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Japan: Kurikoma activity raises questions 17 June 2008

Posted by admin in activity reports, blogs, geoscience, Japan, Kurikoma.
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Hot gas plumes thought to consist of volcanic gases have been detected 7km south-west of the summit of Mt Kurikoma, a 1628m stratovolcano in northern Honshu (see Erik’s Eruptions blog for more). Kurikoma last erupted in 1950, and has in general a rather sketchy eruptive history.

The volcano is in the area affected by Friday’s 6.8M earthquake, so are these phenomena related? Here’s what the Japanese press report says:

Associate Prof. Sadato Ueki of Tohoku University’s Research Center for the Prediction of Earthquakes and Volcanic Eruptions said the plumes might be volcanic gases rising to the Earth’s surface.

‘There’s a possibility that volcanic gases that had been confined below ground are gushing out through fissures in the mountain created by the earthquake,’ he said.

Ueki said it was also possible that the plumes were steam coming from underground hot water channels that had their course diverted by the earthquake.

But the professor ruled out the possibility of increased volcanic activity on Mt. Kurikoma, saying that the plumes were very far from the summit of the volcano.

So the professor is suggesting the plumes might be by-products of the earthquake. Kim at All of My Faults Are Stress-Related similarly asks ‘Did the earthquake … cause Kurikoma to start acting up?’, but also observes that this was a rather unusual earthquake. It was along a thrust fault, but it was in Honshu’s volcanic arc, which is not where you would expect a thrust earthquake to be. Kim asks whether the quake itself might be the result of local magmatism: ‘the fault mechanism isn’t surprising. But the location is. Is this a case where the magmatism created a weaker zone in the crust and allowed thrust faulting to take place?’

It will be interesting to watch what happens.

Information
Global Volcanism Program: Kurikoma – summary information for Kurikoma (0803-21=)

News
Hot gas plumes detected at Mt. KurikomaDaily Yomiuri Online, 17 June 2008

The Volcanism Blog