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Geysers of the World   

Geysers of Yellowstone   



Electronically Recorded Geyser Activity
Compiled by Ralph Taylor

If you have questions about the electronic data or wish more information about the data or how to interpret it, contact the GOSA directors at directors@gosa.org

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Recent Geyser Activity in 2011Recent Geyser Activity in 2011
Recent Geyser Activity in 2010Recent Geyser Activity in 2010
Recent Geyser Activity in 2009Recent Geyser Activity in 2009
Recent Geyser Activity in 2008Recent Geyser Activity in 2008
Recent Geyser Activity in 2007Recent Geyser Activity in 2007
Recent Geyser Activity in 2006Recent Geyser Activity in 2006
Recent Geyser Activity in 2005Recent Geyser Activity in 2005
Recent Geyser Activity in 2004 
Recent Geyser Activity in 2003 
Recent Geyser Activity in 2002 

Monthly Summaries
M110301 Monthly Summaries for March 2011.pdf
M110201 Monthly Summaries for February 2011.pdf
M110101 Monthly Summaries for January 2011.pdf
M101201 Monthly Summaries for December 2010.pdf
M101101 Monthly Summaries for November 2010.pdf
M101001 Monthly Summaries for October 2010.pdf
M100901 Monthly Summaries for September 2010.pdf
M100801 Monthly Summaries for August 2010.pdf
M100701 Monthly Summaries for July 2010.pdf
M100601 Monthly Summaries for June 2010.pdf
M100501 Monthly Summaries for May 2010.pdf
M100401 Monthly Summaries for April 2010.pdf
M100301 Monthly Summaries for March 2010.pdf
M100201 Monthly Summaries for February 2010.pdf
M100101 Monthly Summaries for January 2010.pdf
M091201 Monthly Summaries for December 2009.pdf
M091101 Monthly Summaries for November 2009.pdf
M091001 Monthly Summaries for October 2009.pdf
M090901 Monthly Summaries for September 2009.pdf
M090101 Monthly Summaries for January 2009.pdf

Electronically Monitored Geysers
A-1 Geyser
Artemisia Geyser
Aurum Geyser
Baby Daisy Geyser
Beehive Geyser
Castle Geyser
Daisy Geyser
Depression Geyser
Echinus Geyser
Fountain Geyser
Giant Geyser
Grand Geyser
Great Fountain Geyser
Grotto Geyser
Lion Geyser
Little Cub Geyser
Little Squirt
Logbridge Geyser
Lone Pine Geyser
Narcissus Geyser
Oblong Geyser
Old Faithful
Pink Geyser
Plate Geyser
Plume Geyser
Pyramid Geyser
Riverside Geyser
Spouter Geyser
West Triplet
White Dome Geyser

2000 Geyser Activity from Data Loggers

2000 Geyser Activity from Data Loggers


by Ralph Taylor


As many of you may know, I have had a research permit for the past four years to monitor geyser activity using electronic data loggers.  For those years I also assisted Tim Thompson, the Geothermal Technician, by downloading and redeploying the National Park Service data loggers late in the season after Tim left the Park.  This summer one of my jobs as an NPS volunteer for Nancy Hinman was the deployment and management of the NPS data loggers in addition to my own loggers.  At the start of the summer we had 16 loggers between my loggers and the NPS loggers.  Over the course of this summer we acquired several more; the total is now 29 loggers, 25 of which are currently in use (the other four just arrived).

Perhaps a little introduction to data logger terminology is in order.  A data logger is a device that records some kind of information (in our case, temperature) at user-specified intervals.  The logger itself uses a single chip microcomputer and a memory chip to record the data as required.  The sensor for the loggers we use is a thermistor, an electrical resistor with the property that the resistance to electrical current varies with temperature.  The logger measures the temperature by measuring the resistance of the thermistor and uses a calibration chart or equation to determine the actual temperature.  The logger is deployed by placing the thermistor in a location where the runoff water from an eruption or overflow passes over the sensor.  The logger itself is located in a sheltered location nearby.  The NPS requires that data loggers on front country features be placed out of sight, so we typically bury the logger in sinter sand, cover it with rocks or logs, or otherwise attempt (usually with fair success) to keep it out of sight.

