Tokyo VAAC reported volcanic ash from Nishinoshima at 3 km (10,000 ft) a.s.l. at 2203 on 30 June; the plume extended NE. However, ash was not visible in satellite images. The University of Hawaii reported that Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data detected thermal anomalies and issued MODVOLC alerts during 25 June-13 July with the exceptions of 8, 11, and 12 July.

Geological Summary. The small island of Nishinoshima was enlarged when several new islands coalesced during an eruption in 1973-74. Multiple eruptions that began in 2013 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.

Sources: Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts Team, Tokyo Volcanic Ash Advisory Center (VAAC)