Huge amounts of pumice washed ashore on Okinawa could affect Japan’s nuclear power plants

Large amounts of pumice from a massive underwater volcanic eruption washed ashore on the main island of Okinawa Prefecture and elsewhere this week, affecting the fishing industry and ship operations.

A pumice release has also been reported in the Amami area of Kagoshima Prefecture. On Oct. 27, a Nuclear Regulatory Authority official urged officials to prepare because the pumice could affect the intake of water used to cool nuclear reactors.

The source of the pumice is the underwater eruption of the Fukutoku-Okano-Ba volcano in the Ogasawara chain of islands in August 2021, one of the largest of any land and sea eruption in Japan since 1945. The estimated volume of pumice and ash ejected was at least 100 million cubic meters.

According to the prefectural government, pumice began to wash ash on Kita Daitojima in early October, and this was confirmed throughout the island of Okinawa.

The government reported that about 10 tons of pumice was removed daily at the Henton fishing port in Kunigami Village, but the rocks continued to wash ashore at the port seemingly indefinitely.

The report said that about 750 fishing boats could not leave the port because of concerns about engine problems.

Toru Miyama, a senior ocean physics scientist at the Japan Agency for Marine Science and Technology, estimated that the pumice ejected by the volcano was swept away mostly by the western countercurrent of the Kuroshio and washed ashore in Okinawa Prefecture.

Some of the rocks could then be carried northward by the Kuroshio Current and approach the Pacific region of Shikoku in early November and Shizuoka and Chiba prefectures by the end of November.

At a regular meeting on October 27, Ishiwatari Akira, a member of the Nuclear Regulatory Authority, said that the pumice could affect the intake of water used to cool nuclear reactors.

Ishiwatari urged officials to prepare because the rocks are likely to arrive on Japan’s main island of Honshu.

Nuclear Regulatory Authority officials said that one effective way to get rid of the pumice is through measures taken at each plant to remove jellyfish in case of a plague. They also say that installing fencing in front of water intake equipment could work.

Pumice Source.

A major eruption began at Japan’s Fukutoku-Oka no Ba underwater volcano at about 21:20 UTC on August 12, 2021, and continued through August 13.

According to the Tokyo VAAC, at 23:50 UTC, volcanic ash rose up to 16.4 km (54,000 ft) above sea level and headed southwest toward the Philippines.

Notify of

Inline Feedbacks
View all comments
Would love your thoughts, please comment.x