In 1984, Tonga's Home Reef shot a 12km-high plume into the sky and built an island. 42 years later, the growing volcanic island has gained nearly 20 acres of land

In 1984, Tonga's Home Reef shot a 12km-high plume into the sky and built an island. 42 years later, the growing volcanic island has gained nearly 20 acres of land. The underwater volcano has been changing the shape of the seafloor and the surface of the South Pacific through repeated eruptions. Home Reef is a submarine volcano located on the Tonga Volcanic Arc, west of the Tonga Trench in the South Pacific. The area is part of one of the most active volcanic arcs on Earth. Eruptions at Home Reef can push volcanic material above the ocean and create islands. These islands can later be reduced or removed by erosion.

Home Reef has created and lost islands for more than a century

The first recorded eruption of Home Reef took place in 1852. Another eruption followed in 1857. Since then, the volcano has gone through periods of activity and inactivity. NASA Science says cycles of eruptions and erosion have created and destroyed a small island at the location since at least the middle of the 19th century.


These islands are known as ephemeral islands. They can appear after an eruption and remain above the ocean for some time before waves and other processes reduce their size. Home Reef remained seemingly quiet for more than 100 years after its earlier activity. That changed in 1984, when the submarine volcano produced a major eruption.

The 1984 eruption created an island

The 1984 eruption produced a plume that reached 12 kilometres into the sky. It also released a large amount of floating pumice. The eruption created an island measuring about 500 by 1,500 metres. The island had cliffs between 30 and 50 metres high. A water-filled crater was enclosed within the newly formed land.

The eruption showed how quickly an underwater volcano can change the surface of the ocean. Material released from the volcano accumulated above sea level and formed land. The island did not mark the end of Home Reef's activity. The volcano became active again more than 20 years later.

The 2006 eruption sent pumice toward Australia

In 2006, another eruption at Home Reef created an island. The event also produced widespread pumice rafts. The Global Volcanism Program records that these floating pumice rafts travelled as far as Australia.

Pumice forms when volcanic material cools after being expelled during an eruption. Because it can contain trapped gas and remain less dense than water, large amounts of pumice can float across the ocean. The 2006 event again showed that an eruption at a remote submarine volcano can produce effects that travel far from the eruption site.

Activity returned in 2022

Another period of volcanic activity started in 2022 and has continued through subsequent years. In September 2022, Home Reef erupted six times within 24 hours. The activity produced ash that entered the atmosphere. Pilots were warned to take care when flying through the area because of the ash. Sailors were also advised to remain at least 4 kilometres away from the volcano.

The warnings reflected the changing conditions around an active submarine volcano. Ash in the atmosphere can create a hazard for aircraft, while volcanic activity and floating material can create risks for vessels.

A 2025 eruption sent ash 12km high

Home Reef remained active in the following years. In June 2025, an eruption sent ash up to 12 kilometres into the atmosphere. The continued activity also changed the size and shape of the island.

NASA Science reports that lava flows beginning in December 2025 first extended the island toward the east and south. The flows later moved the island's footprint toward the northwest and then toward the north. This process added new land to the island.

A volcanic gas plume also remained part of the eruption period. NASA Science says plumes of volcanic gases rose from a vent measuring about 100 metres in diameter throughout the eruptive period.

The island gained nearly 20 acres by February 2026

The lava flows continued to change the footprint of Home Reef. By February 2026, the island had expanded by nearly 20 acres. The growth shows how repeated volcanic activity can add land to a temporary volcanic island. However, the island's future size is not fixed.

Home Reef has a history of island creation followed by erosion. Waves and other forces can remove volcanic material after an eruption stops or becomes less active. This means the land created by the recent eruptions could also change over time.

Satellites help scientists monitor the remote volcano

Home Reef is located in an area that is difficult for scientists to access directly. Satellites therefore play an important role in tracking the volcano. NASA Science says satellites are important for monitoring volcanoes in remote locations that are difficult to reach.

Satellite observations can show changes in the island's shape and size. They can also help identify volcanic activity and changes in the surrounding ocean. Scientists and monitoring agencies use satellite data along with other sensors to follow activity at Home Reef. One feature visible in some satellite images is discoloured water around the volcano during periods of activity.

Why does the water around Home Reef sometimes change colour?

The discoloured water can be linked to volcanic gases and fluids entering the ocean. These materials mix with seawater and can include sulphur. NASA Science notes that the presence of sulphur can give the water a green appearance.

The water can contain material released from the underwater volcanic system. Previous research has found that plumes of superheated and acidic water can contain particulate matter, fragments of volcanic rock and sulphur.

These underwater plumes can sometimes appear before an eruption becomes visible above the ocean surface. This gives scientists another feature that can be monitored when studying volcanic activity.

What does Home Reef mean for marine life?

The current activity at Home Reef is not thought to pose a risk to nearby inhabited islands. However, the volcano can affect life in the surrounding ocean. The effects can be harmful in some situations. NOAA oceanographer Sharon Walker has said that hot and acidic plumes released into the ocean can harm marine organisms and can also kill them.

A previous example occurred after an underwater volcano called Nafanua, near American Samoa, erupted. Dead animals were found across the floor of its crater. The conditions created by volcanic activity can therefore affect marine ecosystems around an eruption site.

Volcanic activity can also create new habitats

The effects of an underwater volcano are not limited to damage. Volcanic jets of water can contain elements such as iron. These elements can support plankton growth. Plankton form an important part of marine food systems, so changes in their growth can affect other organisms in the surrounding environment.

The creation of new land can also provide habitat. When volcanic islands emerge above the ocean, they can offer surfaces where algae can grow. Insects and birds can also use newly formed land. As vegetation and organisms establish themselves, the new island can become part of the surrounding ecosystem. Home Reef therefore provides an example of how volcanic activity can repeatedly alter both land and ocean environments.

What happens next at Home Reef?

Home Reef remains a changing volcanic system. Its history includes eruptions, island formation, erosion and renewed volcanic activity. The island's recent expansion resulted from lava flows that moved across its surface and increased its footprint. Satellite monitoring will allow scientists to continue tracking those changes.

The nearly 20 acres added by February 2026 are part of the volcano's latest period of island growth. The long-term size of the island will depend on future eruptions and erosion. For scientists, Home Reef also provides an opportunity to study how submarine volcanoes build land, alter seawater and affect ecosystems.