[Geysers] Geyser Report June 13 (Stephens)

[Lynn Stephens]

I don't have much new to report, but heard some misconceptions, etc. about Gemini in recent days, so thought I should describe the Gemini cycle.
 
Sometimes, but not always, Pebble drops 1-10 minutes before Gemini starts.  Prior to yesterday I had only had one case where Pebble did not give me warning so I could get on the radio to alert anyone in the Lower Basin who might be interested in seeing Gemini.  I saw one series yesterday (a series of 3), and three series today (4, 5, and 5) and there was no preliminary drop of Pebble preceding the four series.  Maureen saw the initial eruption of the series after the series of 3 I saw yesterday afternoon and reported Pebble did drop prior to the start of that series.
 
I do not believe that Gemini is "regular."  Intervals from initial to initial have varied from about 3 1/2 hours to 10 hours (estimated based on time for Pebble to come to overflow plus 6 hours of Pebble overflow).  Both the time of Gemini's activity and the "quiet period" of Gemini's cycle (end of last eruption to beginning of initial of next series) show variability.
 
Gemini's active phase:  The Gemini series can have from 3 to 9 eruptions, intervals 4 to 15 minutes apart, with no pattern.  The active phase can last from 25 to 60 minutes (excluding the series where Crack erupted).  Activity from the left vent initiates the eruption.  Activity in the right vent continues after the left vent has ceased.  No independent activity from either vent has been observed yet this season.  Pebble's water level falls during the Gemini series, although it does show slight fluctuation with Gemini's eruptions as the level is falling.  The frying pan vent in Pebble's shoulder closest to the road (near vent) stops eruption about 1-10 minutes into the Gemini series.
 
Gemini's quiet phase:  The water level in Gemini continues to rise and fall at about 10-15 minute intervals during the quiet phase.  Pebble's water level rises while Gemini is quiet.  Pebble's "near vent" starts erupting before the water level in Pebble reaches the vent.  This eruptive activity starts about 45 minues after the end of the preceding Gemini series.  Generally the frying pan vent in Pebble's far shoulder ("far vent") doesn't start erupting until the water level in Pebble has almost reached that vent.  As Pebble's water level continues to rise and covers the "near" and "far" vents, the two vents continue to erupt, sending droplets of water above Pebble's water level.  Eventually Pebble's water drowns the "far" vent, but the "near" vent continues erupting until Gemini starts it's next series.
 
Sometimes Gemini starts its next eruptive series before Pebble reaches the point where it is overflowing down the hill.  Overflow down the hill starts about 4 to 5 hours after the preceding Gemini initial.  I've seen Gemini erupt 15 minutes after Pebble's overflow started and I've seen Gemin erupt after more than 6 hours of overflow.
 
Between Maureen and myself we closed a Labial interval at 6h27m today.
 
Between Barbara and myself we had an approximate closed interval for Narcisus of about  2 1/2 hours.
 
I believe my 1557ie and 1940ie observations of Pink were also a closed pair, with an interval of about 3h40m.
 
Visitor comment of the day:  "Hey, do you know when Fountain Cone is going to erupt?"  I started my explanation with the comment that I didn't want to appear or be rude, but I didn't know where Fountain Cone was, but I did have information on White Dome.  I've heard various incorrect combinations of Red/White/Pink and Dome/Cone, but "Fountain Cone" was a new one to me.
 
Wildlife:  Sure enough, as soon as I wrote I thought the pair of mallard ducks had made the lukewarm thermal pool their home, the ducks disappeared and haven't been seen in a few days.  Scummy, orangish, material is starting to cover the pool, which may be why they abandoned it.  On the other hand, a red-tailed hawk has been seen every day for the past several days, in addition to the killdeer and mountain bluebirds in the meadow north and east of Pebble/Gemini.  Who wants to make bets on whether now that I've written about it the red-tailed hawk disappears also.  It appears the two remaining bison herds, one hanging at Madison Junction, and one in Fountain Flats, have moved on up the Mary Mountain Trail.  There are still a few lone bulls hanging around, but hopefully the major bison jams are finished for awhile.
 
Lynn Stephens
   
 		 	   		  
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