Regarding the eruption that occurred in August at Fukutoku-Okanoba, a submarine volcano in the Ogasawara Islands, a group of experts analyzed the amount of magma that erupted, and it was the largest volcanic eruption in Japan since the Meiji era. I announced the research result.
A large amount of pumice stones erupted at this time were washed ashore in Amami, Okinawa, but experts point out that it may continue in the future.
Fukutoku-Okanoba, a submarine volcano south of Iwo Jima in the Ogasawara Islands, experienced a large-scale eruption on August 13, creating two islands due to a large amount of ejecta.
Research groups such as the Industrial Technology Research Institute analyzed the eruption scale based on observations from the meteorological satellite "Himawari" and father islands about 300 km away, and found that the height of the eruption was 16,000 meters to 10,000 meters. It reaches 9000 meters and the amount of magma eruption is estimated to be about 300 million to 1 billion tons.
For this reason, the research group said that the scale of this eruption was the second largest volcanic eruption in Japan since the Meiji era, following the "Taisho eruption" that occurred in Sakurajima in 1914 (Taisho 3). is.
A large amount of pumice stones washed ashore one after another in Okinawa and Amami
On the other hand, a large amount of pumice stones generated by the eruption moved to the west due to the influence of ocean currents, and after the beginning of October, about two months after the eruption, they were washed ashore one after another in the Amami region of Okinawa and Kagoshima prefectures. I'm having trouble navigating.
When the research team investigated on the main island of Okinawa, it was found that pumice stones were piled up thickly on the coast, and some of them were 25 cm long.
As of October 15, a large amount of pumice stones have been confirmed about 50 km off the main island of Okinawa, so it is expected that they will continue to be washed ashore for some time.
Teruki Oikawa, a senior researcher at the National Institute of Advanced Industrial Science and Technology, said, "The fact that this amount of pumice was washed ashore on the coast shows that it was a very large-scale eruption. In addition to power plants and steelworks that use seawater. , I want people who operate fishing boats and ferries to be careful. "