Volcano Erupts in Japan; Injuries Reported

[jakeXT]

A volcano erupted in central Japan on Saturday, catching mountain climbers by surprise and seriously injuring at least one person.

With a sound likened to thunder, Mt. Ontake spewed large white plumes high into the sky, sending people fleeing and covering surrounding areas in ash.

Several people were injured, including one who was unconscious, according to Japanese media reports.

The 3,067-meter (10,062-foot) peak erupted shortly before noon on a bright sunny autumn morning. In a YouTube video shown on Japanese TV, surprised climbers can be seen moving quickly away from the peak as an expanding plume emerges above and then engulfs them.

One witness, talking to Japanese broadcaster NHK, said the eruption started with large booms like thunder. It also reported that people had been evacuated from a mountain lodge.

http://abcnews.go.com/International/wireStory/volcano-erupts-japan-injuries-reported-25798746

[SamKnause]

1. The first video has been blocked.

[jakeXT]

2. I replaced it with a NHK one, but it's not the full clip /nt

[SamKnause]

3. Thank you.

[NCcoast]

4. There sure do seem to be a lot of volcanoes erupting these days

How far fetched is it to think that fracking might be contributing to this? When you have earthquakes taking place in Oklahoma, could it be that we are screwing the balance of the earth's crust and contributing to increased volcanic activity?

[Old Crow]

5. I'm no scientist, but...

... I'd have to say it's unlikely there's any connection to fracking. The Earth's crust is divided up into separate tectonic plates, which are unconnected (although, of course, they do press, rub, dive beneath, and slide atop of each other, occasionally producing earthquakes). In addition, the activities of fracking, while they might generate small tremors in a small area, are insignificant compared with the convection currents of trillions and trillions of tons of hot magma circulating in the Earth's mantle.

If anyone has more information or ideas, supporting or refuting the above, I'd love to hear them. I don't know that much and would like to learn more. Thanks.

[jakeXT]

7. Here are 48 great lectures (about 24h of video)

http://www.infocobuild.com/education/learn-through-videos/earth-science/how-the-earth-works.html


Water plays a role in subduction zone volcanoes, but yes the quantity is bigger and it occurs deeper than during fracking.

Where two tectonic plates converge, if one or both of the plates is oceanic lithosphere, a subduction zone will form. An oceanic plate will sink back into the mantle. Remember, oceanic plates are formed from mantle material at midocean ridges. Young oceanic lithosphere is hot and buoyant (low density) when it forms at a midocean ridge. But as it spreads away from the ridge and cools and contracts (becomse denser) it is able to sink into the hotter underlying mantle. There is a deep ocean trench where the oceanic plate bends downward.

Volcanic Arcs: The basaltic ocean crust contains hydrous minerals like amphiboles, some of which formed by hydrothermal alteration as seawater seeped through hot, fractured, young ocean crust at the midocean ridge. As the ocean crust sinks deeper into the mantle the pressure increases (the temperature of the ocean crust rocks increases more slowly because rocks are poor conductors of heat). At depths of around 100 km beneath the surface, the pressure is great enough for the hydrous minerals to undergo metamorphism. The resulting minerals are denser and they don't contain the bonded water. This metamorphic dewatering process liberates water from the descending crust. The water gradually seeps upward into the overlying wedge of hot mantle. The addition of water to the already hot mantle rocks lowers their melting temperature resulting in partial melting of ultramafic mantle rocks to yield mafic magma. Melting aided by the addition of water or other fluid is called flux melting. It is somewhat more complicated than this, but metamorphic dewatering of suducting crust and flux melting of the mantle wedge appears to account for most of the magma at subduction zones.

Magma formed above a subducting plate slowly rise into the overriding crust and finally to the surface forming a volcanic arc, a chain of active volcanoes which parallels the deep ocean trench. Beneath the active volcanic arc lie intrusive igneous rocks formed from magma that didn't make it all the way to the surface before crystallizing. The volcanic arcs may be volcanic island arcs (e.g., Aleutians, Mariannas), where one oceanic plate subducts beneath another oceanic plate, or continental volcanic arcs (e.g., Andes, Cascades), where oceanic plates subduct under a continental plate. The most abundant igneous rock formed at volcanic arcs is andesite (or intrusive diorite), though volcanic arc rocks may range in composition from basalt to rhyolite (mafic to felsic).



http://www.columbia.edu/~vjd1/subd_zone_basic.htm

[Brother Buzz]

6. Not necessarily more volcanoes erupting...

just better, faster communication