[Geysers] Pink Cone Minors or Mid-Cycle Splashing

[Lynn Stephens]

TS Bryan wrote:
 
"I look forward to your thing about Pink Cone minors -- surely minors or  
splashing have to do with the abrupt jumps in eruption times."
 
I think there are two different types of impacts that minors or mid-cycle splashing could have on subsequent eruption times.  (As a point of clarification, mid-cycle splashing occurrs about half to two-thirds of the way through the expected interval and is not to be confused with the splashing that sometimes starts an hour or so before the expected time of the next major.) 
 
Case 1 mid-cycle splashing or minor does not build to a major.  Sample of one, where the minors did not affect the interval, as you reported in the 1991 July-August issue of the Sput:  "As seen by both John Muller and Marie Wolf, these resembled the initial splashes of a full eruption, but that didn't take place until hours later--right on schedule, by the way, after an interval of just about 16 hours."  (Emphasis added.  Lynn's sigh--Oh for a return to the days of 16 hour intervals on Pink Cone.)
    Unfortunately I couldn't find any other cases where a closed interval major to major interrupted by mid-cycle splashing or Pink Cone minors could be calculated, which is why I concluded there just wasn't enough data to determine the impact Pink Cone minors have on the subsequent interval.
    In the case of the 6 minute minor witnessed by the Dunns and Freunds on 6/28/2015 at 1720:  Intervals have been running about 20 1/2 to 24 hours this year.  A Pink Cone major was reported on June 27 at 2001.  The next major was reported at 2007 on June 30.  Presumably that was three major to major intervals with the first major to major interrupted by the Pink Cone minor.  This could have been 3 24 hour intervals with no jump in the interval as a result of the minor.  It could have been 3 24 hour intervals with more than one of the major to major intervals interrupted by a Pink Cone minor; or, for example, it could have been a 30 hour interval major to major interrupted by the PInk Cone minor followed by two 21 hour major to major intervals with neither one of the 24 hour major to major intervals interrupted by a Pink Cone minor.  
    As a side note--do I think the 27 to 28 hour closed intervals I recorded in prior summers were caused by a Pink Cone minor?  No, because when I arrived to start the observation period, almost always at the opening of a Pink Cone window, the platform was not wet and I did not witness anything other than Pink Cone splashing that normally occurs.
 
    I'm just not willing to draw a conclusion based on the one known closed interval involving mid-cycle splashing.
    
Case 2 mid-cycle splashing or minor builds to a major:  In 1995-1999 when I saw a couple cases where the minor or mid-cycle splashing built to a major, then yes, the interval did take an abrupt jump, i.e. a decrease.  
 
     You're right.  Here, by definition "mid-cycle" splashing building to a major is going to result in that major to major interval showing an abrupt jump, i.e., decrease, in eruption times.  I was not clear that I don't know what impact minor induced major has on the subsequent major to major interval.  Because the major resulting from mid-cycle splashing was not preceded or accompanied by activity from the road bubblers, and the major had a shorter than usual duration, it seems to me that major resulted in an apparent lesser expenditure of energy than a normal major eruption, and so might result in a decrease on the susbequent major to major interval.  Unfortunately, I can't find data to either support or disprove what I think might happen, so I'm not willing to draw any conclusion.
 
Lynn
 
 
 
 
 
 
 



 		 	   		  
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