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| Activity Recorded by Data Logger - by Ralph Taylor |
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| Introduction |
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Depression Geyser has been monitored electronically since 1997. Data from 1997 to mid-2002 covers only the summer months, generally from late June to early October, but since the mid-2002 we have attempted to monitor Depression all year. There are three large gaps in the record, 27 Dec 2002 to 1 Feb 2003, 2 May 2003 to 22 June 2003, and 27 Oct 2003 to 21 Jan 2004. Two of these were caused by the logger going missing (presumably because of critters) and one because of a logger filling its memory. A short gap from 24 to 27 May occurred in 2008 when the logger memory filled.
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| Activity in 2010 |
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The overall statistics for 2010 are shown at Depression Geyser 2010 Statistics. A pdf of this summary is at Depression Geyser Recent Activity Summary.
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The interval graph shows all of the recorded intervals for 2010. The graphs for the current year are updated about every six weeks from October to June and weekly from June to the end of September. The yellow triangles show the eruption start times for Little Squirt Geyser. The Little Squirt eruption times are used as a surrogate for the so-called SMax (South [Geyser Hill] water level MAXimum), which is thought to represent a cyclic change in the hydrothermal energy on Geyser Hill. This hypothesis is described in an article in GOSA Transactions Volume IV titled Cyclic Hot Spring Activity on Geyser Hill, Upper Geyser Basin, Yellowstone National Park—Graphical and Interpretive Descriptions of the Geyser Hill Wave, Diurnal Effects, Seasonal Disturbances, Random (Chaotic?) Events, and Earthquakes by T. Scott Bryan. The green diamonds show the first eruption of each recorded Dome Geyser series. Activity in Dome geyser is also known to affect some other features on Geyser Hill.
In October 2009 Depression's intervals shortened to the three hour range and became less variable. These shortened intervals continued into 2010.
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The next graph shows the intervals for the past few months at an expanded time scale.
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The graph to the left shows Depression Geyser intervals for the last month.
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The next graph is a histogram of the distribution of intervals. Note that in this and the other histograms displayed here the labels shown on the X-axis represent the upper boundary of the class, not the midpoint. Geyser times are traditionally truncated. The graph at the right has class widths of 10 minutes. The bar appearing above the label "2:20," for example, contains intervals from 2h11m through 2h20m.
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Finally, the graph at the right shows the monthly minimum, mean, median, and maximum intervals.
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| Activity since 1997 |
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Depression's activity was been monitored only in the summer months from 1997 to 2002, so the full cycle is not shown on the graphs. The first graph shows all of the intervals recorded since 1997. The intervals show an increase in 2002, reaching a peak in late summer or early fall, then dropping to 7-8 hours until late 2003 when a rising interval trend began that continued until early 2006. The peak occurred around September-October 2006 with numerous intervals over 24 hours and many in excess of 30 hours. The trend reversed in 2007 as intervals fell below 12 hours during the summer months, then rose at the end of 2007. In 2008 the intervals initially returned to the 12-18 hour range, but by June started a dramatic rise to peak at over 100 hours, or fewer than two eruptions per week. The intervals again dropped late in 2008, but began to rise in early 2009.
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The pattern shows up more clearly in the moving one-day median interval graph .
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The final graph shows the monthly minimum, mean, median, and maximum intervals for all of the data available. This gives another view of the changes over the past decade. People who watch Depression can attest to the difficulty in catching an eruption in the past few years. Hopes that the drop in the maximum and average intervals in early 2007 heralded a return to more predictable eruptions of this underappreciated geyser proved unfounded. Indeed, by late summer of 2008 Depression had become a rare geyser indeed.
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Activity in 2009
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Activity in 2008
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Activity in 2007
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Activity in 2006
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Activity in 2005
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