The new island was discovered about 50 km (31 mi) south of Iwo Jima, Ogasawara Island, Japan, just three days after the massive underwater eruption of the Fukutoku-Oka-no-Ba volcano.
According to the Japan Meteorological Agency (JMA), the new island is about 1 km (0.62 mi) in diameter and is C-shaped. It was discovered on Sunday 15 August.
In addition, pumice from the eruption was found on the coast, floating 60 km (37 mi) northwest of the island.
New islands were discovered in the area in 1904, 1914 and 1986, all of which went under water, Kyodo reports. Discovered in 1986, the island sank after about two months, according to the Coast Guard.
A major eruption began at Fukutoku Oka no Ba at approximately 21:20 UTC on August 12, 2021 and continued until August 13.
According to the Tokyo VAAC, volcanic ash rose to 16.4 km (54,000 feet) above sea level at 11:50 UTC and was heading southwest towards the Philippines.
The Japanese Coast Guard said the eruption was "so massive that it was impossible to observe it in the immediate vicinity," and called for caution in ships and aircraft in the vicinity.