[Geysers] Pink Cone Group and the earthquake swarm

[Lynn Stephens]

Gordon Bower wrote:  
 
> Pink Cone also appears to have changed its intervals substantially: it was seen at 1100ie Friday (end 1210) and 0940ie Saturday (end 1102), within the normal range, but had already finished and was barely even puffing steam at 0810 Sunday, pointing to an interval under 21 hours. Karen Low reported another eruption Tuesday evening for a presumed triple interval under 60 hours.  While there were individual intervals under 21 hours earlier this season, there were never two, let alone four, in a row; the average has been up around 23 or 24.
 
Thank you for the information, but I disagree that there is evidence Pink Cone has "changed its intervals substantially."  Over the past 25 years I've been watching Pink Cone, it has generally done what I termed a "jump shift" at least a couple times each summer and the shift has not been associated with an earthquake.  When Pink Cone does a "jump shift" it  throws in a really, really short interval--for example, 15 hours instead of the customary 22 or 23 or 24 hour interval.   In recent years, instead of erupting about the same time each day, it will be seen erupting at an entirely unexpected time.   I am hampered because I'm responding to this while I'm on the road and don't have my library or data sets with me, so will have to demonstrate my point with just one data point I extracted from geysertimes.org for the 2013 season.
 
Gordon bases his claim on this data set:  
   9/20 1100ie, 
   9/21 0940ie,   9/22 0810 already ended,  9/24 1739ie  rolled forward 7h59m from ie to ie
 
Pink Cone rolled forward 8 hours over the three-day period from 9/21 to 9/24.  I believe this is a "jump shift" where Pink Cone threw in an interval of 13, 14, or 15, or 16, or 17 hours rather than having individual intervals of "two, let alone four" in a row.  Here's anoter exampe from earlier in 2013 when Pink Cone rolled forward almost 7  hours over a three-day period--
   7/8 0747 to 7/11 1434ie  rolled forward 6h44m
 
Here's another example of a jump shift in 2013--July 4 1634ie to 7/8 0747.  Pink Cone had been erupting in late afternoon, early evening through July 4.  Then we lost track of Pink Cone because it threw in a "strange" interval.  When it was finally observed again on 7/8, it was erupting in the early morning, showing an 8 hour "jump shift" although in this case the "jump shift" was a backward shift rather than a forward shift.
 
I'm sorry, but Pink Cone does this--it throws in an extremely short interval every once in awhile that causes confusion and consternation to people who are trying to see Pink Cone.  Without several observations from late September/early October showing Pink Cone is routinely averaging under 20 hours rather than a single data point over a three-day period, I am unwilling to conclude that the mid-September 2013 earthquakes in the Lower Basin "substantially" changed Pink Cone's intervals.
 
Lynn Stephens 
 
 
 
 

 
 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: </geyser-list/attachments/20130928/6ce878da/attachment-0001.html>