[Geysers] Data on Grand Geyser 2012

jimscheir at aol.com jimscheir at aol.com
Tue Dec 4 08:15:06 PST 2012

I put the data I collected this year on Grand Geyser onto an Excel spreadsheet to analyze the results. I was in Yellowstone from May 3, 2012 to September 13, 2012. I acquired data beyond just times (code such as T2C) on 288 eruptions.Of these, I observed 186 personally and obtained data directly from reliable gazers for the others. I did not collect or analyze data recorded online after I left the park. I have included below information from 2011 when I had data for 164 eruptions from May 11, 2011 to October 3, 2012.

1. Monthly and total burst averages

                    2011                                                2012
Month    #observations    Burst average    #observations    Burst average

Thus the burst average was down a bit in each comparable month as well as on total average.

2. Grand (G) starts were up significantly from 2011 to 2012. Because there were 16 eruptions included in 2012 for which it was not known if Grand (G) or turban (T) started first the best information is the % of known. The Grand start % more than doubled in 2012 compared to 2012 as can be seen below.

                   2011        2012
G start %    16.23        34.93        
T start %     83.77        65.07

3. Turban and vent continued (C) more frequently in 2012 compared to 2011 rather than quitting immediately after the eruption (Q) as can be seen below

                        2011                                2012
                Number    %of known         Number    % of known
C                66            40.24                155            54.77
Q                98            59.76                128            45.23
Unknown       0                                      5

4. There were 20 2* eruptions recorded (the second burst lasted at least 1m15s) in 2012 compared to 10 in 2011 with equal numbers being T and G starts in 2012 and essentially the same proportions in 2011. 17 of the 20 in 2012 were classified as Q's as might be expected with a longer eruption.

5. The burst average in 2012 included 1 4-burst eruption (a G start) and 8 3-burst eruptions (of which 6 were T starts). For comparison in 2011 I recorded 1 6-burst eruption (a G start) and 11 3-burst eruptions (of which 10 were T starts).

In drawing any conclusions it must be remembered that there were many eruptions for which the codes were not recorded, especially early and late in the season. Because the Grand intervals were short this year there were occasional days when 3 or even 4 eruptions were recorded in 2012. Also I heard rumors of perhaps 2 additional 3-burst eruptions but I could not confirm them by finding the actual observers so I have not included them.

If anyone would like to see the original spreadsheet with the data, please contact me at jimscheir at aol.com. It is in Excel 2007.

Jim Scheirer


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