Friday, May 4, 2012

Japan's Iwo Jima (Ioto) Volcano Showing Signs of Activity

A report from Japan's Meteorological Agency indicates new activity at the famed WWII island of Iwo-Jima (Ioto). The report details that a new fumerole has opened, and there was water discoloration in the water near the island. Famed for its role in WWII when US forces were striking at Japan, most people don't realize it is actually an active volcano! While Iwo-Jima didn't have explosions during the war (without the aid of bombs and artillery), the island constantly fumes with acidic pools, fumeroles, and is prone to frequent, and small, phreatic eruptions.

The Smithsonian GVP characterizes Iwo-Jima here:

"Ioto (also known as Iwo-jima) in the central Volcano Islands portion of the Izu-Marianas arc lies within a 9-km-wide submarine caldera. Ioto, Iwo-jima, and Io-jima are among many transliterations of the name, which means "Sulfur Island;" the volcano is also known as Ogasawara Io-jima to distinguish it from several other "Sulfur Island" volcanoes in Japan. The triangular, low-elevation, 8-km-long island narrows toward its SW tip and has produced trachyandesitic and trachytic rocks that are more alkalic than those of other Izu-Marianas arc volcanoes. The island has undergone dramatic uplift for at least the past 700 years accompanying resurgent doming of the caldera. A shoreline landed upon by Captain Cook's surveying crew in 1779 is now 40 m above sea level. The Moto-yama plateau on the NE half of the island consists of submarine tuffs overlain by coral deposits and forms the island's high point. Many fumaroles are oriented along a NE-SW zone cutting through Moto-yama. Numerous historical phreatic eruptions, many from vents on the west and NW sides of the island, have accompanied the remarkable uplift."

The island rises from the seafloor to the surface due to the Pacific and Asian plate subduction zone, very close to the Marianas Trench, the deepest chasm on earth, where famed film director James Cameron just set a new depth record for an upcoming documentary on the trench. The Marianas Trench is a result of severe collision and subduction of the two plates and is prone to frequent submarine, and island volcanism, as well as very powerful earhquakes ranging up to 8.6 in magnitude (as far as we know). This is South of the fault that caused the devastating 9.0 earthquake in Japan last year which resulted in a large tsunami, and damaged the nuclear power plant at Fukushima.

Other volcanoes currently erupting in Japan include Sakura-jima, Kirishimayama (Shinmoedake), Miyake-jima, Suwanose-jima, Satsuma-Iojima, and Fukutoku-Oka-no-ba.

Japan, much like Indonesia, Russian Kamchatka, The West Coast of the USA, and the entire coast of South America, is part of the so-called Pacific Ring of Fire, and is quite prone to earthquakes and frequent volcanic eruptions. Most eruptions are fairly benign, and Japan has a large appetite for geothermal energy, and volcanic hot springs which the locals consider great medicine for skin ailments, and skin health. Locals love to use the hot water, and fine ash for exfoliation, and relaxation, and the volcanic resort towns are world renowned for their innovative use of what most people consider to be a dangerous and destructive force... but when your culture is as old as some of the volcanoes themselves... well, you either adapt or you don't!

A follow up also on the purported activity at Japan's Mt Fuji, which I touched on a while back. NO new info, video, photos, or anything of the sort has confirmed the news report from Japan about a "row of new craters" on the eastern flank, and recent satellite photography did not reveal these features on the mountain. I suspect that someone was rather mistaken, and wished to hype up the possibility of the eruption. In my previous blog post on Mt. Fuji, I pointed out that I was highly skeptical of the possibility of eruption, due to Fuji's worldwide fame, and the swiftness at which social media can cover such an event. Fuji is not an inconspicuous volcano, and I assume if there was ANY activity, it would be huge news quite fast.

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