Explosive volcanic eruptions triggered by cosmic r

[geochem]

quote:

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Originally posted by peteadams

Yes, thank you Tom for your attention to facts.

OBob also misread the Washington Post regarding our lava composition. The article stated the island is constructed out of silica-poor basalt. The interesting aspect of Ormat drilling into the small (300' diameter X 50' thick) lava pool was that its composition was silica-rich, a glassy material, very different from our typical lava. According to the geologists, the silica-rich composition is more characteristic of continental rock than our usual island rock.

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As a possible point of interest: the silica-rich lava in the rift zone that Ormat encountered is the residual melt remaining after extensive crystallization of what was originally a basaltic intrusion. Kilauea likely won't be producing silica-rich magmas for another three-quarters of a million years...

[Hawaii Bound]

GeoChem, you said "...likely won't be producing silica-rich magmas for another three-quarters of a million years..." so your not 100% sure. It could happen sooner then?!?!

We are all going to die!!!!!!Run, everyone run.....

[geochem]

might be 600,000 years, but what's 150,000 years among friends....

[Opihikaobob]

Hi Geo , maybe you could further this thought for me . You said,

"Kilauea likely won't be producing silica-rich magmas for another three-quarters of a million years..."


But that doesnt necessarly mean their hasn't already been produced silica-rich magmas in other areas of Hawaii yet to be revealed ?

[geochem]

Not completely clear on your question - but Hawaii volcanoes do produce silica rich lavas, only not during the shield building phase of their life cycle (where Kilauea is now). The older volcanoes - like Mauna Kea and Hualalai have already produced silica rich lavas. Pu'u Wa'a Wa'a and Pu'u Anahulu were both produced by the same eruption that was silica rich: the lavas that form Pu'u Anahulu are trachytes and have a much higher silica content than the basalts that Kilauea is producing. The cinder cones on Mauna Kea are also silica rich - although I don't believe that the silica content there is as high as the Pu'u Anahulu lavas. However, silica rich lavas don't always erupt explosively - lots of other factors come into play to determine whether quiet effusion or a more violent explosive eruption occurs.

[terracore]

Here's some celestial phenomenon that may actually trigger eruptions:

http://hvo.wr.usgs.gov/volcanowatch/arch...05_28.html