A massive “raft” of volcanic rocks, known as pumice, is drifting through the Pacific Ocean, with its size being around 150 square kilometres, which is equivalent to the size of 20,000 football pitches.

According to various experts, the mass of pumice probably came from an eruption of an underwater volcano near Tonga, in the Southern Pacific Ocean. According to satellite images, the eruption occurred around 7 August.

Warnings have been issued to sailors to avoid the area in order to steer clear of any potential hazards.

Experts also added that large “rafts” of volcanic rock may form when the volcano is in shallow waters, with the rock often settling at the surface of the water.

The first to report the “pumice raft” was an Australian couple who were sailing their catamaran to Fiji when they encountered the massive amount of rubble during the night.

The couple wrote online that “The waves were knocked back to almost calm and the boat was slowed to one knot.” The rubble forced them to be temporarily stuck as the rocks left their rudder completely jammed. However, after some time they were able to navigate their way out of the field of pumice.

They also added that “The rubble slick went as far as we could see in the moonlight and with our spotlight.”

Ever since their venture in the Pacific, they have sent samples of the pumice stone to researchers at the Queensland University of Technology in Australia, ranging from marble to the size of a basketball.

Researchers say that such masses of volcanic rock are common every five years or so, with many people reporting that they are large islands “in the middle of the ocean that people encounter but then can’t find again”.

Such pumice has plenty of benefits, with it being a potential boost for reefs around the world.

With the volcanic rock being separated over time and drifting away in different currents, experts say that such pumice may become home to plenty of marine life.

Dr Martin Jutzeler from the University of Tasmania said that “A lot of life… can attach themselves to the pumice and be transported thousands of km away. So it’s a way to renew ecosystems somewhere, but it also can introduce invasive species.”

If it manages to reach the Great Barrier Reef in Australia, it might be of great benefit to the already very damaged reef, with coral regeneration collapsing in the world’s largest reef system after massive bleaching events in 2016 and 2017.