Sunday, December 6, 2015

New Island Nishinoshima

This week I learned of a volcanic island about a thousand kilometers south of Tokyo named Nishinoshima (“western island” in Japanese). Prior to 1973, Nishinoshima was a tiny islet comprising the northwest ridge of an underwater caldera about a kilometer across and about a hundred meters beneath the ocean surface at its deepest.  No eruptions at this volcano had ever been recorded in the historical record.

Starting in May 1973, however, the volcano began erupting, ultimately forming a new island to the east of the old one. The volcano fell silent a bit less than a year later, after which wave action joined the new and old islands (the new one being composed of a lot of cinder doubtless helped).

There things rested until November 2013 when the volcano began erupting again, creating another new islet off the southeast coast of the old one. This eruption continued vigorously until it had created an island larger than the one already existing. The Japanese government (which claims the island[s]) was reportedly waiting for the eruption to stop to give the new island a name, but this was rendered moot soon thereafter when the still-growing island connected to the old one, making a single island a bit over two square kilometers.

The eruption continues to this day (as far as I can tell), though it's become a lot less vigorous and may be dying down. Here's what the island looks like on Google Maps at the moment: the older part of the island is the north-western part in the lighter tan color (it's clearly recognizable in an image from December 8, 2013).

I thought it was a neat look at what the Hawaiian islands must have looked like at one point, breaching the surface of the ocean and building up to the towering edifices they became. The base Nishinoshima volcano already rises nearly three kilometers from the ocean floor and is nearly thirty kilometers across at its base, so it could presumably get a lot taller. All very interesting. A hui hou!

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