Report on Nishinoshima (Japan) — 29 July-4 August 2020
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
29 July-4 August 2020
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2020. Report on Nishinoshima (Japan). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 29 July-4 August 2020. Smithsonian Institution and US Geological Survey.
27.247°N, 140.874°E; summit elev. 25 m
All times are local (unless otherwise noted)
Based on satellite data, the Tokyo VAAC reported that during 29 July-3 August ash plumes from Nishinoshima rose to 3.4-5.8 km (11,000-19,000 ft) a.s.l. and drifted in multiple directions. Strong sulfur dioxide signatures continued to be detected in satellite data.
Geological Summary. The small island of Nishinoshima was enlarged when several new islands coalesced during an eruption in 1973-74. Another eruption that began offshore in 2013 completely covered the previous exposed surface and enlarged the island again. Water discoloration has been observed on several occasions since. The island is the summit of a massive submarine volcano that has prominent satellitic peaks to the S, W, and NE. The summit of the southern cone rises to within 214 m of the sea surface 9 km SSE.