Floating pumice disaster requires flexible action with focus on ports

A massive amount of floating pumice has drifted to the main island of Okinawa Prefecture and remote islands in Kagoshima Prefecture, severely affecting the local fishing and tourist industries. There are concerns the floating stones will make it to Honshu and other areas. The central government needs to make every possible effort to remove them as soon as possible.

The pumice was produced by the eruption of an undersea volcano off the Ogasawara Islands in August this year. It is believed that it took about two months for the mass to ride the current and reach the Okinawa coastline and other areas.

The volcano also erupted in 1986, and a small amount of pumice washed ashore in Okinawa. This time, however, the eruption was on a far larger scale, and was so massive that the stones seem to blanket the ports and beaches. It can be said that this is a new form of volcanic disaster.

In Okinawa Prefecture, where the drifting cluster was reported, fish in breeding pens died and fishing boats were unable to ply their trade. Some ferries had to suspend operations because the vessels’ engines became clogged with pumice when taking in cooling water. In addition, it is feared this will have a negative effect on tourism.

A situation that hinders both the daily lives of local residents and the flow of trade must be avoided.

The Okinawa prefectural government is using heavy machinery to scoop up stones that have accumulated in ports and harbors for disposal elsewhere. The central government said it will provide financial support via a subsidy system in place for disaster recovery and other projects. In addition to funding, it should take the initiative by supplying materials and dispatching experts.

There is fear that the pumice will make it to Kyushu, Shikoku and Honshu by riding the Kuroshio current. Drifting debris believed to be pumice has already been confirmed off the coast of Kochi Prefecture. Those involved in the shipping industry, and nuclear power plants that take in cooling water, among others, must make efforts to collect information in preparation for the arrival of the drifting stones.

Although pumice is troublesome when it comes in large quantities, individual pieces are brittle and highly likely to be pulverized by waves and winds over the long term. When crushed into small grains, it loses its buoyancy and can be expected to sink to the seafloor.

For this reason, instead of taking time to completely clear beaches of the pumice, the aim should be to prioritize key locations for quick extraction such as ports and harbors that support fisheries and trade distribution.

Natural disasters very often force people to dispose of large amounts of waste resulting from the calamity. When a major earthquake, flood or mudslide hits, it is not uncommon for waste disposal to become problematic because such a large amount is generated, such as from collapsed or flooded houses.

It is important for local governments to consider establishing temporary storage and disposal sites in advance so that they are able to deal with situations like the drifting pumice.

The Japanese archipelago has a series of volcanoes and many earthquakes. In recent years, damage from heavy rains has also occurred frequently. This time, a situation has arisen that could not have been forecast. But being constantly prepared for a wide range of natural disasters will enhance our ability to cope with unforeseen circumstances.

— The original Japanese article appeared in The Yomiuri Shimbun on Nov. 4, 2021.