The logger must be launched to start its task of data collection.  To launch the logger, the logger is connected to a computer using a serial port cable.  Software provided by the logger manufacturer communicates with the logger and allows the user to specify the intervals at which the temperature is measured, whether to log temperature in degrees Celsius or Fahrenheit, and to specify a title for the data set that is collected.  Once launched, the logger samples the temperature at the specified intervals and stores the information in its memory.

At appropriate intervals the data in the logger must be collected.  This is downloading, and is done by connecting the logger to a computer using the serial cable and performing the download using the software provided by the manufacturer.  Some of the loggers we are using can be downloaded and relaunched using a pocket-sized shuttle that transfers the data from the logger to the shuttle memory and relaunches the logger.  The shuttle must then be connected to a computer to recover the data.

The data collected by the download process is in a binary file in a format defined by the logger manufacturer.  The logger software that we use can graph the temperature as a function of time, allowing zoom and pan to examine any portion of the data closely.  The temperature data can also be exported as a text file containing date, time, and temperature data.

For most geysers the temperature graph is fairly easy to interpret.  For example, the graph shown at the right is from Grand Geyser using the Hobo Pro data logger that GOSA purchased for the Old Faithful Interpreters.  The graph clearly shows two eruptions of Grand Geyser (the two tall narrow peaks), followed by Vent and Turban afterplay.  Next, there is a period of no overflow, then a shorter peak (about 40°C) caused by the Vent and Turban restart.  Finally, the long period of inactivity follows, and then the Turban cycles are visible once overflow resumes.

The zoom capability allows one to look at just a portion of the graph, for example, the actual eruption start, and to determine the time accurately.  The graph shown at the right is the first eruption from the previous graph with the actual temperature points marked.  From the graph it is clear that the time of the sharp rise in temperature was 11:08.  The actual start time of the eruption must be compared with the time from the logger to determine time lag from when the eruption starts until the hot water reaches the sensor (for Grand, the sensor is under the boardwalk, and water takes well over a minute to reach the sensor).  Electronic times are recorded in the OFVC logbook with an “E” after the time to show that the times are derived from a data logger.  These times are not corrected for lag, and are also affected by the sample time interval.  For Grand, we generally sample at 30 second intervals, so the electronically detected start time may be an additional 30 seconds late.  These lag and sample time errors affect the actual start time detected, but do not affect the calculation of intervals and averages.

Detection of eruption times by examining the graph is time consuming and is impractical with almost 30 loggers deployed, some on geysers that erupt more than 30 times a day like Plume.  Over the years that I have been using loggers, I have written software to detect the eruptions automatically, and this allows the information from each week’s downloads to be analyzed and summarized in about one (long) day.  The summary statistics are the maximum, minimum, mean (average), and median interval for the past week, month, and season.  The median value is the value that is the middle value in a sorted list of the intervals.  The median is often more indicative of the “typical” interval than the arithmetic average, since one or two exceptionally long or short intervals can shift the mean, but the median is not so affected.  The summary table is kept under the glass in the “ice cream window” at the Visitor Center and is posted on the GOSA website.

Some Results from Summer 2000

Now that we have covered all the boring details of how these gadgets work, let’s look at some results.  For this article we will discuss only the results for the 2000 summer season; the results from previous years will have to wait for a future article.

There are monitors on 19 front-country geysers at this writing.  Some have been in place since May, others were acquired during the summer and have only been in place a month or so.  This article covers only the highlights; a more in-depth examination is more suited for a GOSA Transactions article.

Geyser Hill

I have had an interest in Geyser Hill for many years, and my research permit is primarily aimed at monitoring activity there.  There are loggers on Aurum, Lion, Little Cub, Depression, Plume, Plate, and Boardwalk Geysers.


As we have come to expect, dry weather resulted in long and erratic intervals for this geyser.  The logger was first deployed in late June after the wet weather ended.  There were only a handful of intervals in the usual “short interval” range of 2:30 to 2:45, (six under 2:35, and only 24 between 2:35 and 3:00.  During the previous few years, these short intervals have been much more common, and recurred for a few days following heavy rain.  This year, even after rainfall, the sub-2:45 intervals did not occur.  There were ten intervals over eight hours, one reaching 11:58 on 4 August.  For the three months for which data is available there was a slight trend to increased intervals, with a few periods of a 2-3 days of shorter intervals following wet weather.

