[Geysers] Trip Report 4-25 to 5-3-09

[Michael Goldberg]

Dear Stephen,

My recollection of Penta comes from its active periods in the early '90s, 
when Tardy cycles were dominant for days at a time.  Nearly all eruptions 
were initiated by bubbling in the lower vents growing into continuous 
sputtering, then finally the main vent would join in.

I've also seen solo main vent eruptions of the type you described, usually 
earlier in the cycle before Penta is filled to overflowing.  I suspect 
that when Penta is sporadic and infrequent, the occasional full eruption is 
initiated this way.  But I have no evidence to back that up.

Late in the cycle, there is a pronounced exchange of function between 
Penta and Oval Pool.  Penta drops abruptly when Oval has its intermittent 
wave periods and refills just as abruptly at their conclusion.  The water 
levels bounce around quite vigorously each time.

Were you watching Penta closely enough to see whether the main vent 
started on its own, or was it encouraged into activity by the lower vents?

Michael Goldberg
mikeg at math.jhu.edu

Stephen Eide wrote:

The Penta starts I have seen (I think six) have all started with the side 
vents and then the main vent joined in.  But three times in the last two 
years I have seen the main vent boil up to 2-4 feet for several 
seconds,only to drop out of sight.  So, for those of you who have seen 
Penta starts, do all Penta eruptions start with the side vents, or does it 
occasionally start with boiling in the main vent?