Tuesday, September 13, 2005

Poor geology reporting

This has got to be one of the more confusing statements I've ever read in a news report:
...the unnamed bulge was created because of a big cavity, estimated to be about 4.5 miles below the surface, that is filling with fluid.

The fluid is likely magma, but could also be water. It was described in the report as a lake 1 mile across and 65 feet deep.

Eh? A lake one mile across and 65 feet deep? 4.5 miles below the surface? That is a REALLY poor way to describe it, seeing as many people already believe that water is found in giant underground lakes instead of in pore spaces of rocks. Maybe this could be a better way to put it: "The amount of fluid causing the earth to bulge would fill a lake one mile across and 65 feet deep."

If that's what is even meant in the report. It's terribly unclear, and misleading to boot. And I'm probably one of about sixteen people in the world who even care.


Matthew said...

I'm also unsure what it means--and I'm one of the 16 other people who would actually care. I'm not picturing an actual cavity 4.5 miles under the surface, I don't think that would hold up, but a) what was keeping the fluid out of that area before and b) why would it being forced into the pore space in the rock be causing a bulge in the surface? (i.e., what specific pressure is causing the fluid to fill up more than what would normally be able to fill only the pore spaces in the rocks and no more?)

Actually what it sounds like is some sort of batholith forming, which would be of magma. I don't know what liquid water would be doing in such quantity 4.5 miles down, but who knows? In that case, it would be an actual cavity, and the direction rocks at that point are weakest laterally rather than vertically, making it only 65 feet "deep" while being a mile wide. Stupid english units, why aren't they using SI? You know the scientists were, so you're losing informatio when you convert it.

Matthew said...

This article states it a little better and removes that water possibility.