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Geysers of the World   

Geysers of Yellowstone   



  Aurum Geyser
Feature Type: Geyser
Geyser/Spring Type: Cone geyser

Upper Geyser Basin
Geyser Hill

Aurum is a beautiful cone-type geyser. The height varies from 15-25 feet, the duration is about 90 seconds and the interval can be from less than 3 hours to many hours. During some periods, Aurum is very regular and predictable. At other times its intervals are erratic and often long. One theory is that Aurum is affected by the surface water in the meadow behind the geyser. Observations seem to indicate that when the meadow is wet and marshy, Aurum's intervals are fairly regular and usually short, about 2-4 hours. When the meadow is dry, the intervals are often erratic and anywhere from 4 hours to more than 12 hours. The meadow is usually wet in the Spring, early Summer and late Fall when there is plentiful rain and snow. In the late Summer and early Fall, the meadow is usually dry unless there has been a recent heavy rainstorm.

On a few rare occasions, Aurum has been observed to have a series of two eruptions. In these cases, the second eruption followed the first by 5-10 minutes and was of slightly shorter duration.

Aurum is a fun geyser to watch. It is close enough to the boardwalk that during a strong eruption, its angled plume can travel over and past the boardwalk. The water, after its flight through the air to the boardwalk, is warm but not scalding, so don't be too alarmed.

What to look for:
After an eruption, Aurum is quiet. Activity increases as the next eruption approaches. First splashing becomes visible in the vent. The splashing varies in intensity but as time progresses the overall splashing and intensity increases. As the eruption gets close, the splashing and boiling becomes almost continuous and will often have short surges to one to two feet high. A half hour or more before the eruption, two small side vents to the right of the main vent also start splashing. Then, as the geyser gets even closer to erupting, a crack in the sinter between the two side vents and the boardwalk starts to bubble and surge a little. At this point, with the main vent boiling almost constantly and surging periodically to a foot or two, with the two side vents splashing and with the small crack gurgling, one of two things can happen. If the geyser is being regular, there will probably be an eruption within the next 30 minutes. If the geyser is being irregular, this type of activity may continue for 4 or more hours. To judge what is going to happen, it is best to know what the recent intervals have been and if it has been regular. If you don't know this or even if you do, you should look at the meadow behind the geyser. If it is wet, with standing water, then the interval will likely be short and the geyser probably will erupt relatively soon. If it is dry, then be prepared for a long wait.

Electronic Monitor Files
Aurum eruptions for 1997.txtAurum eruptions for 1998.txt
Aurum eruptions for 1999.txtAurum eruptions for 2000.txt
Aurum eruptions for 2001.txtAurum eruptions for 2002.txt
Aurum eruptions for 2003.txtAurum eruptions for 2004.txt
Aurum eruptions for 2005.txtAurum eruptions for 2006.txt
Aurum eruptions for 2007.txtAurum eruptions for 2008.txt
Aurum eruptions for 2009.txtAurum eruptions for 2010.txt
Aurum eruptions for 2011.txt 

Some of the temperature data used to derive the eruption times and durations used in this section were collected by Ralph Taylor under a National Park Service research permit, and the remainder was collected by personnel working for the Geology Department of the Yellowstone Center for Resources (including Ralph Taylor). The loggers are a combination of loggers owned by the NPS and Ralph Taylor. Analysis of the raw temperature data to extract the eruption data was performed by Ralph Taylor. The eruption time files on this website may be used provided that Yellowstone National Park is credited for the temperature data and Ralph Taylor is credited for the eruption times.

Activity Recorded by Data Logger - by Ralph Taylor  

Aurum Geyser has been monitored electronically since 1997. Data from 1997 to mid-2003 covers only the summer months, generally from late June to early October, but since the mid-2003 the record is nearly complete. It took some experimentation to locate the thermistor for Aurum to catch all of the eruptions (the wind can blow the water column in various directions) but eventually a suitable location was found. Aurum's preplay splashing can create a substantial temperature rise which makes detecting the actual eruption challenging.

Because of the relatively long sample intervals (the earlier data sets use sample intervals of 30 seconds and more recent ones use a sample interval of 1 minute) it is not feasible to determine Aurum's durations. However, all eruptions that I am aware of last from about 55 seconds to about 70 seconds.

Aurum is unusual in that it responds to changes in weather or ground water table, or possibly both. The intervals tend to be short and regular (with mean and median intervals under 4 hours in 2005 and 2006) in the winter months, and long and highly variable (mean and median intervals approaching 8 hours and maximum intervals of 18 to 24 hours) in dry summer months. In the time for which year-round data is available the eruption intervals begin rising in early spring but the shift to what has been called "summer mode" is most dramatic in June. The minimum intervals remain at the 4 hour level except in July-September but the trend is clearly to long intervals. In 2007, a year with a low snowpack, Aurum changed to "summer mode" in late April. In 2008 the switch to longer intervals occurred much later, possibly because of the heavy snowpack. The change to "summer mode" in 2008 began on 13 June, and by 17 June intervals in excess of six hours were common. By 29 June an interval of nearly 12 hours has been recorded. In 2009, the change to "summer mode" occurred in two periods; from 15 May to 1 June and then from 16 June to early October. In 2010, the change to "summer mode" occurred in mid-June (the first interval over 6h was on 14 June) and the switch to "winter mode" occurred about 11 November.

Activity in 2011  
The overall eruption interval statistics for Aurum Geyser in 2011 are shown at Aurum Geyser 2011 Statistics. A pdf of this summary is available at Aurum Geyser Recent Activity Summary.

The interval graph to the right shows all of the intervals for the current year. 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 diamonds 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 orange triangle denotes the start of eruptions of Dome Geyser which also is related to changes in activity in some features on Geyser Hill.

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The next graph shows the intervals for the past few months at an expanded time scale. Again, the yellow diamonds represent eruptions of Little Squirt and the orange diamond represents the initial eruption of a series of Dome Geyser.
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The third graph shows the activity for the month previous to the last download.
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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 15 minutes. The bar appearing above the label "3:30," for example, contains intervals from 3h16m through 3h30m.
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The final graph is the monthly maximum, mean, median, and minimum intervals.
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Activity since 1997  
Aurum's activity has been monitored only in the summer months for much of the time, so the full cycle is not shown on the graphs. The first graph shows all of the intervals recorded since 1997. The most notable change is in the maximum intervals--in 1998 and 1999 the intervals remained below 6h00m almost entirely. By 2000 the summer maximum intervals began to increase, and by 2002 intervals in excess of 9h00m were common. In 2003 there were numerous intervals over 9h00m. Since the beginning of 2004 there have been very few intervals below 3h00m.
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Once the year-round monitoring began in 2003 the pattern of summer long intervals and winter short intervals becomes more clear. The pattern shows up more clearly in the moving one-day median interval graph. In the summer of 2005 and 2006 the daily median intervals were in excess of nine hours for several weeks.
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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.
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Activity in 2010
Activity in 2009
Activity in 2008
Activity in 2007
Activity in 2006
Activity in 2005

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

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