[Geysers] Black Diamond on 7/29

[Mike Keller]

I spent most of my day at Black Diamond on 7/29, first arriving around
11:00am.  The Strassers and Tara Cross had been there a while before I
arrived and said it has not been seen in daylight.  When I arrived, Black
Diamond was in overflow with periodic bubbling seen over many areas of its
basin.  The water was grey/white and very murky.  In the center, slightly
off to the north, there appeared to be heavier, more consistent periods of
upwelling and bubbling.  Most of the bubbles were marble to golf ball sized.
Over the next 7 hours, the water level slowly rose about ¼”.  Starting at
1604, the bubbles coming over the main vent would occasionally be softball
sized.  Finally, at 1753, Black Diamond erupted.  There were about 7 of us
staring at the pool when it started.  It gave NO warning.  There was another
softball sized bubble, then suddenly the whole center of the pool heaved and
it was in eruption.  The eruption lasted about 20 seconds and reached as
much as 20 feet in height, being as wide as it was tall.  Loud thumping and
popping sounds could easily be heard while it was erupting.  The water color
changed from the milky grey/white to obsidian black.  It looked like it was
erupting asphalt.  The lower third of the water column was “chunky” with
rocks, gravel, and debris.  As quickly as it started, the eruption stopped.
Over the next 90 minutes there were several periods of heavy upwelling but
no further eruption was seen.  The periods of upwelling gradually diminished
until they were no longer visible at 1940.  When I left the area, Black
Diamond looked exactly as it had when I arrived at 1100.

 

MK

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