[Geysers] More on East Sentinel

[David Schwarz]

On Tue, Nov 9, 2010 at 2:43 AM, Tara Cross <fanandmortar at hotmail.com> wrote:

>
> 4) After reading Murray (Transactions IV) and Bryan (2008), I am theorizing
> that this eruption came from both of East Sentinel's vents.  The big burst I
> did see landed on the embankment, and there was obvious splatter up the hill
> past the sawhorse.  There was also a lot of matted grass and wash between
> East Sentinel's vent and the embankment, indicating that the big part of the
> eruption came from the northwest vent.  However, when I got to East Sentinel
> and could actually see water, it appeared to be having low bursts at an
> angle towards the river, which would be coming from the southeast vent.  Any
> thoughts?
>
>
   I saw two eruptions in 2001.  The first was definitely the first of the
year.  I saw it very near start because I'd been noticing strange steam
puffs from it for nearly an hour from F&M, and so had half an eye on it.  I
sprinted from the picnic table as soon as I saw the cloud go up.  When I got
there, it was in a massive, vertical eruption that at the time felt like
40ish feet, although I have no idea how accurate that is.  I realized I'd
left all my stuff, including my cameras(!) at the picnic table, so I ran
back, grabbed them, and returned as fast as I could.  By the time I got back
and got my video camera running, there were a couple of more vertical pushes
to about 10 or 15 feet, then the vent angled into the river took over.

   My impression at the time was that it was like Depression--it had one
vent that erupted and lowered the pool level, and another that took over
once the main vent was through and the pool sufficiently low.  All of the
followup eruptions I saw over the next hour were from the angled vent and
almost completely subterranean.

   The other eruption I saw was much farther in by the time I got there
because I was near Norris Pool and not paying attention when it started.
That time I saw only the angled vent.

   My guess is that all eruptions start with some kind of activity from the
vertical vent, but that it dies out, sometimes quite rapidly, sometimes
after a number of minutes, and the angled vent takes over.



> And now a question for those who have seen activity from East Sentinel:  is
> the vent in the side channel always active with major eruptions?  Mike
> Keller told me he saw it, but Murray mentions it only as a drain hole.  Was
> it active with the eruptions seen in 2002?
>

   I _think_ I remember it splashing a few inches high during the first
eruption I saw.  Nothing that would distract from the big, angry surging
thing in the crater.

David Schwarz
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