JMA reported that the eruption at Nishinoshima had been particularly vigorous since mid-June, producing a large amount of ash. Based on satellite data, the Tokyo VAAC reported that during 1-3 and 5-7 July ash plumes rose to 2.7-4.9 km (9,000-16,000 ft) a.s.l. and drifted N and NW, and sometimes SW. On 4 July, ash plumes rose to 8.3 km above the summit (or to 24,000-28,000 ft. a.s.l.), the highest recorded plume since the volcano became active in 2013.

Sources: Japan Meteorological Agency (JMA), Tokyo Volcanic Ash Advisory Center (VAAC)

Geological Summary. The small island of Nishinoshima was enlarged when several new islands coalesced during an eruption in 1973-74. Multiple eruptions between 2013 and 2023 completely covered the previous exposed surface and continued to enlarge the island. The island is the summit of a massive submarine volcano that has prominent peaks to the S, W, and NE. The summit of the southern cone rises to within 214 m of the ocean surface 9 km SSE.