[Geysers] Geyser Report: Fan & Mortar details, June 29

[Tara Cross]

For those who are interested, here are the full details from the June 29 Fan 
and Mortar eruption.

Fan & Mortar had two observed event cycles on the 28th, both of them rather 
weak.  The first (1430-1530) was a double river pause with moderate 
splashing in Main Vent.  I might have been more excited about the double 
pause if the 2nd pause had lasted more than 2 minutes, but Main Vent never 
seemed very interested in keeping things going so it didn't surprise me when 
the water levels fizzled.  The second (1840-1920) was a single river pause 
lasting only 5 minutes with no Main Vent splashing.

Fan & Mortar were unobserved from 2100 on the 28th until roughly 0530 on the 
29th.  There was a weak Gold pause around 0830, after which the system 
reverted to garbage mode for a few hours.  Fortunately, the Hill People were 
at their post and called water in Beehive's Indicator, giving me barely 
enough time (12 min.) to make it to the Hill for a fine Beehive eruption at 
1210.

Upon returning to F&M I observed several more garbage cycles with 
continuous, obnoxious splashing from Angle.  However, everything--including 
Angle--shut off at 1538 and by 1550 I was watching Main Vent with interest, 
trying to coax it into doing something while the sun was unobscured by 
clouds.  Events then took place as follows:

1600 River Vent on
1610 River Vent off (River pause)
1612 Main Vent splash; splashing increased gradually throughout the first 
pause
1624 Bottom Vent (d=25s), accompanied by terrific water levels in Lower 
Mortar, something I hadn't seen in a long time
1626 River Vent on
1635 River Vent off (River pause); Main Vent had several very nice splashes 
during the 2nd pause, along with persistent low splashing
1643 River Vent on, continued Main Vent splashing
1644 Bottom Vent (d=26s)
1653 River Vent off (River pause, making a triple pause)
1700 River on
1703 Bottom Vent (d=27s)
1706 Gold Vent on with excellent water levels
1709 Angle Vent on, water levels remained very good
1722 High Vent in lock
1724 Upper Mortar surge, Gold Vent joins in lock (Angle never quite did)
1725 Fan and Mortar, East Vent start

Water levels looked great as soon as Gold came on, and 16 minutes after 
River came on High Vent began to drool constantly.  It looked as though the 
minor vents were going to go into a lock at the 18-minute mark but then they 
dropped back down.  After that they built up again, with High erupting 
steadily first to a foot, then to 3 feet, then finally to 6-8 feet.  During 
the lock, rumbling could be heard in the system and East Vent was steaming 
heavily.  Finally at 24 minutes Upper Mortar had a cone-filling surge, and 
East Vent initiated the eruption a minute later.

The eruption was quite strong, though the wind direction was rather poor for 
viewing.  Main Vent, aided by wind, was reaching into and beyond Backwater 
Spring, and Lower Mortar put on a fine show as well.  Several gazers were 
enjoying their first Fan & Mortar eruption and they got a good one.

Some general observations:  The water levels in Lower Mortar during the 
first pause were the best I have seen in a long time, probably since late 
2003.  There was no hint of it actually having a minor eruption, but it was 
still nice to see standing water and "fuzzballs" again.  Estimating roughly, 
gazers have observed around 60 full eruption cycles since 2000; only one of 
those was a triple pause cycle (Sept. 7, 2002).  There had been a triple 
pause cycle prior to the eruption that took place in the early hours of June 
26, so I didn't know what to expect this time around.  However, the water 
levels on this cycle were so much better than any other that I had observed 
that I had a good feeling about it from the time Gold came on.

By the way, special thanks to Karl Hoppe for sharing information about the 
June 22 eruption.

--Tara Cross
fanandmortar at hotmail.com