We had an autumn snow starting on 21 September, with about a foot of accumulation at Old Faithful (and with most of the roads closed for a day).  Starting at midnight on the 22nd, about the time the snow started to accumulate, Aurum’s intervals dropped to between 2 hours 31 minutes and four hours.  The short intervals only continued until the snow melted; long intervals resumed at noon on 24 September.


The logger on Lion has a most unfriendly environment, as the logger is immersed in very hot water on every eruption.  I had one logger destroyed here, but the current logger, in a waterproof case, has survived for both 1999 and 2000 so far.  This summer’s activity was fairly uniform, with only a few really long intervals between series—two intervals in late July were well over 12 hours, but the great majority of initial eruption to initial eruption intervals were between six and ten hours, with the median series interval being 7:29.  The intervals between series gradually decreased from about 8:30 early in the summer to the present average of around seven hours.

The big change this summer from the behavior in the past few years was the total absence of long series.  The longest series recorded was five eruptions, and there were only three of these, all of which included a minor eruption.  Fully 58% of the series consisted of two eruptions.  As has been the case for the three years that I have monitored Lion, there is only a weak relationship between the number of eruptions in a series and the following interval.

Little Cub

Little Cub is a good example of where a data logger can reveal information about a geyser that is often seen but not often recorded.  The logbook has large numbers of “in eruption” and “near start” notations, so there are few intervals available from that source, and almost none during the night hours.  With the data logger it is possible to record intervals and durations with pretty good accuracy (the end of the eruption is difficult to determine exactly from the temperature record).

This year, Little Cub’s intervals have been fairly steady at about 1 hour 22 minutes all summer, until late September.  Early in the season, until about the first of August, there were occasional short intervals, some under one hour, which tended to occur in the afternoon between 12:00 and 18:00.  This trend to a diurnal pattern early in the season has been apparent in 1998 and 1999, to a greater extent than in 2000.  After early August, there was a cyclic variation of intervals with a period for the whole cycle of about one week, plus or minus a day or two.  The periods of longer intervals appeared to coincide (within a day or so) with SMax as indicated by eruptions of Little Squirt. 

On 8 September there was a cycle with noticeably longer intervals, and especially with an absence of short intervals.  The intervals returned to normal 1:25 or so until 19 September when there was an interval of 1:51 recorded, followed by two days (again, the snow days…) when the intervals rose to about 1:40.  The graph at right shows the Little Cub intervals for September.  Note the large peak (with one interval at almost three hours).  It is not certain that there was no eruption at that time, but there is no trace of it on the temperature graph. 

The data show that Little Cub has had its short intervals (below 1:15) between 12:00 and 18:00, and its long intervals (over 1:35) between 14:00 and 22:00.  These are a few interesting anomalies for research minded geyser gazers to ponder.


During the summer of 2000,Depression Geyser was very regular, with a median interval of 5:59 and a standard deviation of just 27 minutes.  The great majority of intervals fell between 5:30 and 6:45.  As usual, the long intervals were associated with strong west winds.  There appears to be a cyclic variation of intervals with about a three-day period, but the trend is not strong.  Recorded durations were all in the four-minute range.


Plume has been steady at about 40 minutes for the whole season.  The daily range in intervals tends to be within a 12-minute spread.  There was a trend to shorter intervals during the last two weeks of June (monitoring started on 16 June), then the intervals stabilized in the 38-minute daily median range.  There is a noticeable but small (about 3 minute) variation in the intervals on a three to five day cycle; the minimum intervals tend to occur around the time of Little Squirt eruptions.  A few instances of long intervals associated with heavy rain (apparently due to cold rainwater entering the system) occurred.  There were no Giantess eruptions, and no other geysers appear to have affected Plume’s intervals.  A pronounced dip in intervals to less than 40 minutes around 8 September did not appear to correlate with any other monitored geyser activity.  The intervals rose over the following week to about 44 minutes, and then returned to 41 minutes or so late in the week.  A similar dip in intervals occurred on 20-21 September, followed by a gradual increase in intervals to 43 minutes by the 23rd, with some intervals as long as 50 minutes by the 25th.  On the 23rd and 24th the intervals varied from 37 to 47 minutes.  It is interesting to note that the sudden changes in Plume’s intervals occurred at about the same time as the sudden changes in Little Cub’s intervals.

