Oceania | Environment | Oceania

Floating Volcanic Rock Is Disrupting Life in Papua New Guinea 

The ongoing Titan Ridge eruption has left parts of PNG’s coast covered in meters of floating volcanic rock. For a community dependent on the ocean, that’s a serious problem.

Pumice on the shore of Kunigami, Okinawa Prefecture, Japan, after the 2021 Fukutoku-Oka-no-Ba eruption.

People in parts of Papua New Guinea are facing an unusual problem. Floating volcanic rock is making boat travel difficult, blocking access to fishing grounds and disrupting daily life in coastal communities.

The source of the pumice is the ongoing Titan Ridge eruption from an underwater volcano in the Bismarck Sea. Since May 9, the eruption has produced vast amounts of pumice – a lightweight, porous volcanic rock that floats on the ocean surface.

Reports from Manus Province in the country’s northeast describe chunks of pumice accumulating along coastlines and waterways in enormous “rafts” 2–5 meters thick. In some locations, residents report being able to walk where there was previously open water.

It’s a strange sight, but not an unprecedented one. Submarine eruptions have produced similarly vast pumice rafts before, and the experience from those events suggests the disruption facing Manus communities could persist for months or even years, long after the Titan Ridge eruption itself has ended.

White plume and grey rafts of pumice spread from the Titan Ridge underwater volcano. Image by the European Space Agency.

For many Manus communities, small boats are essential for accessing fishing grounds, neighboring villages, markets, schools and healthcare services. When those transport routes become difficult to use, the consequences extend well beyond inconvenience.

PNG’s Disaster Minister Billy Joseph has described growing concerns regarding food security and access to essential supplies.

The ocean serves as the backbone of Manus livelihoods, providing daily sustenance and the primary source of income through seafood sales. In some villages, residents have begun manually clearing pumice from shorelines and waterways in an effort to restore access to fishing grounds and prevent longer-term damage to local fisheries.

Titan Ridge is not the first submarine eruption to generate widespread pumice rafts. In 2021, the submarine eruption of Fukutoku-Oka-no-Ba south of Japan produced large quantities of floating pumice that drifted to the Nansei islands including Okinawa. There, pumice clogged 71 harbors and marinas, damaged hundreds of vessel engines, disrupted ferry services, and affected tourism and fishery industries. The economic cost in the Okinawa Prefecture alone exceeded 515 million yen.

Japan had extensive transport infrastructure, alternative supply chains and substantial federal resources for clean-up and recovery. The cleanup effort employed heavy machinery on land and sea and removed more than 110,000 cubic metres of pumice from the ports and beaches at an additional cost of more than 1 billion yen.

Despite its scale, the cleanup was only somewhat useful. Most pumice rafts only washed away the following spring with the change in seasonal winds.

While pumice from........

© The Diplomat