When XtnYoda was just a lad he was taught in our classrooms that our planet was a dying planet and one evidence was what was called "Extinct" volcanoes. After the "rebirth" of formerly extinct volcanoes such as Mt. St. Helens, the term "extinct" was dropped and replaced with the term "Dormant Volcanoes". The planet earth is still very much a dynamic planet, and from the appearance of the dramatic increase in earthquakes and "un-extinct....formerly extinct" volcanoes we see that our planet still has the ability to affect itself...and that without our help.
How outdated is much of our thinking about under-ocean volcanic activity? Consider this article from October 16, 2005 where a University of Hawaii professor speculates that our former thinking may have been wrong about how long it takes for "under-ocean" rocks to form. Keep in mind the video that shows rocks being formed right in front of our eyes...not years!
Study revises view of ocean volcanoes
Rocks formed by underwater volcanoes are much younger than believed, indicating eruptions are more frequent than suspected, researchers led by a University of Hawaii-Manoa scientist have discovered.
Researchers had thought it took a few thousand years for rocks to form in the deep ocean, "but we know for most rocks we studied, it has to be" less, said Ken Rubin, geologist-geophysicist at the UH School of Ocean and Earth Science and Technology. "We're talking about a handful of decades for most of these rocks."
Rubin's team used natural radioactive isotopes in young lava flows on the sea floor to model how long it takes for rock to melt and rise from beneath the Earth's crust to where it solidifies and builds up at the deep-sea ridge. The research shows rocks could be formed in about 100 years.
Their study was reported in the recent issue of the journal Nature.
Rubin said they started the project to determine the age of mid-ocean ridge basalts.
"We expected to find the opposite signature of what we found, and when we didn't, and when we went through all the possible ways to try to explain what we found, the only way we could explain it was in the mantle during melting."
He said this led to "a cascade of implications" about the length of time for rocks to percolate up from the mantle -- the layer between the Earth's crust and core -- and the time they spend in the crust, which "became shorter than people thought.
"Melts migrate very, very quickly up the mantle from the depths where they erupt," Rubin said, adding that magma may rise as much as six miles a year.
The findings suggest that mid-ocean volcanoes are erupting more often than believed, with rapidly fluctuating geological, biological and chemical conditions allowing unusual biological communities on the sea floor to thrive, Rubin said.
XtnYoda wonders, "What is it mankind is doing to cause this increase in volcanic activity? Surely it must be mankind's fault?"