Plate and Boardwalk

These two geysers are closely related spatially, lying about 10 meters apart along a fracture line leading toward Giantess.  They also exhibited closely related activity this summer.  Plate Geyser had two oddities in its otherwise regular intervals this summer.  First, there were occasional long intervals for the first month that I had a logger on Plate.  These occurred at approximately weekly intervals.  During that time, Boardwalk was being seen infrequently.  Logbook entries for Boardwalk corresponded with long Plate intervals and with one short interval of just 12 minutes.

The graph nearby shows the Plate Geyser activity for the summer.  The intervals were consistent except for two short intervals until late July, when long intervals became more common.  For the part of June and most of July the intervals hovered around 1:30, then began to climb to 2:00 where they remained, varying cyclically at about weekly intervals.  This variation may have been related to SMax (shown by the dots at the top of the graph).  It appears that the longer intervals tended to occur near SMax.

In August I acquired another logger and deployed it on Boardwalk Geyser.  Once results from that logger were available it was clear that all of the long intervals of Plate Geyser were coincident with Boardwalk eruptions, and that the occasional very short intervals of Plate occurred when Boardwalk either began or ended its eruptions during a Plate eruption.  Not every instance of Plate and Boardwalk concerted eruptions resulted in the odd double eruptions of Plate, but many did. 

The graph to the right is the temperature graph of both Plate and Boardwalk, showing how the Boardwalk eruption coincides with the Plate short interval.  The top trace corresponds to the right scale and represents Plate Geyser; the bottom trace is Boardwalk Geyser.  In this case, Boardwalk started first at about 18:55, then Plate started at 19:06.  When Board­walk ended at 19:11, Plate paused for two minutes, then restarted.  Using the same combination of the two curves it became clear that Boardwalk’s eruptions caused Plate to have longer intervals following Boardwalk’s eruptions. 

Over the course of the summer, Plate’s intervals show a gradual but continuous increase from about 1:30 in June to about 2:30 in late September.  The Plate Geyser durations have also increased, from about six minutes in June to about 6:15 in September.  Boardwalk’s intervals have varied wildly, ranging from 8 to 32 hours with no discernable pattern.

Other Upper Geyser Basin Geysers

There are data loggers on Castle, Daisy, Grand, Grotto, and Oblong Geysers.  The following sections briefly discuss the results.

Castle Geyser

The Castle logger was deployed rather late in the season, so we have data from only August and September.  During that time, Castle’s intervals have remained firmly at just over 12 hours excluding minor eruptions.  There were four intervals between 13 and 14 hours, and one at 11:30, but the rest were between 11:40 and 12:30.  There have been 17 minors between 13 August and 26 September.  The interval from the minor to the subsequent major eruption ranged from 3:12 to 10:09 with the mean interval being 6:33.  The mean interval between the first two major eruptions following the minor was 12:58, or just about one hour longer than the normal intervals.  We hope to maintain a data logger on Castle for the whole winter, so any seasonal change should be captured.

Daisy Geyser

Daisy Geyser has been quite steady at about two hours.  There have been occasional intervals of as much as five hours (on 17 May) and numerous intervals between 2:25 and 2:30, mostly before 20 June.  There were also several long intervals (2:30 to 3:15) on 4 and 5 August.  The only recent long interval was 3:22 on 17 September at 10:19.  On the whole, Daisy has been quite regular, rarely falling outside the prediction window.

Grand Geyser

Grand Geyser, on the other hand, has been difficult to predict this summer.  It had a very sudden change in interval from about 14 hours to about 9 hours on 30 July, then just as suddenly switched back to about 14 hours on 28 August.  The intervals declined again, but this time gradually over a week’s time starting on 14 September, but then reverted to 14 hours on 26 September.  Note also in the graph that there was a noticeable shift from 12 hours to 14 hours at the end of June.  There were a few technical problems with the logger that caused us to miss several eruptions; the gaps were filled in by data provided by Mary Beth Schwarz and Heinrich Koenig.

Grotto Geyser

The logger on Grotto Geyser showed that there have been marathon eruptions about every other day.  On one occasion, on 7 and 8 September, there were consecutive “marathon” eruptions of 14:32 and 13:55 duration respectively.  Apart from this one occasion, “marathon” eruptions were separated by four or five “normal” eruptions.

Oblong Geyser

Oblong Geyser has had an unusual summer.  The data logger has been deployed since 13 July.  During that time, Oblong has been erupting in series, with from one to five eruptions in a series.  For most of the summer the series were two eruptions long, with the second eruption following the first by about three hours.  After 22 July, the intervals between series ranged between 16 and 52 hours, much to the dismay of Oblong fans.  The graph shows the scatter of the intervals clearly.

