[Geysers] Fan & Mortar (8/8 7:09) and Giant hot period -- Stephens

[lynn stephens]

Fan & Mortar erupted this morning (8/8) at 7:09.  The eruption was preceded by a double river vent pause with plenty of Main Vent splashing.  There were also three eruptions of Bottom Vent during the second pause--the first one lasting 8m50s, the second one lasting 8m40s, and the third one lasting about 7 minutes.  River Vent came on at 6:38, Gold at 06:40 and Angle at 06:42.  High Vent was erupting 6 feet high with Gold Vent non existent at 06:57.  At 06:58 Main Vent sent a splash into East Vent.  Gold then started to rejuvenate and at 07:02 the three vents (High, Gold, and Angle) finally went into a classic lock with all three vents participating in the lock.  Main Vent had a splash at 07:06, another at 07:07, filled at 07:07, and then at 07:08 was having sustained splashing.  East Vent finally initiated the eruption at 07:09 and Main Vent joined in a few seconds later.  The first surge barely cleared the boardwalk.  As Kitt said, "It's strange to be able to fit the entire 
 eruption (of both Fan and Mortar) into the camera lens."  The eruption throught out several sizeable rocks.  Upper Mortar started 2 1/2 minutes after East Vent and Lower Mortar joined in a minute later.  Just after Lower Mortar started, Main Vent cleared the boardwalk a second time (missing the jogger on her second pass through the eruption).  Fan's eruption never was very strong.  East Vent did participate in the entire eruption.  Duration of the water 28 minutes 10-15 seconds.

Viewing conditions were almost as good as the last eruption--just enough wind to blow the steam away from the boardwalk so we could see the water in each individual vent.  We had occasional rainbows in the eruption (when the sun came over the hill and peeked through the clouds).  

Thanks to Steve Robinson for giving the early radio morning call that enabled four of us to join him for the eruption.  

On another note:  While I was biking down to F&M this morning, I looked over at Giant's platform, saw Bijou off, and Mastiff boiling up about 12 - 18 inches.  Since this was about about 20 mintues after the start of a Grotto eruption, I stopped to watch. Feather Vent started a couple minutes later.  I had stayed on the bike path, and the platform was fairly steamy so I don't know how many vents other than Feather Vent and the southwest vents participated in the hot period and whether Mastiff ever got any higher.  The hot period lasted about 4 mintues 30 seconds.  This was the first hot period reported since the Giant eruption, but I don't think anyone was in the Upper Basin yesterday looking for Giant hot periods, so there may have been earlier hot periods that were missed.  

Lynn Stephens 
 
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