Researchers in Japan say a large quantity of pumice stones from an underwater volcanic eruption in the Pacific could soon arrive in waters south of Tokyo.
The Japan Agency for Marine-Earth Science and Technology, or JAMSTEC, on Tuesday released its latest simulation.
It suggests that the stones will likely drift northward off the coast of eastern Japan, but that a large amount could reach Tokyo's remote Izu Islands as early as Friday.
The simulation also suggests that some of the pumice around the southwestern prefecture of Okinawa will stay for some time, depending on the winds.
Last month, pumice stones were first sighted in the southwestern region after the eruption of the undersea volcano in August. Ferry services, fishing operations and tourism have been affected.
Since last week, small amounts of pumice stone have been found in waters around some of the Izu Islands, as well as in Chiba Prefecture neighboring Tokyo.
JAMSTEC senior researcher Miyama Toru warned that a large quantity of stones could keep washing ashore on the Izu Islands, just as in Okinawa, after initial smaller amounts of stone appear.
He added that if observers spot pumice stones, it is important to swiftly share information so that measures can be taken at ports and other places.