Activity in 2010

Activity in 2009


Activity Recorded by Data Logger  by Ralph Taylor 



Introduction 
When some additional data loggers became available in the late summer of 2002 we deployed one on Rift Geyser and one on West Triplet Geyser.
West Triplet Geyser is located to the southwest of Grand Geyser a few meters from the boardwalk and is known to be one of the interconnected geysers of the Grand Geyser complex. Other members of the complex are Grand Geyser, Turban Geyser, Rift Geyser, Percolator Geyser, and Vent Geyser.
The sensor for West Triplet is located a few meters downstream of the geyser formation in the runoff channel. Start times for West Triplet on the data logger lag visual times by a few minutes since no overflow occurs until the geyser has been in eruption for a few minutes.
I have written software to determine the end times for West Triplet's eruptions, but because of the gradual trailing off of the eruptions, the end times (and therefore durations) are not as accurate as the start times. At this time I do not have a quantification of the error in durations derived from logger data.



Activity in 2008 
In 2008 West Triplet has erupted about 4.5 times a day on average, with intervals ranging from about an hour and 20 minutes to 11.5 hours. The mean and median are about 4h53m (see the current statistics for specific values). The full statistics for the year are here.




The first graph shows the eruption intervals for 2008 plotted against the eruption start time and date. The intervals shows a slight decreasing trend (note the red trend line) and have a wide range. Many of the eruptions occur in pairs separated by an hour or so.

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Starting on about 29 April and continuing to 2 May, then on 910 May and 1216 May West Triplet had eruptions preceded by a dozen or more periodic short (less than 5 minute) overflows about ten minutes apart. The temperature trace for one of these episodes is shown here.




The distribution of the intervals for all of 2008 are shown in the histogram at the right. The intervals around 2h30m are the double eruptions, the ones between 5 and 10 hours are the longer intervals between pairs of eruptions.
Note that in this and the other histograms displayed here the labels shown on the Xaxis represent the upper boundary of the class, not the midpoint. Geyser times are traditionally truncated. The graph at the right has class widths of 30 minutes. The bar appearing above the label "5:00," for example, contains intervals from 4h31m through 5h00m.

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The next graph shows West Triplet's durations plotted against time and date of the eruption start.

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The duration distribution histogram is another look at the pattern of durations. The labels shown on the Xaxis represent the upper boundary of the class, not the midpoint. The durations represented by the bars over the label 1:20, for example, represents the percentage of durations between 1h15m and 1h20m.
Note the decidedly bimodal pattern of durations.

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Activity since 2002 
The graph at the right shows all of the electronically recorded intervals for West Triplet Geyser. The long gap in the spring of 2005 resulted from a logger failure. Note the gradual decline in the intervals, especially the longest intervals, between 20023 and 20056.

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The next graph shows the moving 1week median intervals. this graph suppresses the extreme values and gives a somewhat clearer picture of the changes.

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The next graph shows the monthly minimum, mean, median, and maximum intervals.

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The final graph shows the monthly minimum, mean, median, and maximum durations. As with the interval statistics, there has been little change since 2002.

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Activity in 2007
