Re: Where is Geology 401?

Greg Billock (
Thu, 30 Apr 1998 18:47:25 -0700 (PDT)


> afraid that my friend was one of them. I called him on Monday. He had
> helicoptered up to the mountain Saturday morning and changed his film as
> rapidly as he could. He said the entire mountain was shaking like a leaf
> that Saturday. He said he had never seen so much shaking before that day.

But I thought geology was all dry and boring. :-) :-)

> When I went back to Seattle, he showed me the photo from March superimposed
> on the photo from May, the day before. The amount of expansion of the
> mountainside was incredible. I hadn't thought that rock could be so flexible.

This is what is making the geologists concerned about the Long Valley
Caldera out here in Cal. There have been several quakes, some fairly
big, and there is upswelling going on. That caldera only blows every
several million years, I guess, but when it does, it lays ash over the
whole western U.S. :-( Hopefully it just does this every once and
a while and then goes back to sleep! ;-)

[For Norm, volcanic eruptions seem to be one of the easiest long-range
correlations to make. Glenn can probably give you a lot more details
than I can, but I've read some papers where ashfalls from volcanoes
are found worldwide (you know it is a particular one because of
isotopic markers).]