[Geysers] Giant hot periods prior to the May 24th eruption

[Graham Meech]

I had my first overnight 'Giant watch' leading to the eruption on the 24th.
With Michael Goldberg's observations from 22/23 May and mine from 23/24 we
have a fairly complete record of the hot periods at Giant for a couple of
days and there were a whole lot of them!  So here for the record is the
information from my logbook.

 

Tuesday May 22

0445ie Grotto (marathon), end 0800-0900

1433 Marathon recovery GHP, d~5m, Mastiff 1-2', India 50% wet

1713 GHP d~6m, Mastiff 1-3'

1929 GHP d=5m50s, Mastiff 1-3', some vertical surging in Giant to the bite

2033 Pause

2046 GHP d=2m52s

At this point I left for some sleep.  Bijou wasn't on strong and Mastiff was
not depth charging.  Maybe Mike can fill in any gaps in data before I
returned ~0400 on the 23rd.

2300 Grotto Fountain, no Grotto (Mike)

 

Wednesday May 23

~0100 Bathtub (Mike)

0152 Bathtub, Mastiff depth charging and strong Bijou jetting started here
and continued until Giant erupted (Mike)

0347 GHP d=2 (Mike)

0446 GHP d=2m12s

0458ie Grotto Fountain

0504 Grotto d=35m, first Grotto after the marathon, Grotto was off for over
20 hours.

0534 Bathtub

0628 GHP d=4m40s

0727 GHP d=1m40s

0827 Pause

0840 Pause

0857 GHP d=4m, vent next to Catfish splashed after hot period (it did this
after quite a few hot periods during the day)

0907 Grotto Fountain

0912 Grotto d~1h

0958 GHP d=2m10s

1106 GHP d~4m, Bijou went into steam

1201 GHP d~1m30s

1257 Bathtub

1343 Pause

1350ns Grotto Fountain

1353 Grotto

1401 Slowdown

1416 GHP d=6m25s, Mastiff 1-2', Cave boiled round the rim, Feather tried to
restart, this was the only 'good' hot period of the day

At this point I took a food break so Giant may have had a hot period before
the next one listed although the platform was dry when I returned.

1628 GHP d~1m30s

1720 Pause

1737 GHP d~3m30s

1835 GHP d=2m10s

1935 GHP d=1m45s

2039 GHP d~5 Bijou roaring but not much Mastiff overflow

Another food break so maybe a missed GHP.

2233 GHP d~4m

2241ie Grotto Fountain

2241 Grotto d~90m

2326 GHP d<1m30s

 

Thursday May 24th

0021 GHP d~4m

0117 GHP d=1m20s

0226 GHP d~4m but weak, no FS

0324 GHP d=1m40s

0352ie Grotto Fountain

0353 Grotto (still i.e. during Giants eruption)

0424 GHP d=1m20s

0522 GHP d=7m20s, India not flooded until Feather restarted and Giant
started to surge.

0532 Giant d-95m

 

It is possible there were more pauses because I took excursions to Grand and
the bathroom in between hot periods but given how strong Bijou was and the
regularity of the hot periods I don't think any were missed (except for
during the longer breaks noted in the text).  Bijou was easy to watch
overnight given how strong it was.  In a matter of seconds it would go from
vigorous to 'off'.  No need to guess if it was paused or not except for the
one time it did a slowdown.

 

Most hot periods with d>3m had Feather Satellite active and shorter ones did
not.  A couple of d~4m hot periods were weak and didn't get Feather
Satellite.

 

So like last year, weirdness at Grotto and hourly hot periods lead to a
Giant eruption.  Added to that was the strong Bijou eruption and Mastiff
depth charging for over 24 hours.

 

Go Giant!

 

Graham Meech

 

 

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