| Comments: | From GOSA Transactions I pg. 151: “The hot periods were lasting about 30 minutes on intervals of about 60 minutes. The hot period which began at 16:42 progressed through the usual sequence of events in the course of half an hour. Upper Mortar was surging 2 to 4 feet above the top of the cone and the hot period appeared to be about over. However instead of quitting Fan's vents renewed their activity for an additional 16 minutes continuing for 8 minutes beyond when Upper Mortar quit surging. It is possible that this event was a ‘near miss’ that might well have resulted in a ‘Grand Canyon’ start. Instead the geysers waited for the next hot period which did not begin until 18:14 an interval of 92 minutes. The eruption of Fan and Mortar began at 19:14.” |