Viewing Inside the Earth

Roland Piquepaille writes "Last week, a study released by Princeton University said that geoscientists have captured images of the interior of the Earth by using techniques similar to body scanning by physicians. This study also revealed in-depth structures which might explain how our planet is changing -- and aging. They studied more than 86,000 earthquakes which occurred since 1964. And they found 32 "mantle plumes" which are believed to cause island chains, such as the Hawaiian Islands and Iceland. They have been conjectured thirty years ago, but this is the first visual evidence they exist. This overview contains more details and references, including a rendering of mantle plumes in action."

Comments

seismic survey

[eyenot]

another ramp up in seismic survey was reported in this article in the san francisco chronicle.

Re:seismic survey

[eyenot]

this new research grant seems to follow pretty closely on the heels of new activity occuring at yellowstone national park, described here, here, and here (where you can also buy your own survey equipment.)

apparently, yellowstone park is right on top of a vent or something that has exploded catastrophically and according to some is overdue to do the same soon.

i'm willing to bet that the funding discussed in the article i linked to above:

Grants totaling $319 million from the National Science Foundation have been awarded to cover the first five years of the major new project, called EarthScope. Work has already begun on its array of instruments and facilities, which will provide the tools for decades of future detailed studies.

... has eveything to do with attempting to determine just how soon and how badly North America is going to be covered with ash and oochi-hot burning lava. Cool, or what?

Offtopic sidenote...

[_Pinky_]

While predicition of seismic and volcanic events is still, well, progressing... Detection and tracking of such an event is very much doable...

A tsunami resulting from a seismic event can be devistating, however the landing times can be predicted... The WestCoast/Alaska Tsunami Warning Center (US specific, though I'm sure there are others..) has a page (http://wcatwc.arh.noaa.gov), that include papers, faqs, and also nice charts showing if an eartquake hit how long would it take the wave to hit (http://wcatwc.arh.noaa.gov/ttt/ttt.htm)

Volcanic eruptions also are interesting in that they tend to throw up ash detectable via satellites... On the NOAA polar orbitals, channel 4 (10.3-11.3 microns) minus channel 5 (11.5-12.5 microns) shows most plumes... A good website for more information is NESDIS's volcano page (http://www.ssd.noaa.gov/VAAC/)

Shame it requires earthquakes

[CaptainAlbert]

I read the headline and immediately thought, wouldn't it be great if we could map the interior of other planets, or the moon? The knowledge we have about what lies beneath the surface of Mercury, Venus and Mars seems to be mostly speculation, with no easy way of investigating. But on a body without active plate tectonics, I guess this technique wouldn't be usable at all. I suppose there are other sources of disturbance such as significant meteorite impacts, but they're much rarer than earthquakes (on Earth, anyway).

Also, does this method rely on the liquid nature of the mantle? Would these acoustic waves propagate as effectively through solid rock (I guess not)? So, even if we could create the effect of an earthquake on, say, the moon, would it even help?

(should get back down to Earth, really!) :)

Plumes not universally accepted

[pongo000]

There is a growing movement in the geosciences that claims there is no evidence pointing to "mantle plumes." Everyone knows /. readers are well-balanced and open to new ideas, so in that spirit I offer up this link to the UK Geological Society.

Remember, an open mind is a terrible thing to waste.

Re:Resolution?

[The Fun Guy]

Uranium is rarely, if ever, found in the pure metallic form. Uranium has a valence of 6, forms uranium oxides very readily, and doesn't lose the oxygen without a lot of chemical coaxing. These oxides would rarely break down under natural conditions to free up the pure metal. Uranium is indeed denser than iron, and would be expected to sink, but uranium oxides are lighter, and float up to the mantle.