Iwo-jima volcano (Volcano Islands, Japan): northern arm of island extends as eruptions continue

Phreatomagmatic explosions from the new volcanic islands (image: NHK)

The explosive eruption at the new volcanic island resumes.
Minor surtseyan explosions continue to take place at the eruption site and gradually shape the island. The newly formed island has been growing as ejected tephra, mainly comprised of dark black masses of lava bombs and previously lava flows, enlarges the area island by piling lava material mostly to the north side. However, the morphology of the island undergoes strong ocean wave erosion as the edifice solely consists of loose, juvenile lava material so far, meaning it is highly prone to collapse into water. Phreatomagmatic activity (also known as surtseyan) means that erupting magma reacts with external water, e.g. ground water, lake water, sea water etc.

In the attached animation, the J-shaped island, consisting of one northwesterly and another elongated northerly facing arm, of which the right one (north), 513 meters long stretched „branch“, has extended further north direction between 27 November and 2 December. By 2 December, the north arm tip was about 157 meters offshore from Iwo-jima island.

The strong degassing of volcanic emissions accompanies the activity.

The new volcanic island formed off the south coast of the Iwo-jima island (image: Sentinel-2)