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 -- [ Charts ]

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 Geysers

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 -- [ Charts ]

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.

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 "norma1" 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 -- [ Charts ]

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