Efforts have begun to manufacture concrete blocks using a large amount of pumice stones washed ashore by the eruption of a submarine volcano in the Ogasawara Islands.
In August, a large amount of pumice erupted from a submarine volcano in the Ogasawara Islands arrived in Okinawa Prefecture and elsewhere.
In an attempt to utilize these pumice stones, a concrete manufacturing company headquartered in Seki City, Gifu Prefecture, began an initiative to manufacture concrete blocks using pumice stones washed ashore in the port of Yonabaru Town, Okinawa Prefecture in December last year.
It means that a mobile concrete mixer is brought near the port of Yonabaru Town, and the collected pumice stones are used as an alternative material to gravel, using a unique technology that mixes with cement.
Pumice stones are piled up in the local port, and the company is proposing to Okinawa Prefecture whether it can be used as a fish reef by submerging concrete blocks in the sea, together with a local fishery cooperative.
As of last month, the pumice stones that were washed ashore and recovered amounted to about 20,000 cubic meters in Okinawa Prefecture alone, and are attracting attention as a new treatment method for pumice stones.
Munenori Yamashita, managing director of a concrete manufacturing company, said, "The advantage is that concrete can be manufactured on the spot, and returning it to the sea as a fish reef will lead to effective utilization."