Report on Nishinoshima (Japan) — 20 November-26 November 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 20 November-26 November 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on Nishinoshima (Japan). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 20 November-26 November 2013. Smithsonian Institution and US Geological Survey.
27.247°N, 140.874°E; summit elev. 25 m
All times are local (unless otherwise noted)
The Japanese Coast Guard reported that a Surtseyan eruption 500 m SE from the coast of Nishimo-shima generated a new island called Niijima on 20 November. The island was about 300 x 200 m, and developed a crater 150m wide. Discolored water surrounded the island. Based on satellite images, as well as accounts from the Japanese Coast Guard and JMA, the Tokyo VAAC reported that a plume rose 600 m. On 22 November the eruption continued and incandescence within the crater was observed. An ash plume rose 900 m and drifted SE. On 24 November lava flows from the crater extended to the coastline of the island, and bombs continued to be ejected.
Geologic Background. 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.