reply to post by Dianec
Ok so, further information about this from another informed little birdie- it appears that:
1) Helium measurements at YS go as far back as the 70's.
2) There have been no significant long term changes in helium output there
3) It is an expensive process, but still has been done numerous times over the years
4) They are 10 years into a long-term study of this
5) Somewhere, some tard got the idea that this was some kind of eruption precursor, when it is not. Not at all. For example, increases in Helium have
been noted at Mammoth Mountain in Long Valley, and associated with earthquake swarms, but have there been any eruptions there? NO! So people,
completely disassociate this please with any preconceived notions of this being any kind of eruption precursor. Because it is not. It is simply
degassing of the helium in the crust/mantle, accelerated by the YS hotspot.
And that's all I can print. Hope that helps to alleviate any concerns.
ETA: Increases in helium can be an eruption precursor, but only to the extent that any of the other eruption precursors are- in other words, an
increase in it does not guarantee an eruption. But note that the same can be said of any of the other eruption precursors, when taken individually. In
the case of Yellowstone, however, the study shows that it has not increased. Therefore, even if it is related to new magma intrusion (such as is
suspected of the 2008 Lake swarm), it is no more of an eruption precursor than anything else. Show me harmonic tremor and extreme seismicity, and
you'll make a believer out of me that YS is about to erupt.
At this point, there has never even been a long period event detected at YS, much less any kind of tremor. And melt ratio is estimated to be far too
low to support an imminent eruption. Jake himself said he thought YS might be "finished." Volcanoes, and large calderas, do go extinct you know- cause
there are more than few that have done just that. I made this edit to clarify that I believe that at YS particularly, the large helium output is not
any kind of eruptive precursor, given the rest of the available information on the melt status, other degassing, CO2 emissions, water table changes,
deformation, and even the occasional seismicity above background levels. The alert level is at green. Where it should be, all things considered.
edit on Sat Mar 1st 2014 by TrueAmerican because: (no reason given)