Our reigning champion Leslie has made a triumphant return this week after combing the virtual Earth (with a nit comb, probably) to find me at Suwanose-jima volcano in the Tokara Islands in the south of Japan.
The Tokara Islands are a volcanic archipelago that owe their existence to the Philippine Plate, which is subducting beneath the Eurasian Plate and keeps Suwanose-jima and her neighbors (including the more famous Sakura-jima) well supplied with rising magma.
Suwanose-jima island is populated by less than 50 people..most likely most of whom belong to a Japanese counter-culture commune that established itself there in the sixties. The volcano herself is one of the most active in Japan, and has a history of chasing people off her island. One such eruption in 1813-14 produced a subplinian column of ash, deposited tephra all over the island, created two distinct andesitic lava flows down her west flank and ultimately caused her east flank to collapse and formed the Sakuchi Caldera which extends to the island’s east The island’s settlements were abandoned and she had the island to herself for the next seventy years, which she appears to have spent being quiescent..except for one indulgent VEI 4 explosive eruption in 1877. Then in 1884-85 she welcomed the newly-returned humans to her island by sending a long lava flow toward the east coast.She has two summit craters, but most of her modern activity centers around the northeast O-take crater vent (sometimes called On-take or Ontake..not to be confused with Mount Ontake further north on Honshu).
She has remained active through the 20th and 21st centuries, including her most recent eruption, an ongoing affair that has lasted a little over eleven years. But a deeper look at the layers of tephra on the south of the island reveals a >23,000 year old 15 m thick ignimbrite overlying a 3 m thick layer of rhyolite pumice, giving reason to believe this volcano has had quite a violent past.
But she is an artist in her own way, as this exposed cliff of more recent layers of ejecta demonstrates.
Be sure to come back here on Monday evenings (NY-time) every week for a new volcano and new adventure. Also, my blog-anniversary and 50th Virtual Volcano Vacation challenge will be coming up in late December..and I am thinking up something to make that one extra special. I will have more to say about that in weeks to come.