Hi Canie. I think part of the problem may be that they were researching the time period of June to August of 1989.

The CO2 does fluctuate in the area depending on the atmospheric pressure. It may also be that there are fewer trees in the area to be affected there by giving a false indication. I tend to agree with USGS on their assessment of the CO2 situation.

It is however a sobering thought when you consider how close we were to having an eruption. It could also be said that maybe we weren’t all that close in that there was no eruption, or even an indication of one. However when you get Helium 3 you have new magma moving towards the surface. The magma chamber under Long Valley isn’t all that large so it most likely wouldn’t take very much of an increase in new magma to get a Helium 3 indication. There is a lot known about the area, but I wonder as to how much of it is understood and what it means?

As for it erupting without warning as some have said. All indications at this time are that it won’t happen. As to how much of a warning remains to be seen. Mt. Saint Helens gave considerable warning, but no one was listening. A lot was learned from that eruption that will be of immense use for the Long Valley area. Take Care…Don in creepy town