An interesting trend was the appearance of longer series starting on 17 September.  There was a series of five eruptions on 25 September, the last series for which data is available at this writing.  Could the increase in series length be somehow related to the emergence of Giant from its period of dormancy?

Lower Geyser Basin

Data loggers are deployed on Fountain Geyser, Great Fountain Geyser, and Silex Spring at present.  The loggers on Fountain Geyser and Silex Spring were deployed after the initial eruptions of Silex Spring once some loggers became available.  I will not discuss the Silex Spring results here since another article covers that subject.

Fountain Geyser

After some initial technical difficulties, we have a data logger on Fountain Geyser.  The data only covers the period from 19 August to late September.  In brief, Fountain’s intervals varied widely, ranging from 4:00 to 11:30.  There was a definite increase in intervals in late August (between 27 and 31 August) from just over seven hours to about eight hours.  The median intervals have remained around eight hours through September, and the shortest intervals have been about seven hours.

Great Fountain Geyser

Through July, Great Fountain maintained median intervals around 10:30 with numerous intervals over 13 hours.  During August and early September the long intervals jumped to as much as 16:30 on several occasions, and for much of this time a 90% prediction window was plus or minus three hours.  On 21 September, Great Fountain went into “wild phase” eruptions for at least five days.  This wild phase was preceded by two eruptions only 4:18 apart, occurring at 06:41 and 10:59.  NPS personnel or geyser gazers witnessed neither eruption as far as I can tell, so we do not really know what these eruptions were like.  Interestingly, the wild phase that started on 21 February also began with two eruptions about four hours apart.

Other Geyser

Echinus and Lone Pine Geysers were monitored for most of the summer.  Data loggers have also been deployed on some less well-known geysers this summer, but I am unable to discuss these because of space.

Echinus Geyser

Echinus Geyser has been monitored for many years.  In the past two years Echinus has stopped its regular intervals of under an hour and has become a relatively unpredictable geyser.  The data logger showed an interesting pattern of eruption intervals, as shown in the graph below.

The tall spikes on the graph represent long intervals, some over five hours.  A detailed look at the temperature record revealed that these long intervals were actually a “normal” 1:45 interval that had several temperature peaks that correspond to periods of overflow and boiling.  These “false start” events each result in a delay of just about an hour.  The really long intervals had four or five of these overflow events. 

The period between 15 July and 25 July was the period immediately following a basin-wide Disturbance.  Note that Echinus became quite regular for these two weeks, and then resumed its erratic behavior.  By about 5 August, Echinus had settled into a pattern of a day or so of regular 1:45 intervals, followed by three or four days of erratic, long intervals interspersed with shorter intervals.  The periodicity of the long intervals is an intriguing puzzle at present.

Lone Pine Geyser

Bronco Grigg and I have been monitoring Lone Pine Geyser for several seasons now.  Generally, the intervals average 16 hours, with some long and short intervals (over an hour longer or shorter) early in the summer, then periods of stable intervals.  This summer from 4 July until late September the intervals were all between 15:30 and 17:00.  Late in September one very long (22-hour) interval occurred on 22 September.  Perhaps coincidentally, this was during the 12-inch snowstorm.  A period of a week in mid-September and another period in late September are unrecorded since a coyote decided to munch the wire leading to the thermistor.  I replaced the thermistor and wire, and carefully buried the logger and wire under more rocks and tree branches.  Unfortunately the coyote was more persistent than most and managed to destroy a second sensor.  Such are the tribulations of electronic geyser monitoring.  Thermistors make expensive snacks for coyotes!

I hope this not-so-brief summary of our electronic monitoring has been interesting.  Nancy Hinman, the Yellowstone Geothermal Geologist is looking into the monitoring program, so we can expect a more structured approach to monitoring of the thermal features in the future.  One result of the large number of data loggers is a growing mass of data files, and one of the ongoing projects is cataloging these files with the view to making them accessible to researchers.  One of my projects is analyzing the temperature records and producing the analysis that I have briefly discussed here.  We hope to make some or all of the analysis available on the GOSA web site in the future.

Please note - this site is currently under constuction. Please visit for more information.  Last update 01-29-2017

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