies were identified in satellite images, though the number and intensity of the anomalies were variable. At around 0130 on 21 June an ash-and-gas plume was identified in satellite images drifting SE. Lava continued to expand the SE coastline of the island.

The Maritime Alert Level remained at Orange (the second highest level on a four-colour scale) and mariners were advised to stay 4 km away from the island, the Aviation Colour Code remained at Yellow (the second lowest colour on a four-colour scale), and the Alert level for residents of Vava’u and Ha’apai remained at Green (the lowest colour on a four-colour scale).