posted on Jan, 7 2014 @ 05:44 AM
Hmm, I'm not in the habit of paying for science articles, but I must admit- that one is tempting. S&F
It's hard to tell from the preview of the article alone if the full paper will dive deeper into magma composition, chemical processes, and how this
buoyancy manifests in large magma chambers. And what about partial magma crystallization, such as is suspected at Yellowstone? How does this interact
with buoyant magma, and to what degree can crystallization prevent or impede the upward flow of eruptible, buoyant magma? What ratio of buoyant magma
to crystallized (more hardened) magma needs to exist before an eruption can be predicted? I got lots of questions.
Compounding this problem is the issue of super and smaller volcanoes having different types of eruptions (both effusive and explosive) during their
lifetimes. This implies different and varying states of magma chemical composition over the volcano's eruptive cycle.
I was just reading about how at Long Valley supervolcano, that is exactly the case. I also just posted a thread about it here:
The Ongoing Long Valley Supervolcano Threat- and What Happened There in the
And is there a way through seismic tomography to gauge the degree of magma buoyancy? They often draw inferences that lower velocity zones are likely
more melted, because of the seismic propagation properties of molten rock versus solid rock. But they are also finding out that low velocity zones can
mean fractured, loose rock, too- again, compounding the problem. I just read a USGS article about them finding fractured loose rock like that through
tomography some 100 km below the New Madrid fault.
I guess what I am getting at is that it would seem buoyancy would be extremely difficult to ascertain some 10 to 25 km down (or much deeper). If they
try to do it based upon CO2 emissions, well, I don't see how they could rely much on that either- I mean read over in that Long Valley thread-
magmatic CO2 was saturating the ground in that case of the massive unrest in the 80's-90's, and Yellowstone is also producing huge amounts of it-
but, no eruptions.
And further, you still have the problem of caldera uplift and subsidence (ground deformation). Is that caused by buoyant magma or steam (hydrothermal)
? Granted, each volcano has its own unique properties, and that is why usually there are dedicated teams to study them each separately. Maybe 1000
years from now they'll finally figure this all out buried under a kilometer of ash.