[Geysers] Geyser Activity

[Timothy Holmes]

Good stuff Lynn,  thanks for your post

TIM
W8TAH

On Sun, Jun 12, 2016, 11:13 AM Lynn Stephens <lstephens2006 at hotmail.com>
wrote:

> THIS MESSAGE IS FOR THE PERSONAL USE OF THE READERS OF THIS LISTSERV AND
> IS NOT TO BE REPRODUCED FOR ANY OTHER PURPOSE INCLUDING PUBLICATION IN THE
> SPUT.
>
> Thank you to Jake Young for setting up the geysertimes website and to Will
> Boekel and the other people who have helped make the site accessible and
> useful.
>
> The other day I overheard someone telling a visitor about the site.  The
> person then added a comment about usefulness of the average interval
> computation shown on the website.  As with any other computerized model,
> information output by the program needs to be used with caution.  Two
> problems arise with the average and median intervals calculated on
> geysertimes.  One problem is missing data.  The other problem that arises
> with some geysers is lumping intervals between various types of activity
> into a single computation.
>
> 1.  Missing data:  If the sampe size is large enough and the proportion of
> missing data is small enough then the impact of missing data can be
> reduced.  However, for example, with Great Fountain, the impact of missing
> data is not reduced.  On 6/11 when I looked at geysertimes, the average
> interval listed was 2d16h0m and the median interval listed was 12h51m.
> From May 28 (when the road opened) through the 0808E time on 6/11 there
> were 21 closed intervals and 4 double intervals.  The median of the closed
> intervals was 11h21m (as compared with 12h51m listed on geyserytimes; the
> mean of the closed intervals was 11h32m and the overall mean was also
> 11h32m compared with the 2d16h0m listed on geysertimes.)
>
> 2.  Combining intervals between multiple types of activity:  Castle Geyser
> demonstrates this problem.  When I looked at geysertimes for Castle
> activity through the eruption on 6/11 at 1457, the mean interval shown was
> 12h54m and the median was 13h51m.  When I disaggreated the intervals into
> major to major versus minor to next eruption back through eruptions on May
> 24, the mean interval for major to major was 14h09m, with a median of
> 13h56m.  While the median interval shown on geysertimes is quite close to
> the median for major to major, the mean interval is over an hour different.
>
> Summary--use the interval computations on geyser times with caution.
> Again thank you to everyone who makes this invaluable site available.
>
> Lynn Stephens
>
>
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